Portopulmonary hypertension (POPH), pulmonary arterial hypertension that develops in the setting of portal hypertension, has long been of significant interest to the pulmonary, cardiology, and hepatology communities. Optimal management of POPH has been challenging to define due to a lack of evidence from clinical trials regarding pulmonary arterial hypertension therapies and uncertainty regarding the role of liver transplantation (LT). Initially, the high risk of intraoperative and early post-transplant death in predominantly untreated patients with POPH tempered consideration of LT. More recently, the observation that POPH can improve, and sometimes even resolve, following LT, has led to reconsideration of the role of LT in selected patients. The first International Liver Transplantation Society (ILTS) POPH and hepatopulmonary syndrome practice guideline was a multidisciplinary consensus of expert opinions based on available evidence. Since that publication, hemodynamic definitions, management approaches, and POPH MELD exception criteria have evolved, and there have been new randomized controlled trials in POPH as well as studies regarding long-term outcomes. In order to ensure the guidelines remained current and reflected recent evidence, the original writing committee of the 2016 guidelines, leaders of the ILTS Cardiovascular Special Interest Group, and colleagues active in POPH research were invited to participate in the writing committee. In this document, approved for publication by the ILTS executive council, we provide an update to the prior guidelines with expert recommendations to guide and advance POPH management. Recommendations in these guidelines are based on expert opinion and available evidence and were agreed upon by consensus.

Background Indwelling urethral catheters are regularly used in the operative setting to monitor urinary output, decompress the bladder, or manage post-operative urinary retention. Indwelling urethral catheterization can be associated with significant complications, such as nosocomial infections and urethral trauma, hence the contemporary national and institutional efforts to reduce indwelling urethral catheter usage. Objectives The purpose of this study is to investigate national trends in perioperative catheter usage across surgical procedure categories. Methods This is a retrospective study of adults who received indwelling urethral catheters during elective surgical procedures performed in United States (U.S.) hospitals during 2010-2017. We utilized the National Inpatient Sample (NIS) procedure codes to identify surgical procedure types and insertions of indwelling urethral catheters. Yearly catheterization rates were utilized to assess significant differences in nationwide temporal trends. Results We sampled 81,128,725 perioperative catheterizations across twelve procedure categories. When specific categories were examined separately, the annual proportion of procedures utilizing catheterization decreased for eye (−0.05% [95% CI, -0.10%; -0.02%], p-value 0.013), musculoskeletal (−0.04% [95% CI, -0.09%; 0.003%] p-value 0.063), and urinary system surgeries (−0.54% [95% CI, -0.76%; -0.33%] p-value 0.001). The proportion that utilized urethral catheters increased annually for female reproductive (+0.05% [95% CI, 0.04%; 0.07%] p-value <0.001), male reproductive (+0.31% [95% CI, 0.18%; 0.44%] p-value 0.001), and respiratory system surgeries (0.08% [95% CI, 0.02%; 0.13%] p-value 0.015). When all operative procedures were examined together, the overall annual proportion involving urethral catheterization did not significantly vary during 2010-2017. Conclusion Despite wide dissemination of clinical guidelines and institutional efforts to reduce catheterizations, we observed no significant changes in the overall proportion of all surgical procedures (irrespective of procedure category) that utilized urethral catheters during our study period. ### Competing Interest Statement Dr. Gregory Thoreson actively participates in research in conjunction with the Department of Bioengineering at the Erik Jonsson School of Engineering and Computer Science, University of Texas, Dallas, TX evaluating non invasive alternatives for indwelling urethral catheter use. No financial compensation exists for this research. ### Funding Statement The statistical analysis of this study was funded in part by research priority funding from the Baylor Scott & White Dallas Foundation. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Surgical Research Peer Review Committee of the Department of Surgery at Baylor University Medical Center reviewed the proposal and recommended that it be granted IRB approval under the Department of Surgery umbrella IRB protocol. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

*Department of Anesthesiology, Baylor University Medical Center, Dallas, TX †Department of Surgery, Annette C and Harold C. Simmons Transplant Institute, Baylor University Medical Center, Dallas, TX The authors report no conflicts of interest. [email protected]

Background: Adequate pain control is essential for patients undergoing liver transplantation (LT). Multiple analgesic strategies have been implemented during the perioperative period. There is no consensus on the optimal perioperative analgesia management. Objectives: To provide recommendations, on the optimal perioperative analgesia management for LT. Data Sources: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. Methods: A systematic review and meta-analysis following PRISMA guidelines and recommendations using GRADE. Studies describing outcomes, morbidity, mortality, pain scores, intensive care unit and hospital length of stay in patients that received different pain management techniques during and after LT were included (CRD42021243282). Results: One thousand nine hundred ten articles were screened, but only two randomized controlled trials, one prospective and six retrospective studies were included. The opioid-avoidance protocols included, thoracic epidural analgesia (TEA), Transversus Abdominis Plane (TAP) block, as well as other non-opioid analgesics, resulted in improved short-term outcomes. Mortality was reduced in this group versus control cohorts (OR = 0.51; CI 0.14, 1.83; P = 0.350), Time to extubation, and intensive care unit LOS were shorter; pain scores after surgery were lower in opioid-avoidance group (percentage decrease, 35%, 12%, and 55%, respectively). However, hospital LOS was longer (percentage increase 8%). Conclusions: Opioid-avoidance analgesia management for LT results in improved short-term outcomes. (Quality of Evidence; Moderate to low | Grade of Recommendation; Weak). Medications such as acetaminophen(paracetamol), gabapentin, ketamine, tramadol and local anesthesia may be used instead of, or as adjuncts to opioids for postoperative analgesia. Overall evidence remains weak and more robust studies are required.

Ventilation or breathing is vital for life yet is not well monitored in hospital or at home. Respiratory rate is a neglected vital sign and tidal volumes together with breath sounds are checked infrequently in many patients. Medications with the potential to depress ventilation are frequently administered, and may be accentuated by obesity causing airway obstruction in the form of sleep apnea. Sepsis may adversely affect ventilation by causing an increase in respiratory rate, often a very early sign of infection. Changes in ventilation may be early signs of deterioration in the patient.

Electroencephalographic (EEG) monitoring to indicate brain state during anesthesia has become widely available. It remains unclear whether EEG-guided anesthesia influences perioperative outcomes. The sixth Perioperative Quality Initiative (POQI-6) brought together an international team of multidisciplinary experts from anesthesiology, biomedical engineering, neurology, and surgery to review the current literature and to develop consensus recommendations on the utility of EEG monitoring during anesthesia. We retrieved a total of 1023 articles addressing the use of EEG monitoring during anesthesia and conducted meta-analyses from 15 trials to determine the effect of EEG-guided anesthesia on the rate of unintentional awareness, postoperative delirium, neurocognitive disorder, and long-term mortality after surgery. After considering current evidence, the working group recommends that EEG monitoring should be considered as part of the vital organ monitors to guide anesthetic management. In addition, we encourage anesthesiologists to be knowledgeable in basic EEG interpretation, such as raw waveform, spectrogram, and processed indices, when using these devices. Current evidence suggests that EEG-guided anesthesia reduces the rate of awareness during total intravenous anesthesia and has similar efficacy in preventing awareness as compared with end-tidal anesthetic gas monitoring. There is, however, insufficient evidence to recommend the use of EEG monitoring for preventing postoperative delirium, neurocognitive disorder, or postoperative mortality.

In an attempt to understand human physiological signals when an individual is subjected to pain, we set up a tonic pain experiment in a laboratory setting. The subjects’ physiological signals were recorded, timestamped, and compared to an initial 30 second baseline measurement. Subjects were also asked to verbally state their level of pain based on a visual analog scale in order to compare reported pain levels with physiological signals. The physiological signals measured were: Electroencephalography (EEG), Pupillary Unrest Under Ambient Light (PUAL), Skin Conductance (SC), Electromyography (EMG), Respiration Rate (RR), Blood Volume Pulse (BVP), Skin Temperature (ST), Blood Pressure (BP), and Facial Expression (FE). ANOVA and frequency domain analyses were conducted on the data in order to determine whether there was a significant difference between the ‘pain’ and ‘no pain’ (baseline) states of an individual. Based on our results, skin conductance, PUAL, facial expression, and EEG signals were theorized to be good signals for the classification of tonic pain, or any pain applied directly to an individual.

BACKGROUND:This study was conducted to determine effect of lower measured hepatic arterial (HA) flow (<400 mL/min) on biliary complications and graft survival after deceased donor liver transplantation. Hepatic artery is the main blood supply to bile duct and lack of adequate HA flow is thought to be a risk factor for biliary complications. METHODS:A retrospective review of 1300 patients who underwent deceased donor liver transplantation was performed. Patients with arterial complications were excluded to eliminate potential contribution to biliary complications from HA thrombosis. Patients were divided into low (<400 mL/min; N = 201) and high (≥400 mL/min; N = 1099) HA flow groups. Incidence of biliary complications and graft survival were analyzed. RESULTS:HA flows less than 400 mL/min were associated with increased rate of biliary strictures in younger donors (<50 years old), and in patients with duct-to-duct anastomoses (P = 0.028). Lower HA flows were associated with decreased graft survival (P = 0.013). Donor older than 50 years was associated with increased rate of biliary strictures (hazard ratio [HR], 1.67; 95% confidence interval [CI], 1.14-2.45; P = 0.0085) and graft failure (HR, 1.68; 95% CI, 1.35-2.1; P <0.0001) on multivariate analyses. HA flow less than 400 mL/min was associated with biliary strictures (HR, 1.53; 95% CI, 1.04-2.24; P = 0.0297) on univariate analysis only. CONCLUSIONS:HA flow less than 400 mL/min was associated with higher rate of biliary strictures in younger donors with duct-to-duct reconstruction and lower graft survival. A consideration should be given to increase the intraoperative HA flow to prevent biliary strictures in such patients.

Adequate portal vein (PV) flow in liver transplantation is essential for a good outcome, and it may be compromised in patients with portal vein thrombosis (PVT). This study evaluated the impact of intraoperatively measured PV flow after PV thrombendvenectomy on outcomes after deceased donor liver transplantation (DDLT). The study included 77 patients over a 16‐year period who underwent PV thrombendvenectomy with complete flow data. Patients were classified into 2 groups: high PV flow (>1300 mL/minute; n = 55) and low PV flow (≤1300 mL/minute; n = 22). Postoperative complications and graft survival were analyzed according to the PV flow. The 2 groups were similar in demographic characteristics. Low PV flow was associated with higher cumulative rates of biliary strictures (P = 0.02) and lower 1‐, 2‐, and 5‐year graft survival (89%, 85%, and 68% versus 64%, 55%, and 38%, respectively; P = 0.002). There was no difference in the incidence of postoperative PVT between the groups (1.8% versus 9.1%; P = 0.19). No biliary leaks or hepatic artery thromboses were reported in either group. By multivariate analyses, age >60 years (hazard ratio [HR], 3.04, 95% confidence interval [CI], 1.36‐6.82; P = 0.007) and low portal flow (HR, 2.31; 95% CI, 1.15‐4.65; P = 0.02) were associated with worse survival. In conclusion, PV flow <1300 mL/minute after PV thrombendvenectomy for PVT during DDLT was associated with higher rates of biliary strictures and worse graft survival. Consideration should be given to identifying reasons for low flow and performing maneuvers to increase PV flow when intraoperative PV flows are <1300 mL/minute. Liver Transplantation 23 1032–1039 2017 AASLD.

The provision of anesthesia for a liver transplant program requires a dedicated team of anesthesiologists. Liver transplant anesthesiologists must have an understanding of liver physiology and anatomy; the spectrum of clinical disease associated with liver dysfunction; the impact of warm and cold ischemia times, surgical techniques in liver transplantation, and the impact of ischemia-reperfusion syndrome; and optimal practices to protect the liver. The team must provide a 24-hour service, be actively involved in the selection committee process, and stay current with advances in the subspecialty.

Potential conflict of interest: Nothing to report. TO THE EDITOR: The pre–liver transplant cardiovascular evaluation of recipients routinely includes echocardiography to evaluate for the presence of pulmonary hypertension (pHTN), as patients with moderate or severe pHTN have significantly increased perioperative morbidity and mortality. A recent article by Khaderi et al.1 suggested that portopulmonary hypertension carries even longer‐term risks in post–liver transplant patients. It has become standard for patients in whom screening echocardiography suggests systolic pulmonary artery (PA) pressures >45 mm Hg to undergo confirmatory invasive testing with right heart catheterization (RHC). This allows for both confirmation of these findings, as well as initiation of treatment (where appropriate) for pHTN, and subsequent successful transplantation.2 The direct assessment of a patient's pulmonary pressures requires invasive instrumentation. In a large series of patients with pHTN, the overall risk of complication is approximately 1.1%, mostly due to the access site and bleeding risk.4 In the general population, the presence of elevated international normalized ratio (INR) or thrombocytopenia increases the risk of invasive cardiac procedures and is a relative contraindication to heart catheterization. In end‐stage liver disease patients, there are few data looking at the magnitude of the increased risk. Although there is a general assumption that this risk may be mitigated by administration of blood products (such as fresh frozen plasma or platelets), vitamin K, or recombinant factor VIIa, there are no data to support these maneuvers.5 RHC has traditionally been performed using catheters up to 8 Fr in size, placed percutaneously through the internal jugular or common femoral vein. Smaller catheters, compatible with sheaths down to 5 Fr in size, make the potential for bleeding less, but there is always the possibility that bleeding complications (sometimes due to inadvertent arterial punctures) can occur when making a venous puncture. We describe the use of a novel pressure wire to easily and safely evaluate a patient's pulmonary pressures without the need for additional venous punctures or blood products. Materials and Methods A 56‐year‐old man with a history of alcoholic cirrhosis and portal hypertension presented to our hospital with increasing fatigue over a 3‐month period of time culminating in admission for acute hepatic encephalopathy, prerenal azotemia, ascites, and acute gastrointestinal bleeding from esophageal varices (Model for End‐Stage Liver Disease score of 33). His workup included a routine transthoracic echocardiogram, which showed a right ventricular systolic pressure of >50 mm Hg (peak). Cardiology was consulted for RHC to better quantify and to confirm pulmonary hypertension. Given his baseline thrombocytopenia (platelet count 21,000) and INR of 2.3, he was felt to be a higher than normal risk for cardiac catheterization. As an alternative to traditional RHC, a specialty coronary pressure wire (0.014 inch, 185 cm, Verrata Pressure Guide wire, Volcano Corporation, San Diego, CA) was placed percutaneously through an existing 20 gauge antecubital intravenous (IV) needle (Figs. 1 and 2).Figure 1: (A) A Verrata Pressure Guide wire (Volcano Corporation) is a 185‐cm length, 0.014‐inch coronary wire, which has a pressure sensor 3 cm from the distal tip. (B) To insert it into the body to measure right heart pressures, a micropuncture needle is used to cannulate the injection port of a standard peripheral IV. Once the wire is inserted through the IV, it is manipulated into the right heart where pressures are measured.Figure 2: (left) The wire is manipulated manually, traversing through the subclavian vein, superior vena cava, right atrium, and right ventricle until it is placed into position into the pulmonary artery (middle). (right) Pulmonary artery pressures are obtained.Results Using this technique, we were able to accurately measure this patient's PA pressures without an additional venous puncture and without the administration of preprocedural blood products. There was no need for any type of premedication or sedation, no after care, and at the end of the procedure, the patient was transferred back to his hospital room. Pulmonary pressures were found to be as follows: 26 mm Hg systolic, 9 mm Hg diastolic, with a mean PA pressure of ∼15 mm Hg (Fig. 2). The patient subsequently underwent successful orthotopic liver transplantation after being listed for transplant. PA pressures, measured at the beginning of the surgery, confirmed normal right‐sided cardiac pressures. Discussion The pressure wire is typically used in evaluation of borderline coronary stenoses, allowing for more accurate determination of those lesions which may appear noncritical, but which are functionally impeding the flow of blood to the myocardium. The sensor on the wire is typically normalized to the pressure in the aorta, and then when placed across a coronary stenosis, it is able to measure a pressure drop across a lesion. Any lesion which is <0.8 is considered functionally stenotic, and studies have shown that there is a significant patient benefit if angioplasty is directed toward those lesions in particular. Use of the pressure wire to measure absolute pressures is not as well described, but the capability exists to use the wire for simple noncomparative measurements using the gradient function on the console. Use of this wire to measure pressures in circumstances other than in the determination of severity of coronary stenosis has been described, although the use in the pulmonary vasculature has been limited to pediatric patients to measure congenital pulmonary stenosis–related pulmonary hypertension.6 Use of this technique routinely is likely unnecessary given the safety of traditional methods, as well as the higher cost of the pressure wire compared to traditional Swan‐Ganz catheters. However, there may be circumstances where the need for accurate and safe measurements of PA and right heart pressures are worth the incremental cost. Unlike Swan‐Ganz measurements, one cannot perform a thermodilution measurement of cardiac output, nor can one obtain a wedge pressure. In the circumstances described, neither of these measurements was pertinent to the question at hand or would have influenced decision making regarding candidacy for liver transplantation. If this particular patient's pressures were found to be elevated and additional information regarding left ventricular end diastolic pressures (LVEDP) felt pertinent to the patient's treatment, a balloon‐tipped catheter may have been necessary to determine left ventricular filling pressures. In conclusion, we present the first reported description of the use of a coronary pressure wire to obtain right heart pressures in a patient in whom traditional invasive measurement was prohibitively risky. In patients who are at high risk for bleeding due to thrombocytopenia, liver dysfunction, or in whom additional access is unlikely to be successful, this technique affords a novel means to accurately assess intracardiac pressures.

In Brief Two distinct pulmonary vascular disorders, hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) may occur as a consequence of hepatic parenchymal or vascular abnormalities. HPS and POPH have major clinical implications for liver transplantation. A European Respiratory Society Task Force on Pulmonary-Hepatic Disorders convened in 2002 to standardize the diagnosis and guide management of these disorders. These International Liver Transplant Society diagnostic and management guidelines are based on that task force consensus and should continue to evolve as clinical experience dictates. Based on a review of over 1000 published HPS and POPH articles identified via a MEDLINE search (1985-2015), clinical guidelines were based on, selected single care reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Guidelines are presented in 5 parts; I. Definitions/Diagnostic criteria; II. Hepatopulmonary syndrome; III. Portopulmonary hypertension; IV. Implications for liver transplantation; and V. Suggestions for future clinical research. Practice guideline for the management of Hepatopulmonary Syndrome and Portopulmonary Hypertension are set forth in this publication. The work is comprehensive and reflects current best practice and an international consensus.

Two distinct pulmonary vascular disorders, hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) may occur as a consequence of hepatic parenchymal or vascular abnormalities. HPS and POPH have major clinical implications for liver transplantation. A European Respiratory Society Task Force on Pulmonary-Hepatic Disorders convened in 2002 to standardize the diagnosis and guide management of these disorders. These International Liver Transplant Society diagnostic and management guidelines are based on that task force consensus and should continue to evolve as clinical experience dictates. Based on a review of over 1000 published HPS and POPH articles identified via a MEDLINE search (1985-2015), clinical guidelines were based on, selected single care reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Guidelines are presented in 5 parts; I. Definitions/Diagnostic criteria; II. Hepatopulmonary syndrome; III. Portopulmonary hypertension; IV. Implications for liver transplantation; and V. Suggestions for future clinical research.