Background In some regions, females are less likely to receive public-initiated resuscitation, potentially due to the need to expose the chest and breasts for proper automated external defibrillator (AED) pad placement. We conducted a scoping review to investigate the breadth of the existing literature and knowledge gaps on bra (brassière) removal and AED pad application. Methods Studies that examined bra removal and outcomes associated with AED pad placement and defibrillation in cardiac arrest were eligible. We searched three databases (Medline, Embase, and Cochrane) from inception to September 26, 2024. Google and Google Scholar (first 20 pages) were searched for grey literature on October 1, 2024. The study followed the scoping review framework by the Joanna Briggs Institute. Results The search identified 287 references. Three studies met the eligibility criteria, including one animal and two manikin studies, of which two were conference abstracts. No studies examined patient outcomes. No adverse events were reported with defibrillation in a pig model with AED pads in direct contact with a bra’s underwire. No difference in time to pad placement or shock delivery was seen with bra removal in simulation. One simulation study reported female manikins were less likely to be completely de-robed, including bra removal, which was attributed to social norms, modesty, and lack of awareness. Conclusion Scant evidence is available on the need for bra removal and outcomes associated with AED application. Further research is needed to explore whether bra removal is imperative for AED pad placement and defibrillation.

Background:Out-of-hospital cardiac arrest (OHCA) is a major public health problem. This study aims to describe the international variations in the practices related to the initiation, termination, and refraining from resuscitation of adult patients (≥18 years) with a non-traumatic OHCA. Methods:An exploratory descriptive study was conducted using a cross-sectional online survey. The respondents were recruited using snowball sampling technique. Framework analysis was used to identify key themes in responses, with descriptive statistics summarising data trends. Results:The study collected responses from 59 countries. Our findings reveal that respondents from 59.3% of countries reported that they initiate resuscitation in all cases where the patients do not show obvious signs of irreversible death or do not have confirmed advance directives. Respondents from 15.3% of countries reported that once started, prehospital resuscitation attempts are not terminated. Prehospitally respondents from 20.3% of the countries reported that they rely exclusively on specific criteria to decide when to terminate resuscitation efforts while in 45.8%, these decisions are made at the discretion of the provider. Respondents from most countries (91.5%) reported that they refrain from resuscitation in the presence of obvious signs of irreversible death. Respondents from 57.6% of countries, reported that they refrained from resuscitation if the patient had a confirmed do-not-attempt-cardiopulmonaryresuscitation (DNACPR), while 15.3% mentioned staff safety as a reason to abstain from attempting resuscitation. Conclusion:This study reveals global variation in EMS resuscitation practices, reflecting disparities in resources, healthcare infrastructure, EMS system design, community acceptability given cultural and societal norms, and legislation.

The increased accessibility of extracorporeal membrane oxygenation following the COVID‐19 pandemic and the publication of the first randomized trial of extracorporeal cardiopulmonary resuscitation (ECPR) prompted the National Heart, Lung, and Blood Institute to sponsor a workshop on ECPR. Two more randomized trials have since been published in 2022 and 2023. Based on the combined findings and review of the evidence, an international panel of authors identified gaps in science, inequities in care and diversity in outcomes, and suggested research opportunities and next steps. The science pertaining to ECPR would benefit from the United States contributing uniform data to existing registries and sharing common data with the ELSO (Extracorporeal Life Support Organization) international registry to increase the sample size for observational research. In addition, well‐designed efficacy trials, recruiting across different regions of care evaluating long‐term follow‐up, including patient reported outcomes, cost effectiveness, and equity measures, would contribute significantly to the body of science. Workshop participants defined the population of patients with out‐of‐hospital cardiac arrest most likely to benefit from ECPR. ECPR‐eligible patients include those aged 18 to 75 years functioning independently without comorbidity; before suffering a witnessed out‐of‐hospital cardiac arrest and without any obvious cause of the cardiac arrest; presenting in a shockable rhythm and transported with mechanical cardiopulmonary resuscitation to an ECPR‐capable institute within 30 minutes, which is recommended after 3 rounds of advanced life support treatment without return of spontaneous circulation. There are significant inequities in out‐of‐hospital cardiac arrest care that need to be addressed such that outcomes are optimized for each target region before implementing ECPR in a clinical or implementation trial.

Importance:Previous studies support bystander provision of chest compression-only cardiopulmonary resuscitation (CC-CPR) for out-of-hospital cardiac arrest (OHCA). However, it is unknown whether OHCA secondary to opioid toxicity may benefit from chest compression plus ventilation CPR (CCV-CPR). Objective:To examine the association between bystander CPR technique and outcomes among both opioid-associated OHCA (OA-OHCA) and otherwise undifferentiated OHCA. Design, Setting, and Participants:This cohort study (performed from August 1, 2023, to December 31, 2024) analyzed cases of adult emergency medical services-treated OHCA that occurred from December 1, 2014, to March 31, 2020, as identified through the British Columbia Cardiac Arrest Registry. Exposures:Cases were classified as OA-OHCA based on positive postmortem toxicologic investigations, death certificates, or opioid-specific hospital-based diagnoses. All other cases were classified as undifferentiated OHCA. Main Outcomes and Measures:Favorable neurologic outcome at hospital discharge (cerebral performance category ≤2). A multivariable Utstein-adjusted logistic regression model of complete cases was used to assess the association between bystander CPR technique (CC-CPR [reference] vs both CCV-CPR and no CPR individually) with outcomes. An interaction term between the OA-OHCA and bystander CPR technique was used to estimate associations among OA-OHCA and undifferentiated OHCA cases separately. Results:The study included 10 923 OHCAs. After removing 24 cases only treated with ventilatory support, there were 1343 OA-OHCAs (median [IQR] patient age, 40 [31-50] years; 1015 [76%] male) and 9556 undifferentiated OHCAs (median [IQR] patient age, 70 [58-81] years; 6636 (69%) male). In the OA-OHCA group, bystander CCV-CPR was associated with an increased odds of a favorable neurologic outcome (adjusted odds ratio [AOR], 2.85; 95% CI, 1.21-6.75) when compared with CC-CPR. No association was detected with favorable neurologic outcome (AOR, 1.52; 95% CI, 0.82-2.82) when no CPR was compared with CC-CPR. Among undifferentiated OHCAs, no association was detected with a favorable neurologic outcome (AOR, 1.16; 95% CI, 0.80-1.67) when CCV-CPR was compared with CC-CPR. No CPR was associated with a decreased odds of a favorable neurologic outcome (AOR, 0.69; 95% CI, 0.55-0.87) when compared with CC-CPR. The interaction term was statistically significant (P for interaction = .04). Conclusions and Relevance:In this cohort study of OHCA, bystander CCV-CPR (compared with CC-CPR) was associated with improved outcomes in opioid-associated OHCA; however, this association was not observed among undifferentiated cardiac arrests. These results suggest that the optimal bystander CPR technique for OA-OHCA and undifferentiated OHCA may differ and that ventilations may improve outcomes in OA-OHCA resuscitation.

Background Out-of-hospital cardiac arrest (OHCA) is a significant cause of mortality and morbidity in North America, for which timely defibrillation of shockable rhythms is essential. Drones have been proposed as an intervention to improve response time and are being implemented in practice. Aim To determine the cost-effectiveness of drone-delivered automated external defibrillators (AEDs) for OHCAs. Methods Using data from 22,017 OHCAs in Ontario, Canada over 10 years, we developed a comprehensive computational framework combining machine learning, optimization and a Markov microsimulation model to provide an economic evaluation of 964 different drone networks across a wide range of sizes and configurations. We simulated response times, survival outcomes, lifetime quality-adjusted life-years (QALYs), lifetime healthcare costs, and 10-year operational costs for each network. Results All 964 drone networks were cost-effective. We identified 20 networks on the cost-QALY efficient frontier, each with shorter response times, more survivors across all categories, and higher costs per survivor. Historical ambulance response (i.e., standard care) had mean response time of 6 min 21 s. On the efficient frontier, average drone response times were 32% to 71% shorter than standard care. There were 1,855 (8.4%) survivors to hospital discharge in standard care, which increased by 21% to 46% across the 20 drone networks. The smallest non-dominated drone network, with 20 drones, cost $20,912 per QALY gained. All drone networks had higher net monetary benefit than standard care. Cost-effectiveness was even greater for shockable and witnessed populations. Extensive sensitivity analyses showed that our results were robust to changes in modelling assumptions. Conclusions Drone-delivered AEDs were associated with reductions in response time, mortality and morbidity, and were found to be highly cost-effective relative to standard ambulance response with no drones.

Background: Airway management is vital in paediatric resuscitation, especially since respiratory conditions are frequently the primary cause of paediatric cardiac arrest. Placement of an advanced airway device may facilitate more effective resuscitation than bag-mask ventilation but requires more skilled personnel and the time taken to perform the procedure may interfere with other vital components of resuscitation. Objectives: To assess the use of advanced airway interventions, tracheal intubation (TI) or supraglottic airway (SGA) placement, compared with bag mask ventilation (BMV) alone for resuscitation of children in cardiac arrest. Data sources: This was an update to a previous systematic review performed by ILCOR. A search of PubMed, EMBASE, and Cochrane Controlled Register of Trials (CENTRAL) was conducted for suitable studies published before 1 January 2025. This systematic review was registered as PROSPERO CRD42023482459. Study eligibility: Randomised controlled trials and non-randomised comparison studies involving airway interventions (BMV, TI, SGA) in infants and children (excluding newborn infants) in cardiac arrest in any setting were included. Study appraisal & synthesis: Investigators reviewed studies for relevance, extracted data, and assessed risk of bias using the RoB 2 and CLARITY frameworks. Critically important outcomes included survival to hospital discharge and survival with good neurological outcome. Results: We identified 20 suitable studies (13 from the original systematic review and 7 from the updated search), including 1 pseudorandomised clinical trial, 6 observational cohort studies using propensity matching, and 9 simple cohort studies suitable for meta-analysis. The majority of studies involved out-of-hospital cardiac arrest, with few studies exploring in-hospital cardiac arrest. The overall certainty of evidence was low to very low. For the critically important outcomes of survival to hospital discharge with good neurologic outcome and survival to hospital discharge, results showed no benefit from advanced airway interventions (TI or SGA) over BMV. Conclusions: There is currently no supporting evidence that an advanced airway (supraglottic airway or tracheal intubation) during CPR improves survival or survival with a good neurological outcome after paediatric cardiac arrest in any setting when compared with bag-mask ventilation.Well-designed randomised trials are needed to address this important question.

Out-of-hospital cardiac arrest (OHCA) is a leading cause of mortality. Despite public awareness campaigns, widespread cardiopulmonary resuscitation (CPR) training initiatives, and deployment of public access defibrillators, potentially life-saving bystander intervention occurs inconsistently. Mobile technologies that alert nearby lay responders or off-duty professionals to OHCA events have emerged as a strategy to increase bystander CPR and AED use. The PulsePoint Randomized Controlled Trial (RCT) is a multi-centre pragmatic RCT designed to evaluate whether alerts sent via the PulsePoint Respond mobile application increase the likelihood of bystander resuscitation attempts before paramedic arrival. The trial is being conducted within a province-wide Canadian paramedic service and a municipal fire rescue service in the USA. Eligible 9-1-1 calls for suspected non-traumatic OHCA occurring in a public (non-residential) location are randomized in real time to activation or suppression of the PulsePoint system. The primary outcome is bystander CPR or AED use prior to paramedic or firefighter arrival. Patients are included in the primary analysis if they are determined to have paramedic-treated OHCA in a public location with at least one PulsePoint user within 400 m. The target sample size is 340 patients powered at 80 % to detect a 15 % absolute increase in the primary outcome. This pragmatic trial addresses a critical evidence gap in resuscitation science. We anticipate findings will inform refinement of technology implementation, policy, guideline development, and system-level decisions regarding the implementation of mobile alert systems to improve early intervention and survival from OHCA.

Background: New devices are now available to provide real-time feedback on ventilation for basic life support providers responding to out-of-hospital cardiac arrest (OHCA). This scoping review, conducted as part of the evidence review for the International Liaison Committee on Resuscitation, aimed to examine the extent of evidence examining ventilation feedback devices and to identify research gaps regarding these devices. Methods: This scoping review was conducted using Arksey and O’Malley’s framework and reported according to PRISMA-ScR guidelines. Medline, EMBASE and Cochrane were searched from database inception to March 13th, 2025. Studies examining real-time ventilation quality feedback in humans and manikins of any design were included. Ventilation feedback devices were defined as any device that can provide information on the delivery of each insufflation (including insufflation and/or exsufflation measured volume as well as rate) and to guide the ventilation through real-time feedback. Results: We screened 794 titles, with 17 studies (including 4 conference abstracts) included: one randomised trial (RCT), one before-after prospective studies, two observational studies, one case series and 12 simulation studies. Only three simulation studies assessed a pediatric scenario. The RCT reported improved early outcomes (unadjusted return of spontaneous circulation and 30-hour survival) with real-time feedback, but no difference at hospital discharge. Two observational studies also found no change in patient outcomes, but noted improved ventilation rate and insufflation volumes. Most simulation studies showed improvements in ventilation parameters. Conclusion: Real-time feedback devices seem to improve ventilations, but we found insufficient evidence of their effect on clinical outcomes to merit a systematic review at this time. Rigorous evaluation of the clinical efficacy and effectiveness of these devices is needed.

BACKGROUND:Extracorporeal cardiopulmonary resuscitation (ECPR) is increasingly used for adults with cardiac arrest (CA) refractory to Advanced Cardiovascular Life Support (ACLS). Concerns exist that adding ECPR could worsen health inequities, defined as differences in health outcomes that are unfair or unjust. Current guidelines do not explicitly address this issue. This study narratively reviews the latest evidence on ECPR, focusing on its implications for health equity and derives a health equity tool that may serve as a basis of comparison for resuscitation sciences. METHODS:We searched the American Heart Association (AHA) and International Liaison Committee on Resuscitation (ILCOR) websites for the latest ACLS guidelines and scientific summaries on ECPR for CA and identified randomized controlled trials (RCTs) and observational studies. We identified population and individual characteristics associated with inequities based on the literature and expert opinion. These characteristics were used as a health equity tool to assess: differences in baseline risk, population exclusion and trial representation in studies, outcome analyses, and implementation barriers. We used the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) Evidence to Decision (EtD) framework to evaluate ECPR's impact on health equity. RESULTS:Four RCTs involving 435 patients were conducted in the (2/4) USA, (1/4) Czech Republic, and (1/4) Netherlands. We identified thirteen characteristics associated with health inequities. All trials took place in urban, high-resourced hospitals and excluded older adults (60-75+ years). Across all RCTs, women were under-represented, and in the two USA-based trials, Black individuals were under-represented. There was no difference in baseline rate of survival with minimal or no neurologic impairment between sexes, but an observed trend favoring younger patients (<65). One trial's subgroup analysis showed no significant differences in ECPR effectiveness by sex or age. We noted that implementing ECPR for out-of-hospital CA faces challenges due to demographic variability, differences in emergency services, access to existing ECPR programs, and limited implementation outside urban areas. CONCLUSIONS:A health equity tool based on axes of health inequities for resuscitation identified that health equity is reduced with the use of ECPR for CA. Mitigation strategies should involve evaluating demographics, health equity measures, outcomes and ensuring equitable access to ECPR across catchment areas before and after implementation.

BACKGROUND:Disparity is believed to exist between generic Utstein etiological classifications of 2004 and 2015 when compared with confirmed etiologies, but the impact of this disparity on reported survival outcomes is unknown. OBJECTIVE:This scoping review was proposed with two objectives: 1-to report outcomes based on confirmed etiology of OHCA in comparison with Utstein classified etiologies and 2- to identify outcomes of OHCA by etiology following cause-targeted interventions. METHOD:Medline, Embase, and EBM- Cochrane databases were searched from inception to 2024. Studies were selected if included population was adults with OHCA for whom survival outcomes of OHCA were reported based on the confirmed etiology compared to Utstein etiological classification (2004 or 2015) or reported based on the etiology following cause-targeted interventions. A descriptive review of included studies was conducted. RESULT:The search yielded 24,833 citations. Thirty-nine studies met inclusion criteria. These articles were predominantly published in Europe and North America between 2010-2024. The Utstein etiological classification was used in all studies (Utstein 2004; n = 31, Utstein 2015; n = 8). Survival to discharge was higher for drug overdose induced OHCA than presumed cardiac etiologies (9-83% vs 8.3-63%). For confirmed etiology of drowning, 30-day survival was higher than the rate reported by presumed cardiac etiologies (Utstein 2004) (11.5% vs 8.8%) while survival to discharge was lower following confirmed etiologies of trauma (1.7-5.1% vs 8-12%), hanging (3.3-43% vs 12-61%), respiratory disease (5% vs 9%), and intracranial hemorrhage (ICH) (11% vs 40%) compared with Utestin etiological classifications (2004 or 2015). Thrombolysis therapy resulted in better 30-day survival compared to placebo for OHCA due to presumed pulmonary embolism (16% vs 6%; p = 0.05), and conventional resuscitation resulted in higher survival for OHCA due to drowning (10.5% vs 8.6%) or respiratory disease (6.8% vs 4.54%) versus chest compression only. CONCLUSION:The reported survival outcomes for confirmed non-cardiac etiologies is inconsistent across studies compared with Utstein etiological classifications of 2004 or 2015. Better survival outcomes following few cause-targeted interventions may be attributed to etiologically well-defined patient cohorts. More vigorous case selection based on etiology may refine the reported outcomes and comparisons with interventions across published studies.

AIM:To systematically review the literature examining optimal blood pressure targets following in-hospital or out-of-hospital cardiac arrest in infants and children. (PROSPERO ID CRD42023483865). METHODS:We searched Medline, EMBASE, and Cochrane Controlled Register of Trials (CENTRAL) for randomised controlled trials and non-randomised studies for all years up to March 19, 2025. Risk of bias and certainty of evidence was assessed using Newcastle-Ottawa and GRADE. Critically important outcomes survival to hospital discharge and survival with favourable neurological outcome. RESULTS:We identified 11 observational studies, including 2855 cardiac arrest events in infants and child. No randomised clinical trials were found. Patients exposed to a systolic blood pressure (SBP) greater than 5th percentile for age within six hours of return of circulation, compared to less than 5th percentile had a higher risk of survival to hospital discharge (RR 1.41; 95 % CI [1.2-1.6]; P = 0.01) and better survival with favourable neurological outcome at hospital discharge (RR1.25; 95 % CI [1.11-1.64]; P = 0.01). Exposure to a SBP greater than 10th centile for age was also associated with increased survival at hospital discharge and survival with favourable neurological outcome at hospital discharge (RR 1.21; 95 % CI [1.00-1.33}; P < 0.01 and RR 1.22; 95 % CI [1.10-1.35}; P < 0.01 and RR respectively). Mean Blood Pressure targets (>10th percentile) and diastolic blood pressure targets (>50th percentile) were also reported and associated with improved critical outcomes. However, variation in time points, blood pressure definitions and outcome assessment limited pooled analysis. Risk of bias was low, and the certainty of evidence was very low. CONCLUSION:Early hypotension after return of circulation post cardiac arrest is associated with worse outcomes in infants and children after cardiac arrest. Patients exposed to systolic or mean arterial blood pressure targets greater than fifth and tenth percentile for age have improved risk of survival to hospital discharge and survival with favourable neurologic outcomes at hospital discharge.

Background: Nerinetide is a neuroprotectant effective in preclinical models of acute ischaemic stroke when administered within 3 h of onset. However, the clinical evaluation of neuroprotectants in this short timeframe is challenging. We sought to establish the feasibility, safety, and effectiveness of nerinetide when given before hospital arrival within 3 h of symptom onset of suspected stroke. Methods: In this multicentre, randomised, double-blind, placebo-controlled study, paramedics enrolled participants aged 40-95 years within 3 h of suspected severe stroke onset, who were previously independent, and were being taken to one of seven stroke centres in Ontario or British Columbia, Canada. The primary hypothesis was that the administration of nerinetide would result in a higher rate of good functional outcomes. Participants were randomly assigned 1:1 to intravenous nerinetide (26 mg/kg) or placebo, each in visually identical vials. Paramedics, hospital care providers, and outcome evaluators were masked to treatment assignment. The primary outcome was good functional outcome on a sliding dichotomy of the modified Rankin Scale at 90 days. Participants were assessed on day 4, 30, and 90 by the stroke center research team, in person or over the telephone. Outcomes, adjusted for age and stroke severity, were evaluated in the modified intention-to-treat (mITT) population, and in the target population of those with acute ischaemic stroke. The safety population included all participants who received the study drug. This study is registered with ClinicalTrials.gov (NCT02315443), and trial enrolment has concluded. Findings: Between March 26, 2015, and March 27, 2023, 532 participants received nerinetide (n=265) or placebo (n=267). The mITT population of suspected stroke (n=507; 254 nerinetide and 253 placebo) included 321 (63%) with acute ischaemic stroke, 93 (18%) with intracranial haemorrhage, 44 (9%) with transient ischaemic attack, and 49 (10%) with stroke-mimicking conditions. Treatment began a median of 64 min (IQR 47-100) from symptom onset. Participants randomly assigned to nerinetide had more severe strokes compared with those receiving placebo (median National Institutes of Health Stroke Scale (NIHSS) 12, IQR 5-19 vs 10, 4-18 in mITT, and 14, 7-19 vs 10, 4-18 in the acute ischaemic stroke subgroup). Overall, 145 (57%) of 254 participants in the nerinetide group and 147 (58%) of 253 in the placebo group had the primary outcome of a favourable functional outcome using the prespecified sliding dichotomy at 90 days (adjusted odds ratio 105, 95% CI 073-151; adjusted risk ratio 104, 95% CI 085-125). In the 302 patients with ischaemic stroke, the favourable functional outcome adjusted for arrival NIHSS and age favoured nerinetide (odds ratio 153, 093-252 and risk ratio 121, 097-152). In those given reperfusion therapies (thrombolysis or endovascular thrombectomy, or both) nerinetide was associated with improved favourable functional outcomes (adjusted odds ratio 184, 103-328; adjusted risk ratio 129, 101-165). There was no apparent benefit in haemorrhagic stroke or acute ischaemic stroke without reperfusion. There were no safety concerns. Interpretation: Prehospital nerinetide did not improve neurological functional outcomes in all patients with suspected ischaemic stroke in the mITT population. Nerinetide might benefit patients with acute ischaemic stroke who are selected for reperfusion therapies within 3 h of symptom onset. This finding should be confirmed in a future trial.

BACKGROUND:Current Utstein etiological classifications for out-of-hospital cardiac arrest (OHCA) are heterogenous and inaccurate when compared with robust sources. This heterogeneity may influence reporting incidence and outcomes and patient enrollment in observational studies and clinical trials. Circumstance-related factors may contribute to cardiac arrest; however, the role of these factors in improving the etiological classification of OHCA is unknown. OBJECTIVE:This scoping review was proposed to explore current evidence to identify the role of contributing factors, triggers, and prodromal symptoms of out-of-hospital cardiac arrest in the reported etiology of cardiac arrest based on emergency medical services data, medical records, or autopsy reports. METHOD:We searched Medline, Embase, and EMB review-Cochrane databases from 1946 to 2024. Studies were selected if the included population was adults with OHCA for whom the initial etiology was assigned, and any contributing factors, triggers, or prodromal symptoms of OHCA were reported. A descriptive review of the included studies was conducted. RESULT:The search yielded 24,833 citations. Seventy studies met the inclusion criteria. These studies were published predominantly in Europe and Asia between 2010 and 2024 and classified as contributing factors (n = 24), exercise (n = 13), environmental triggers (n = 24), and prodromal symptoms (n = 9). The etiology of cardiac arrest initially assigned to cardiac or obvious non-cardiac classification may be precipitated by seizures (n = 8), trauma (n = 7), alcohol or drug intoxication (n = 6), Covid-19 infection (n = 5), myocardial infarction (n = 4), suicide (n = 4), antipsychotic medications (n = 4), and illicit drug use (n = 3). Exercise and environmental factors (e.g., particulate matter (PM) 2.5µ and ambient temperature) may trigger cardiac arrest predominantly due to cardiac etiologies. Based on EMS data, approximately 50% of patients with OHCA experienced symptoms prior to cardiac arrest which suggested cardiac and non-cardiac etiologies. CONCLUSION:Many circumstance-related factors may directly or indirectly contribute to cardiac arrest etiology classification. Listing these factors in the reporting template may help prehospital personnel and data abstractors gather enough information to identify more accurately the etiology of OHCA.

Background The COVID-19 pandemic exacerbated health inequities, particularly among individuals with opioid use disorder (OUD). Disparities in vaccine uptake among people with OUD remain poorly understood. This study assessed COVID-19 immunisation rates among individuals with OUD compared with the general population in Ontario, Canada.Methods This population-based retrospective cohort study used linked administrative health data to compare COVID-19 vaccination rates between individuals diagnosed with OUD and a 10% random sample of individuals without OUD. Ontario residents aged >15 years with continuous healthcare coverage as of the censor date, 16 March 2020, were included. Inverse Probability of Treatment Weighting (IPTW) was applied to balance confounders, and Cox proportional hazards models estimated adjusted HRs (aHRs) for receiving two and three or more vaccine doses.Results The cohort included 105 733 individuals with OUD and 1 185 993 without OUD. Individuals with OUD had a lower hazard of receiving two vaccine doses (aHR: 0.75, 95% CI 0.73 to 0.76) and three or more doses (aHR: 0.69, 95% CI 0.67 to 0.70). The rate of two-dose and three-dose vaccination was also lower among those with OUD (115.3 vs 149.0 per 100 000 person-years and 44.7 vs 77.5 per 100 000 person-years).Conclusion Individuals with OUD had lower COVID-19 vaccination rates, suggesting barriers to access and uptake. Addressing these disparities through targeted interventions is crucial for equitable public health responses.

Canada's opioid crisis continues to escalate. Naloxone can effectively reverse the effects of opioid overdose. We planned a randomized trial on the effectiveness of a point-of-care overdose education and naloxone distribution (OEND) intervention on participants' performance in a simulated opioid overdose scenario. In preparation for the trial, we conducted a feasibility study which included a qualitative process evaluation aimed at eliciting participants' perspectives of the study's OEND tool and procedures, and how their lived experiences of the opioid crisis intersected with their experiences of the study. Twenty-three participants were interviewed, including people with lived experiences of opioid use or overdose, and people living in neighbourhoods or working in services where they were likely to encounter overdose. Thematic analysis of interview transcripts was informed by stigma theory. Participants' accounts depicted challenges faced by people who take opioids in their everyday lives, deep losses experienced, negative attitudes encountered, and systemic barriers to care. Participation in the study itself was portrayed as meaningful. We explored participants' experiences through three key themes: (1) who were the participants - describing their experiences related to opioid overdose, opioid use and attendant stigma; (2) why did they participate - recounting their motivations to join the study; and (3) what they thought about study processes - reflecting on the OEND materials and study procedures. Accounts revealed a sense of agency as participants confronted the opioid crisis. Our results demonstrate that people experiencing opioid use and overdose and people who care about them are eager and willing to be approached about research at point of care; participants were eager to learn overdose prevention skills and to return for follow-up study sessions. They recounted a range of motivations for participating, the most important of which is the opportunity to actively intervene, save lives and raise awareness. Trial Registration: ClinicalTrials.gov registry (NCT03821649).

INTRO: Most out-of-hospital cardiac arrest (OHCA) cases are unwitnessed, leading to poor survival. Wearable devices have been proposed to notify first responders that an OHCA has occurred. However, there are currently no systems that have been validated using real cardiac arrest data. To address this gap, we conducted an observational clinical trial in end-of-life settings to collect data on natural and induced cardiac arrest using wearable technologies. Methods: We recruited individuals across Canada undergoing Medical Assistance In Dying (MAID) procedures, as well as patients in hospice settings. Participants received a consumer grade study watch that collected raw photoplethysmography (PPG) data corresponding to blood volume changes. We completed an interim analysis to describe the cohort, reasons for participation, and assess the feasibility of using this data for algorithm development. We plotted raw PPG values for each participant and used clinical event timelines (time of MAID medication administration, time of respiratory arrest, time of clinician confirmed death) to classify recordings as pulsatile, transitory, or pulseless. Results: From May 1, 2024, to May 1, 2025, 64 individuals were enrolled. 53 met the primary outcome of death while wearing the study watch (82.8%, Table 1). In the MAID arm, all but one case was identified by the same clinician who approached all their community patients during the study period with 34/36 (94.4%) consenting. In the hospice arm, 30/186 (16.1%) patients across three study sites consented. 6 (20%) hospice patients withdrew due to watch discomfort and 5 (16.7%) patients did not wear the watch at time of death. Participants reported an interest in giving back and helping science as motivations for participation (Table 2). Data was successfully obtained from all participants who wore the watch at the time of death. A loss of pulsatile activity was observed for participants that corresponded to clinical event timelines (Figure 1). Conclusion: Wearable-based research in end-of-life settings was feasible and yielded useful data. A clinician advocate was essential for high patient opt-in in the MAID arm. Watch discomfort was a barrier to study continuation in the hospice arm, as the duration of device wear was often several weeks. Ongoing work to train models for cardiac arrest detection is supported by the diversity of this large dataset of pulsatile and pulseless recordings from natural and induced cardiac arrest.

Objective Unplanned return emergency department (ED) visits can reflect clinical deterioration or unmet need from the original visit. We determined the characteristics and outcomes of patients with COVID-19 who return to the ED for COVID-19-related revisits. Methods This retrospective observational study used data for all adult patients visiting 47 Canadian EDs with COVID-19 between 1 March 2020 and 31 March 2022. Multivariable logistic regression assessed the characteristics associated with having a no return visit (SV=single visit group) versus at least one return visit (MV=return visit group) after being discharged alive at the first ED visit. Results 39 809 patients with COVID-19 had 44 862 COVID-19-related ED visits: 35 468 patients (89%) had one visit (SV group) and 4341 (11%) returned to the ED (MV group) within 30 days (mean 2.2, SD=0.5 ED visit). 40% of SV patients and 16% of MV patients were admitted at their first visit, and 41% of MV patients not admitted at their first ED visit were admitted on their second visit. In the MV group, the median time to return was 4 days, 49% returned within 72 hours. In multivariable modelling, a repeat visit was associated with a variety of factors including older age (OR=1.25 per 10 years, 95% CI (1.22 to 1.28)), pregnancy (1.86 (1.46 to 2.36)) and presence of comorbidities (eg, 1.72 (1.40 to 2.10) for cancer, 2.01 (1.52 to 2.66) for obesity, 2.18 (1.42 to 3.36) for organ transplant), current/prior substance use, higher temperature or WHO severe disease (1.41 (1.29 to 1.54)). Return was less likely for females (0.82 (0.77 to 0.88)) and those boosted or fully vaccinated (0.48 (0.34 to 0.70)). Conclusions Return ED visits by patients with COVID-19 within 30 days were common during the first two pandemic years and were associated with multiple factors, many of which reflect known risk for worse outcomes. Future studies should assess reasons for revisit and opportunities to improve ED care and reduce resource use. Trial registration number ClinicalTrials.gov, NCT04702945 .