Quality indicators and outcomes in ambulatory surgery

Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.Purpose of reviewQuality indicators are used to monitor the quality and safety of care in ambulatory surgery, a specialty in which major morbidity and mortality remain low. As the demand for safe and cost-effective ambulatory surgical care continues to increase, quality indicators and metrics are becoming critical tools used to provide optimal care for these patients.Quality indicators are tools used by both regulatory agencies and surgical centers to improve safety and quality of ambulatory surgical and anesthetic care. These metrics are also being used to develop value-based payment models that focus on efficient, safe, and effective patient care. Patient reported outcome measures are a growing method of collecting data on the satisfaction and postoperative recovery period for ambulatory surgical patients. Monitoring of perioperative efficiency and utilization using quality metrics are important to the financial health of ambulatory surgical centers.Quality indicators will continue to play a growing role in the monitoring of quality and safety in ambulatory surgery, especially with the trend towards value-based reimbursement models and efficient, cost-effective surgical care. Additionally, quality indicators are useful tools to monitor postoperative patient outcomes and recovery pathways and the efficiency of operating room utilization and scheduling.Papers of particular interest, published within the annual period of review, have been highlighted as:Ambulatory surgery continues to expand in volume and scope as a preferred alternative to inpatient surgery owing to many advantages such as increased patient satisfaction and cost-effectiveness through reduced hospital stays. As the demand for ambulatory surgery continues to increase, it will become essential to continue monitoring the quality and safety of outpatient surgical and anesthesia services.Quality indicators are tools that can be useful to clinicians, healthcare administrators, and patients to make informed decisions regarding surgical and anesthetic care. These metrics are critical to the monitoring of patient safety and quality of care. In the ambulatory surgery arena specifically, quality indicators can be used to guide the optimal selection of the types of procedures and patients that are most suitable to receive ambulatory surgery. They can also help guide operating room efficiency and utilization. Through the growing use of patient reported outcome measures, patient satisfaction and recovery can be more routinely monitored for ambulatory surgical patients. (Fig. 1)Overview of outcome measures in ambulatory surgery.This manuscript will review the landscape of the most relevant quality indicators and outcomes in ambulatory surgery to date, focusing on their implementation and impact on patient safety and quality of care. no caption availableIncreasingly complex surgical procedures are now more routinely performed on an outpatient basis. Additionally, ambulatory anesthesiologists are routinely caring for medically complex patients with multiple comorbidities. Despite these trends, the overall morbidity and mortality rates remain low in ambulatory surgery [1-4], making these traditional outcome measures less relevant to the monitoring of quality and safety in ambulatory surgery. A recent retrospective analysis compared the safety of elective outpatient versus inpatient surgeries for specific current procedural terminology (CPT) codes representing the top 50 surgeries done on an outpatient basis 25-75% of the time using the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database [5]. Through their analysis of the NSQIP database from 2005 to 2018, the authors noted an increase in the rates of outpatient versus inpatient surgery over the course of the study period. Patients who underwent outpatient surgery had fewer comorbidities compared to those who underwent inpatient surgery, and there was a reduced likelihood of 30 day morbidity and mortality for outpatient compared to inpatient surgeries with both unadjusted and risk-adjusted analyses [5].Safe surgical care can be broadly defined as the delivery of surgical and anesthetic services in the absence of preventable adverse events. There are many stakeholders in the delivery of safe care for the ambulatory surgical patient. Patients and their clinicians are highly invested in safe outcomes. Additionally, the overall financial health and reputation of the surgical center is dependent upon patient safety.Ambulatory surgery, like all other areas of healthcare, is highly regulated by professional organizations and regulatory bodies at both the federal and state levels. This regulation is crucial to maintain national standards for patient safety and quality of care. With regards to regulatory monitoring, an ambulatory surgery center must maintain appropriate licensing and credentialing, maintain specific facility standards, ensure staff are qualified and trained appropriately, adhere to infection control and medication safety guidelines, ensure proper record keeping, and report adverse events.The Centers for Medicare and Medicaid Services (CMS) has published requirements which must be met for an ambulatory surgery center to receive Medicare payments (called "Conditions for Coverage") [6]. CMS also maintains a quality reporting system for ambulatory surgery centers called the Ambulatory Surgical Center Quality Reporting (ASCQR) program, which was established in 2012 after encouragement from the Ambulatory Surgery Center Association. Annual submission to the ASCQR is required by ambulatory surgery centers to avoid potential Medicare payment reductions. The 2023 calendar year rules incorporate required reporting of major complications including hospital admissions or transfers after outpatient procedures, patient burns and falls, wrong site/side/patient/procedure/implant events, and unplanned anterior vitrectomy after cataract removal. The rules also require reporting the percentage of patients who are normothermic on arrival to postoperative anesthesia care unit (PACU) and the percentage of healthcare personnel who are vaccinated for coronavirus disease 2019 [7].Another major regulatory body, the Joint Commission, recently released "2023 Ambulatory Healthcare National Patient Safety Goals." This document focuses on proper surgical site identification, surgical time outs, medication safety, and prevention of surgical site infections [8].As ambulatory surgery continues to grow in demand, patient quality and safety will continue to be a focus for regulatory bodies that set standards and guidelines. Quality indicator measures are a key tool used by these groups to standardize the monitoring of quality and safety nationally. Patient-reported outcome measures (PROMS) have become a significant tool in many different areas of healthcare, including ambulatory surgery. PROMs are self-reported information about a patient's health status, symptoms, functional status, and quality of life. By definition, these measures are patient-centered and can help patients feel more in control of their healthcare. In ambulatory surgery, PROMs can help to assess patient satisfaction with the care received and the quality of postoperative recovery. PROMs are especially relevant in the ambulatory setting where the patient is discharged the same day. Other significant uses of PROMs in the ambulatory surgery setting include research and quality improvement. Additionally, through the increased use of electronic PROM surveys, a robust amount of data can be generated and used for investigational and quality improvement purposes.One of the most commonly used PROMs in surgical patients are quality of recovery surveys, which are surveys designed to evaluate and quantify various aspects of patient recovery from surgery and anesthesia. The Quality of Recovery 40 (QoR-40) is a well-established, validated survey used to measure the quality of postoperative recovery among surgical patients [9]. This self-administered questionnaire consists of 40 items that cover multiple domains, including physiologic recovery, physical independence, psychological recovery, social recovery, and pain. It has been widely validated across multiple surgical subspecialties, including ambulatory surgeries. A systematic review looking at postoperative recovery outcomes within one week of ambulatory surgery found the QoR-40 to be the most appropriate method to measure patient-related outcomes that can be used in clinical trials [10]. An abbreviated version called the Quality of Recovery 15 (QoR-15) has also been similarly validated for the monitoring of postoperative patient recovery [11]. Further examples of postoperative recovery surveys include the Postoperative Quality of Recovery Scale [12], the Surgical Recovery Index [13], and the Patient Satisfaction Questionnaire short form [14]. Additionally, the Standardized Endpoints in Perioperative Medicine-Core Outcome Measures in Perioperative and Anaesthetic Care group made recommendations for patient-centered outcome measures for use in perioperative studies, some of which are relevant to ambulatory surgery such as the Bauer patient-satisfaction measure as well as the previously mentioned QoR surveys [15,16].Traditionally, PROM surveys have been administered during postoperative follow up via clinic visits or phone calls. A recently published randomized clinical trial compared postoperative follow-up recovery surveys administered via smartphone app versus traditional in person follow-up. Patients who underwent oncologic breast reconstructive surgery or major gynecologic oncology surgery were randomized to complete the QoR-15 and patient satisfaction questionnaire (PSQ-III) postoperatively at multiple time points via smartphone application or in person follow-up in a surgical clinic. They found significantly higher QoR-15 scores and similar PSQ-III scores between the study and control groups, supporting the use of app-based postoperative recovery follow-up surveys [17]. Smartphone application-based PROM surveys can provide important follow up data that may otherwise be missed until the initial postoperative clinic visit, which often comes several weeks following surgery. A recent prospective observational study looked at the use of QoR-40 administration specifically in ambulatory surgical patients, comparing survey results obtained via traditional phone-call based follow-up versus electronic digital administration. In this single-center study, the group found no significant differences between survey scores obtained via a phone call versus digitally via an emailed survey [18]. Their finding furthers the idea that electronic based PROMs may be valid alternatives to phone call-based PROM follow-up, which may be more convenient for patients and less time consuming and costly to clinicians and researchers.The growing popularity of ambulatory surgery owes in part to it being more cost-effective than traditional inpatient surgery. Ambulatory surgical patients have reduced lengths of stays and use fewer healthcare resources than inpatients. Overburdened hospital systems can offset the demand for hospital beds and other healthcare resources by shifting outpatient surgeries to a dedicated ambulatory surgical center. The efficient use of ambulatory operating rooms and staff can maximize the overall number of outpatient surgeries performed in a given time period and thus, maximize cost-effectiveness. Achieving efficiency in the ambulatory surgery center is a continuous process of matching operating room utilization with capacity, accurate surgical scheduling, appropriate staff assignments, and maintenance of required materials.Surgical scheduling is a dynamic process that should take into account perioperative staffing numbers, surgeon specific time predictions for booked surgical procedures, and operating room turnover times. Optimal scheduling of surgeries in the ambulatory surgical center leads to a minimization of operating room underutilization and overutilization. Underutilization leads to lost revenue. Overutilization also leads to lost revenue in the form of overtime staff pay and delays and/or cancellations for surgeries scheduled for later in the day due to overbooking. A recent cross-sectional retrospective study looked at the association between the timing of elective surgery scheduling and operating room overutilization. Elective surgeries with planned postoperative admissions that were "squeezed-in" to the schedule within 7 days prior to surgery were associated with a significantly higher likelihood of OR overutilization. Interestingly, no difference was found for elective outpatient surgeries scheduled within 7 days prior to surgery [19].Process metrics such as "first case on time start" percentage and "turnover time," are often used to achieve optimum OR utilization and scheduling accuracy. In contrast, recent research has called these metrics into question and suggests that surgeon estimated case duration accuracy is a better predictor of whether operating room days end on time [20]. More studies looking at the timing of surgery scheduling and operating room efficiency are needed to elucidate these trends further, but this study highlights the current work being done to develop more accurate predictor models for optimal operating room utilization.Another crucial component to efficiency and cost-effectiveness of ambulatory surgery is postoperative length of stay in the PACU. PACU stay lengths vary due to patient comorbidities, anesthetic management, and surgical procedure type. PACU stays are lengthened by common complications such as postoperative nausea and vomiting, pain, hypothermia, respiratory issues, and hemodynamic instability. Among traditional inpatient surgeries, there has been a trend to streamline surgical, anesthetic, and postoperative care using enhanced recovery after surgery (ERAS) protocols with the goal of earlier patient discharge from the hospital and improved outcomes. ERAS programs have begun emerging in the care of ambulatory surgical patients as well, due to the potential benefits of speedier functional recovery and minimized PONV and pain. Afonso et al. describe the recent implementation of an ERAS protocol for selected ambulatory surgical procedures at an academic, free-standing surgical center [21]. Through retrospective analysis of the recovery of included patients, they noted a decrease in total intraoperative opioid administration over the study period. Throughout the duration of the study period, they also noted increased rates of total intravenous anesthesia (TIVA) administration and decreased time to convert to oral opioids postoperatively [21]. Although this was a feasibility study that lacks a control group, it does highlight the successful implementation of an ERAS protocol in an ambulatory surgery center. ERAS protocols in ambulatory surgery, which emphasize patient satisfaction with recovery and optimize healthcare resource utilization, will likely continue to grow in popularity.Healthcare value is defined as safe, effective, efficient care which minimizes costs (e.g. quality/cost). Ambulatory anesthesiologists are in a unique position to influence healthcare value as health insurance payment trends drive procedures into the ambulatory arena. The healthcare insurance industry is undergoing a historic shift toward value-based care and away from the traditional fee-for-service payment model in which reimbursement is based on the services and procedures performed. Value-based care and the associated payment models incentivize desired provider behaviors to increase efficiency and effectiveness and reduce costs [22].Anesthesiology largely remains reimbursed by the fee-for-service model, but this is likely to change. The CMS Quality Payment Program is designed to shift healthcare away from the fee-for-service model with most anesthesiology groups participating in the Merit Based Incentive Payment program (MIPS) [23]. In the future, traditional MIPS will be replaced by MIPS Value Pathways which are intended to streamline reporting requirements by decreasing the number of reporting measures and focusing on measures which are most relevant to each specialty [24].While there are few if any value metrics currently in use, it is likely that the practice of anesthesiology, especially in the ambulatory setting, will be impacted by value-based insurance reimbursement. Ambulatory anesthesiologists will have to continue to look for opportunities to impact healthcare value in the perioperative setting and develop measures to quantify it [25].As patients recover from increasingly complex surgical procedures at home, it becomes ever more important to track quality indicators and outcomes in ambulatory surgery. To date, mortality and serious morbidity are rare after ambulatory surgery. Beyond traditional outcomes such as morbidity, PROMs can assist clinicians and researchers in understanding and optimizing the postoperative recovery experience for patients. Additionally, opportunities for increased efficiency should be constantly sought and evaluated in order to optimize access to ambulatory surgery and contain costs. Finally, ambulatory surgery stakeholders should maintain awareness of regulatory standards for the purposes of accreditation, reimbursement, and maintaining and improving quality of care.None.