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Background: For emergency department (ED) patients with cardiac chest pain, introduction of high-sensitivity troponin (hsTnT) pathways has been associated with reductions in length of stay of less than 1 h., Methods: At two urban Canadian sites, we introduced hsTnT on January 26, 2016. While the prior diagnostic algorithm required troponin testing at 0 and 6 h, serial hsTnT serial testing was conducted at 0 and 3 h. We identified consecutive patients who presented with cardiac chest pain from January 1, 2015, to March 31, 2017, along with 30-day outcomes. The primary outcome was a missed 30-day major adverse cardiac event, (MACE) defined as death, revascularization, or readmission for myocardial infarction occurring in a patient-discharged home with a minimizing diagnosis and without cardiac-specific follow-up. Secondary outcomes included admission rate, ED length of stay, and MACE. We compared pre- and post- implementation periods using descriptive methods and repeated this analysis in patients with noncardiac chest pain., Results: We collected 5585 patients with cardiac chest pain, (2678 pre- and 2907 post-introduction) and 434 had (7.8%, 95% CI 7.1 to 8.5%) MACE, with 1 missed MACE. (0.2%, 95% CI 0.04 to 1.3%). Admission rate was stable at 24.1% pre- and 23.7% while median length of stay decreased from 464 to 285 min, a difference of 179 min. (95% CI 61 to 228 min). For 11,611 patients with noncardiac chest pain, admission rate (9%) and length of stay (191 versus 193 min) remained constant., Conclusions: Implementation of hsTnT for evaluation of ED chest pain patients was safe and associated with a 3-h decrease in length of stay., Competing Interests: Declarations Conflict of interest On behalf of all authors, the corresponding author states there is no conflict of interest., (© 2024. The Author(s), under exclusive licence to the Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Aims: A reversible cause of out-of-hospital cardiac arrest (OHCA) is vaguely defined in international guidelines as an identifiable transient or potentially correctable condition. However, studies evaluating long-term outcomes of patients experiencing OHCA due to reversible and non-reversible causes are lacking. We aimed to determine differences in long-term outcomes in OHCA survivors according to different aetiology., Methods and Results: From the British Columbia Cardiac Arrest registry, adults with non-traumatic OHCA (2009-2016) surviving to hospital discharge were identified. Patients were categorized by OHCA aetiology combining reversibility and underlying ischaemic aetiology. The primary outcome was a composite of all-cause mortality, recurrent OHCA, or re-hospitalization for sudden cardiac arrest or ventricular arrhythmias. Using the Kaplan-Meier method and multivariable Cox regression models, we compared the risk of the composite outcome according to different OHCA aetiology. Of 1325 OHCA hospital-discharge survivors (median age 62.8 years, 77.9% male), 431 (32.5%) had reversible ischaemic, 415 (31.3%), non-reversible ischaemic, 99 (7.5%), reversible non-ischaemic, and 380 (28.7%), non-reversible non-ischaemic aetiologies. At 3 years post discharge, the Kaplan-Meier event-free rate was highest in patients with a reversible ischaemic aetiology [91%, 95% confidence interval (CI) 87-94%], and lowest in those with a reversible non-ischaemic aetiology (62%, 95% CI 51-72%). In multivariate analyses, compared with non-reversible non-ischaemic cause, reversible ischaemic cause was associated with a significantly lower hazard ratio (HR; 0.52, 95% CI 0.33-0.81), reversible non-ischaemic cause with a significantly higher HR (1.53, 95% CI 1.03-2.32), and non-reversible ischaemic cause with a non-significant HR (0.92, 95% CI 0.64-1.33) for the composite outcome., Conclusion: Compared to other aetiologies, the presence of a reversible ischaemic cause is associated with improved long-term OHCA outcomes., Competing Interests: Conflict of interest: C.B.F. received consultant fees/honorarium from Bayer, Novo Nordisk, Boehringer Ingelheim, Sanofi, Novartis, New Amsterdam, and HLS therapeutics, and research grants from Bayer, Amgen, and Novartis, all unrelated to the submitted work. K.H.K. received research grants from the Laerdal Foundation, unrelated to the submitted work. All other authors had no conflicts of interest to disclose., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Previous studies have reported race-based health disparities in North America. It is unknown if emergency medical service (EMS) treatment of out-of-hospital cardiac arrest (OHCA) varies based on race. We sought to compare markers of resuscitation intensity among different racial groups., Methods: Using data of adult EMS-treated OHCAs from the Trial of Continuous or Interrupted Chest Compressions During CPR, we analyzed data from participants for whom on-scene return of spontaneous circulation (ROSC) was not achieved. We fit multivariate regression models using a generalized estimating equation, to estimate the association between patient race (White vs. Black vs. "Other") and the following markers for resuscitation intensity: (1) resuscitation attempt duration; (2) intra-arrest transport; (3) number of epinephrine doses; (4) EMS arrival-to-CPR interval, and (5) 9-1-1 to first shock., Results: From our study cohort of 5370 cases, the median age was 65 years old (IQR: 53-78), 2077 (39 %) were women, 2121 (39 %) were Black, 596 (11 %) were "Other race", 2653 (49 %) were White, and 4715 (88 %) occurred in a private location. With reference to White race, Black race was associated with a longer resuscitation attempt duration and a lower number of epinephrine doses; Black and "Other" race were both associated with a lower odds of intra-arrest transport., Conclusion: We identified race-based differences in EMS resuscitation intensity for OHCA within a North American cohort, although 40% of race data was missing from this dataset. Future research investigating race-based differences in OHCA management may be warranted., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Out-of-hospital cardiac arrest (OHCA) is a global health problem affecting approximately 4.4 million individuals yearly. OHCA has a poor survival rate, specifically when unwitnessed (accounting for up to 75% of cases). Rapid recognition can significantly improve OHCA survival, and consumer wearables with continuous cardiopulmonary monitoring capabilities hold potential to "witness" cardiac arrest and activate emergency services. In this study, we used an arterial occlusion model to simulate cardiac arrest and investigated the ability of infrared photoplethysmogram (PPG) sensors, often utilized in consumer wearable devices, to differentiate normal cardiac pulsation, pulseless cardiac (i.e., resembling a cardiac arrest), and non-physiologic (i.e., off-body) states. Across the classification models trained and evaluated on three anatomical locations, higher classification performances were observed on the finger (macro average F1-score of 0.964 on the fingertip and 0.954 on the finger base) compared to the wrist (macro average F1-score of 0.837). The wrist-based classification model, which was trained and evaluated using all PPG measurements, including both high- and low-quality recordings, achieved a macro average precision and recall of 0.922 and 0.800, respectively. This wrist-based model, which represents the most common form factor in consumer wearables, could only capture about 43.8% of pulseless events. However, models trained and tested exclusively on high-quality recordings achieved higher classification outcomes (macro average F1-score of 0.975 on the fingertip, 0.973 on the finger base, and 0.934 on the wrist). The fingertip model had the highest performance to differentiate arterial occlusion pulselessness from normal cardiac pulsation and off-body measurements with macro average precision and recall of 0.978 and 0.972, respectively. This model was able to identify 93.7% of pulseless states (i.e., resembling a cardiac arrest event), with a 0.4% false positive rate. All classification models relied on a combination of time-, power spectral density (PSD)-, and frequency-domain features to differentiate normal cardiac pulsation, pulseless cardiac, and off-body PPG recordings. However, our best model represented an idealized detection condition, relying on ensuring high-quality PPG data for training and evaluation of machine learning algorithms. While 90.7% of our PPG recordings from the fingertip were considered of high quality, only 53.2% of the measurements from the wrist passed the quality criteria. Our findings have implications for adapting consumer wearables to provide OHCA detection, involving advancements in hardware and software to ensure high-quality measurements in real-world settings, as well as development of wearables with form factors that enable high-quality PPG data acquisition more consistently. Given these improvements, we demonstrate that OHCA detection can feasibly be made available to anyone using PPG-based consumer wearables., (© 2024. The Author(s).)

Background: It is unclear how invasive resuscitative protocols may impact the time-dependent prognosis of out-of-hospital cardiac arrest (OHCA) resuscitations, or the relationship between intra-arrest transport and outcomes., Methods: We performed a secondary analysis of the Prague OHCA Study, which randomized refractory OHCAs to "invasive" (intra-arrest transport for possible ECPR initiation) vs. "standard" resuscitation strategies (predominantly performed on-scene). Between groups, we compared outcomes of the initial resuscitation and 180- and 30-day favourable neurological outcomes (CPC 1-2), and within categories based on resuscitation duration (collapse-to-ROSC/ECPR interval). We plotted the dynamic probability of favourable outcomes with increasing durations of unsuccessful resuscitation., Results: Among invasive and standard groups, respectively: 34/124 (27%) vs. 58/132 (44%) had sustained ROSC (difference -17%, 95%CI -5.0, -28); 38/124 (31%) vs. 24/132 (18%) had 30-day favourable neurological outcomes (difference 12%; 95%CI 2.0, 23); and 39/124 (31%) vs. 29/132 (22%) had 180-day favourable neurological outcomes (difference 9.5%; 95%CI -1.3, 20). For favourable outcome cases: standard group resuscitation durations were right-skewed within the first 60 min; for the invasive group the distribution was bimodal, extending to 77 min. For invasive- and standard-treated cases, the probability of favourable outcomes among those in refractory arrest at 30 min was 28% and 7.6%, respectively; declining to 0% at 77 and 60 min., Conclusion: In comparison to standard resuscitation, invasive strategy cases had fewer achieve sustained ROSC, however improved overall 30-day favourable neurological outcomes. While standard resuscitation yield was limited to < 60 min, invasive protocols offer a second extended window of potential successful resuscitation., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Belohlavek reports having received lecture honoraria from the Getinge and Resuscitec Companies., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Aim: While intravenous (IV) vascular access for out-of-hospital cardiac arrest (OHCA) resuscitation is standard, humeral-intraosseous (IO) access is commonly used, despite few supporting data. We investigated the association between IV vs. humeral-IO and outcomes., Methods: We utilized BC Cardiac Arrest Registry data, including adult OHCA where the first-attempted intra-arrest vascular access route performed by advanced life support (ALS)-trained paramedics was IV or humeral-IO. We fit a propensity-score adjusted model with inverse probability treatment weighting to estimate the association between IV vs. humeral-IO routes and favorable neurological outcomes (CPC 1-2) and survival at hospital discharge. We repeated models within subgroups defined by initial cardiac rhythm., Results: We included 2,112 cases; the first-attempted route was IV (n = 1,575) or humeral-IO (n = 537). Time intervals from ALS-paramedic on-scene arrival to vascular access (6.6 vs. 6.9 min) and epinephrine administration (9.0 vs. 9.3 min) were similar between IV and IO groups, respectively. Among IV and humeral-IO groups, 98 (6.2%) and 20 (3.7%) had favorable neurological outcomes. Compared to humeral-IO, an IV-first approach was associated with improved hospital-discharge favorable neurological outcomes (AOR 1.7; 95% CI 1.1-2.7) and survival (AOR 1.5; 95% CI 1.0-2.3). Among shockable rhythm cases, an IV-first approach was associated with improved favorable neurological outcomes (AOR 4.2; 95% CI 2.1-8.2), but not among non-shockable rhythm cases (AOR 0.73; 95% CI 0.39-1.4)., Conclusion: An IV-first approach, compared to humeral-IO, for intra-arrest resuscitation was associated with an improved odds of favorable neurological outcomes and survival to hospital discharge. This association was seen among an initial shockable rhythm, but not non-shockable rhythm, subgroups., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: We aimed to estimate the effect of extracorporeal cardiopulmonary resuscitation (ECPR) on neurological outcome and mortality, when compared to conventional cardiopulmonary resuscitation (CCPR), using an individual patient data meta-analysis (IPDMA)., Methods: A systematic literature search was performed up to the 20th of October 2022 in the PubMed, EMBASE and CENTRAL databases. For observational studies with unmatched populations, a propensity score including age, location of arrest and initial rhythm was used to match ECPR and CCPR patients in a 1:1 ratio. The primary and secondary outcomes were unfavorable neurological outcome (Cerebral Performance Category of 3-5) and mortality, respectively, which were both collected at different time-points., Results: Data from 17 studies, including 2064 matched cardiac arrest (CA) patients (1031 ECPR and 1033 CCPR cases) were included. In comparison to CCPR, ECPR was associated with a decreased odds of unfavorable neurological outcome (847, 82.2% vs. 897, 86.8% - OR 0.68 [95%CI 0.53-0.87]; p = 0.002) and death (803, 77.9% vs. 860, 83.3% - OR 0.68 [95%CI 0.54-0.86]; p = 0.001). These results were consistent across most of the prespecified subgroups. Moreover, the odds of both unfavorable neurological outcome and mortality were significantly influenced by initial rhythm, cause of arrest and combinations of lactate levels on admission and duration of resuscitation., Conclusions: This IPDMA showed that ECPR was associated with significantly lower rates of unfavorable neurological outcome and mortality in refractory CA. The overall effect could be influenced by CA characteristics and the severity of the initial injury., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ‘A Cariou reported receiving lecture fees from BD; FS Taccone received lecture fees from BD and ZOLL and is scientific advisor for Nihon Khoden, Neuroptics and Eurosets. Other authors reported no potential conflict of interest relevant to this study.’., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Clinicians may make prognostication decisions for out-of-hospital cardiac arrest (OHCA) using historical details pertaining to non-prescription drug use. However, differences in outcomes between OHCAs with evidence of non-prescription drug use, compared to other OHCAs, have not been well described., Methods: We included emergency medical service-treated OHCA in the British Columbia Cardiac Arrest Registry (January/2019-June/2023). We classified cases as "non-prescription drug-associated cardiac arrests" (DA-OHCA) if there was evidence of non-prescription drug use preceding the OHCA, including witness accounts of use within 24 h or paraphernalia at the scene. We fit logistic regression models to investigate the association between DA-OHCA (vs. other cases) and favourable neurological outcome (Cerebral Performance Category [CPC] 1-2) and survival at hospital discharge, and return of spontaneous circulation (ROSC)., Results: Of 18,426 OHCA, 2,171 (12%) were classified as DA-OHCA. DA-OHCA tended to be younger, unwitnessed, occur during the evening or night, and present with a non-shockable rhythm, compared to other OHCA. DA-OHCA (221 [10%]) had a greater proportion (difference 1.8%; 95% CI 0.49-3.2) with favourable neurological outcomes compared to other OHCA (1,365 [8.4%]). Adjusted models did not identify an association of DA-OHCA with favourable neurological outcome (OR 1.08, 95% CI 0.87-1.33) or survival to hospital discharge (OR 1.13, 95% CI 0.93-1.38), but did demonstrate an association with ROSC (OR 1.13, 95% CI 1.004-1.27)., Conclusion: In unadjusted models, DA-OHCA was associated with an improved odds of survival and favourable neurological outcomes at hospital discharge, compared to other OHCA. However, we did not detect an association in adjusted analyses., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objectives: When an out-of-hospital cardiac arrest (OHCA) occurs, the first step in the chain of survival is detection. However, 75% of OHCAs are unwitnessed, representing the largest barrier to activating the chain of survival. Wearable devices have the potential to be "artificial bystanders," detecting OHCA and alerting 9-1-1. We sought to understand factors impacting users' willingness for continuous use of a wearable device through an online survey to inform future use of these systems for automated OHCA detection., Methods: Data were collected from October 2022 to June 2023 through voluntary response sampling. The survey investigated user convenience and perception of urgency to understand design preferences and willingness to adhere to continuous wearable use across different hypothetical risk levels. Associations between categorical variables and willingness were evaluated through nonparametric tests. Logistic models were fit to evaluate the association between continuous variables and willingness at different hypothetical risk levels., Results: The survey was completed by 359 participants. Participants preferred hand-based devices (wristbands: 87%, watches: 86%, rings: 62%) and prioritized comfort (94%), cost (83%), and size (72%). Participants were more willing to adhere at higher levels of hypothetical risk. At the baseline risk of 0.1%, older individuals with prior wearable use were most willing to adhere to continuous wearable use., Conclusion: Individuals were willing to continuously wear wearable devices for OHCA detection, especially at increased hypothetical risk of OHCA. Optimizing willingness is not just a matter of adjusting for user preferences, but also increasing perception of urgency through awareness and education about OHCA., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Journal of the American College of Emergency Physicians Open published by Wiley Periodicals LLC on behalf of American College of Emergency Physicians.)

Purpose: Insufficient evidence-based recommendations to guide care for patients with devastating brain injuries (DBIs) leave patients vulnerable to inconsistent practice at the emergency department (ED) and intensive care unit (ICU) interface. We sought to characterize the beliefs of Canadian emergency medicine (EM) and critical care medicine (CCM) physician site directors regarding current management practices for patients with DBI., Methods: We conducted a cross-sectional survey of EM and CCM physician directors of adult EDs and ICUs across Canada (December 2022 to March 2023). Our primary outcome was the proportion of respondents who manage (or consult on) patients with DBI in the ED. We conducted subgroup analyses to compare beliefs of EM and CCM physicians., Results: Of 303 eligible respondents, we received 98 (32%) completed surveys (EM physician directors, 46; CCM physician directors, 52). Most physician directors reported participating in the decision to withdraw life-sustaining measures (WLSM) for patients with DBI in the ED (80%, n = 78), but 63% of these (n = 62) said this was infrequent. Physician directors reported that existing neuroprognostication methods are rarely sufficient to support WLSM in the ED (49%, n = 48) and believed that an ICU stay is required to improve confidence (99%, n = 97). Most (96%, n = 94) felt that providing caregiver visitation time prior to WLSM was a valid reason for ICU admission., Conclusion: In our survey of Canadian EM and CCM physician directors, 80% participated in WLSM in the ED for patients with DBI. Despite this, most supported ICU admission to optimize neuroprognostication and patient-centred end-of-life care, including organ donation., (© 2024. The Author(s).)

Setting: In Canada's federated healthcare system, 13 provincial and territorial jurisdictions have independent responsibility to collect data to inform health policies. During the COVID-19 pandemic (2020-2023), national and regional sero-surveys mostly drew upon existing infrastructure to quickly test specimens and collect data but required cross-jurisdiction coordination and communication., Intervention: There were 4 national and 7 regional general population SARS-CoV-2 sero-surveys. Survey methodologies varied by participant selection approaches, assay choices, and reporting structures. We analyzed Canadian pandemic sero-surveillance initiatives to identify key learnings to inform future pandemic planning., Outcomes: Over a million samples were tested for SARS-CoV-2 antibodies from 2020 to 2023 but siloed in 11 distinct datasets. Most national sero-surveys had insufficient sample size to estimate regional prevalence; differences in methodology hampered cross-regional comparisons of regional sero-surveys. Only four sero-surveys included questionnaires. Sero-surveys were not directly comparable due to different assays, sampling methodologies, and time-frames. Linkage to health records occurred in three provinces only. Dried blood spots permitted sample collection in remote populations and during stay-at-home orders., Implications: To provide timely, high-quality information for public health decision-making, routine sero-surveillance systems must be adaptable, flexible, and scalable. National capability planning should include consortiums for assay design and validation, defined mechanisms to improve test capacity, base documents for data linkage and material transfer across jurisdictions, and mechanisms for real-time communication of data. Lessons learned will inform incorporation of a robust sero-survey program into routine surveillance with strategic sampling and capacity to adapt and scale rapidly as a part of a comprehensive national pandemic response plan., (© 2024. The Author(s) under exclusive license to The Canadian Public Health Association.)

Objectives The coronavirus disease 2019 (COVID-19) pandemic has impacted public health systems and individuals' behaviour, with decreasing survival rates among out-of-hospital cardiac arrest (OHCA) patients. Bystander cardiopulmonary resuscitation (CPR) improves OHCA outcomes, which may have been affected by COVID-19. We sought to understand the impacts of COVID-19 on bystanders' willingness to administer CPR in three Canadian provinces. Methods Participants ≥ 18 years of age were surveyed online about their current and recalled pre-pandemic attitudes toward CPR and perceived transmission risk. We compared mean willingness to perform various CPR actions before and during the pandemic using paired t-tests. Differences in willingness across three provinces were assessed using analysis of variance (ANOVA) and Tukey's Honestly Significant Difference (HSD) test. We also conducted Chi-square tests to assess changes in willingness to perform CPR on children and older adults. Results Five hundred thirty-five participants were surveyed from October 1 to November 15, 2021. The mean age was 42.7 years (SD 14.5), and 60.2% were female. Participants reported less willingness to perform chest compressions on strangers during the pandemic compared to their recollections before the pandemic (mean willingness 86.2% vs. 94.3% prior, p<0.001). With personal protective equipment (PPE) available, particularly masks, willingness recovered to 91.3% (p<0.001). Willingness was higher in Nova Scotia (NS) than in British Columbia (BC) or Ontario (ON). Reluctance to assist older adults increased from 6.6% to 12.0% (p=0.020). Conclusions This study highlights changes in CPR willingness during the COVID-19 pandemic, underscoring the importance of PPE and offering insights into public health strategies pertaining to CPR during a pandemic., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Research Ethics Board of the University of British Columbia issued approval H21-02624. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: John Sapp declare(s) a grant and personal fees from Abbott, Johnson and Johnson, Medtronic, Varian. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Shadarevian et al.)

Importance: For pediatric out-of-hospital cardiac arrest (OHCA), emergency medical services (EMS) may elect to transport to the hospital during active cardiopulmonary resuscitation (CPR) (ie, intra-arrest transport) or to continue on-scene CPR for the entirety of the resuscitative effort. The comparative effectiveness of these strategies is unclear., Objective: To evaluate the association between intra-arrest transport compared with continued on-scene CPR and survival after pediatric OHCA, and to determine whether this association differs based on the timing of intra-arrest transport., Design, Setting, and Participants: This cohort study included pediatric patients aged younger than 18 years with EMS-treated OHCA between December 1, 2005 and June 30, 2015. Data were collected from the Resuscitation Outcomes Consortium Epidemiologic Registry, a prospective 10-site OHCA registry in the US and Canada. Data analysis was performed from May 2022 to February 2024., Exposures: Intra-arrest transport, defined as an initiation of transport prior to the return of spontaneous circulation, and the interval between EMS arrival and intra-arrest transport., Main Outcomes and Measures: The primary outcome was survival to hospital discharge. Patients who underwent intra-arrest transport at any given minute after EMS arrival were compared with patients who were at risk of undergoing intra-arrest transport within the same minute using time-dependent propensity scores calculated from patient demographics, arrest characteristics, and EMS interventions. We examined subgroups based on age (<1 year vs ≥1 year)., Results: Of 2854 eligible pediatric patients (median [IQR] age, 1 [0-9] years); 1691 males [59.3%]) who experienced OHCA between December 2005 and June 2015, 1892 children (66.3%) were treated with intra-arrest transport and 962 children (33.7%) received continued on-scene CPR. The median (IQR) time between EMS arrival and intra-arrest transport was 15 (9-22) minutes. In the propensity score-matched cohort (3680 matched cases), there was no significant difference in survival to hospital discharge between the intra-arrest transport group and the continued on-scene CPR group (87 of 1840 patients [4.7%] vs 95 of 1840 patients [5.2%]; risk ratio [RR], 0.81 [95% CI, 0.59-1.10]). Survival to hospital discharge was not modified by the timing of intra-arrest transport (P value for the interaction between intra-arrest transport and time to matching = .10). Among patients aged younger than 1 year, intra-arrest transport was associated with lower survival to hospital discharge (RR, 0.52; 95% CI, 0.33-0.83) but there was no association for children aged 1 year or older (RR, 1.22; 95% CI, 0.77-1.93)., Conclusions and Relevance: In this cohort study of a North American OHCA registry, intra-arrest transport compared with continued on-scene CPR was not associated with survival to hospital discharge among children with OHCA. However, intra-arrest transport was associated with a lower likelihood of survival to hospital discharge among children aged younger than 1 year.

Out-of-hospital cardiac arrest (OHCA) is a major health problem, with a poor survival rate of 2-11%. For the roughly 75% of OHCAs that are unwitnessed, survival is approximately 2-4.4%, as there are no bystanders present to provide life-saving interventions and alert Emergency Medical Services. Sensor technologies may reduce the number of unwitnessed OHCAs through automated detection of OHCA-associated physiological changes. However, no technologies are widely available for OHCA detection. This review identifies research and commercial technologies developed for cardiopulmonary monitoring that may be best suited for use in the context of OHCA, and provides recommendations for technology development, testing, and implementation. We conducted a systematic review of published studies along with a search of grey literature to identify technologies that were able to provide cardiopulmonary monitoring, and could be used to detect OHCA. We searched MEDLINE, EMBASE, Web of Science, and Engineering Village using MeSH keywords. Following inclusion, we summarized trends and findings from included studies. Our searches retrieved 6945 unique publications between January, 1950 and May, 2023. 90 studies met the inclusion criteria. In addition, our grey literature search identified 26 commercial technologies. Among included technologies, 52% utilized electrocardiography (ECG) and 40% utilized photoplethysmography (PPG) sensors. Most wearable devices were multi-modal (59%), utilizing more than one sensor simultaneously. Most included devices were wearable technologies (84%), with chest patches (22%), wrist-worn devices (18%), and garments (14%) being the most prevalent. ECG and PPG sensors are heavily utilized in devices for cardiopulmonary monitoring that could be adapted to OHCA detection. Developers seeking to rapidly develop methods for OHCA detection should focus on using ECG- and/or PPG-based multimodal systems as these are most prevalent in existing devices. However, novel sensor technology development could overcome limitations in existing sensors and could serve as potential additions to or replacements for ECG- and PPG-based devices., (© 2024. The Author(s) under exclusive licence to Biomedical Engineering Society.)

This study investigated the association between previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and risk of symptoms associated with post-COVID conditions among fully vaccinated paramedics in Canada. We included vaccinated paramedics who provided blood sample and questionnaire data on the same date during the study period. We examined the presence of symptoms associated with post-COVID conditions and depression severity against prior SARS-CoV-2 infection categories. Compared to the "no previous SARS-CoV-2 infection" group, there was no detected association between known prior SARS-CoV-2 infection (odds ratio [OR], 1.42 [95% confidence interval {CI}, 0.96-2.09]), nor unknown prior SARS-CoV-2 infection (OR, 0.54 [95% CI, 0.29-1.00]), and the presence of symptoms associated with post-COVID conditions., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Aims: The Medical Priority Dispatch System (MPDS)® is used to triage 9-1-1 calls according to acuity, with certain coding receiving telecommunicator cardiopulmonary resuscitation (T-CPR) for suspected out-of-hospital cardiac arrest (OHCA). However, this may be challenging for those with drug poisoning emergencies, who may resemble OHCA. We sought to examine the performance of the system to correctly identify cases requiring T-CPR, specifically at overdose prevention services (OPS)., Methods: This retrospective cohort study included patients attended by the provincial emergency medical system (EMS) (May 1, 2019-January 31, 2023). We calculated the diagnostic performance of MPDS® assessment of whether the case required T-CPR instructions against the gold standard of whether the patient was found pulseless on EMS clinician arrival. We compared performance among subgroups, specifically OPS vs other locations and drug poisoning-classified cases vs other case classifications., Results: Comparing OPS to other locations, the sensitivity of MPDS ® was similar (66.7% vs 62.4%, p  = 0.4), with lower specificity (87.3% vs 98.1%, p  < 0.01) and positive predictive value (0.3% vs 35.7%, p  < 0.01) and higher negative predictive value (99.9% vs 99.4%, p  < 0.01). The negative likelihood ratio of MPDS ® was 0.381 at OPS locations, compared with 0.383 at other locations, while the positive likelihood ratio was 5.24, compared with 32.36. In patients with drug poisoning emergencies, compared with other 9-1-1 events, MPDS ® had higher sensitivity (83.6% vs 60.6%, p  < 0.01) but lower specificity (77.6% vs 98.9%, p  < 0.01) and positive predictive value (10.5% vs 48.5%, p  < 0.01), and similar negative predictive value (99.33% vs 99.35%, p  = 0.03). The negative likelihood ratio of MPDS® was 0.212 in drug poisoning emergencies compared with 0.398 for all other presentations, and the positive likelihood ratio was 3.73 compared with 57.88., Discussion and Conclusions: The ability of MPDS ® to correctly identify patients needing telecommunicator cardiopulmonary resuscitation instructions differed between OPS settings and other locations, frequently recommending T-CPR for patients not suffering OHCA at an OPS. Different strategies developed in collaboration with people who use substances are required to better tailor dispatch instructions prior to EMS arrival to avoid delays in life-saving interventions.

Recent research has highlighted the Omicron variant's capacity to evade immune protection conferred by wild-type (WT) mRNA vaccines. Despite this observation, the potential involvement of antigenic sin phenomena remains unclear. Our hypothesis posited that a greater number of prior WT vaccine doses might lead to reduced anti-Omicron neutralization Abs following Omicron infection. To investigate this, we analyzed blood samples from human participants in the COVID-19 Occupational Risk, Seroprevalence, and Immunity among Paramedics (CORSIP) study who had received at least one WT mRNA vaccine before contracting Omicron. The exposure variable was the number of WT mRNA vaccines administered, and the outcome was the angiotensin-converting enzyme 2 (ACE-2) percent inhibition specific to the BA.4/BA.5 Omicron Ag. Contrary to expectations, our findings revealed that more WT-based vaccines were associated with an enhanced Omicron-specific immune response., (Copyright © 2024 The Authors.)

Background: The impact of extreme heat on out-of-hospital cardiac arrest (OHCA) incidence and outcomes is under-studied. We investigated OHCA incidence and outcomes over increasing temperatures., Methods: We included non-traumatic EMS (Emergency Medical Services)-assessed OHCAs in British Columbia during the warm seasons of 2020-2021. We fit a time-series quasi-Poisson generalized linear model to estimate the association between temperature and incidence of both EMS-assessed, EMS-treated, and EMS-untreated OHCAs. Second, we employed a logistic regression model to estimate the association between "heatwave" periods (defined as a daily mean temperature > 99th percentile for ≥ 2 consecutive days, plus 3 lag days) with survival and favourable neurological outcomes (cerebral performance category ≤ 2) at hospital discharge., Results: Of 5478 EMS-assessed OHCAs, 2833 were EMS-treated. OHCA incidence increased with increasing temperatures, especially exceeding a daily mean temperature of 25 °C Compared to the median daily mean temperature (16.9 °C), the risk of EMS-assessed (relative risk [RR] 3.7; 95%CI 3.0-4.6), EMS-treated (RR 2.9; 95%CI 2.2-3.9), and EMS-untreated (RR 4.3; 95%CI 3.2-5.7) OHCA incidence were higher during days with a temperature over the 99th percentile. Of EMS-treated OHCAs, during the heatwave (n = 179) and non-heatwave (n = 2654) periods, 4 (2.2%) and 270 (10%) survived and 4 (2.2%) and 241 (9.2%) had favourable neurological outcomes, respectively. Heatwave period OHCAs had decreased odds of survival (adjusted OR 0.28; 95%CI 0.10-0.79) and favourable neurological outcome (adjusted OR 0.31; 95%CI 0.11-0.89) at hospital discharge, compared to other periods., Conclusion: Extreme heat was associated with a higher incidence of OHCA, and lower odds of survival and favourable neurological status at hospital discharge., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Background: Multiple jurisdictions reported a significant increase in out-of-hospital cardiac arrest (OHCA) incidence over the past decade, however the reasons for this remain unclear. We investigated how drug-associated OHCA (DA-OHCA) contributed to overall OHCA incidence, and whether the likelihood of treatment by emergency medical services (EMS) was associated with DA-OHCA classification., Methods: Using a large provincial cardiac arrest registry, we included consecutive, non-traumatic adult OHCA from 2016-2022. We classified as drug-associated if there were historical accounts of non-prescription drug use within the preceding 24 hours or evidence of paraphernalia at the scene. We examined year-by-year trends in OHCA and DA-OHCA incidence. We also investigated the association between DA-OHCA and odds of EMS treatment using an adjusted logistic regression model., Results: Of 33,365 EMS-assessed cases, 1,985/18,591 (11%) of EMS-treated OHCA and 887/9,200 (9.6%) of EMS-untreated OHCA were DA-OHCA. Of EMS-treated DA-OHCA, the median age was 40 years (IQR 31-51), 1,059 (53%) had a known history of non-prescription drug use, and 570 (29%) were public-location. From 2016 to 2022, EMS-treated OHCA incidence increased from 60 to 79 per 100,000 person-years; EMS-treated DA-OHCA incidence increased from 3.7 to 9.1 per 100,000 person-years. The proportion of overall OHCA classified as DA-OHCA increased from 6.1% to 11.5%. DA-OHCA was associated with greater odds of EMS treatment (AOR 1.34; 95%CI 1.13-1.58)., Conclusion: Although EMS-treated DA-OHCA incidence increased by nearly three-fold, it comprised a minority of the overall OHCA increase during the study period. DA-OHCA was associated with an increased likelihood of EMS treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: The prognostic association between dysnatremia and outcomes in out-of-hospital cardiac arrest (OHCA) is not well understood. Given hypernatremia is associated with poor outcomes in critical illness and hyponatremia may exacerbate cerebral edema, we hypothesized that dysnatremia on OHCA hospital admission would be associated with worse neurological outcomes., Methods: We studied adults (≥19 years) with non-traumatic OHCA between 2009 and 2016 who were enrolled in the British Columbia Cardiac Arrest Registry and survived to hospital admission at 2 quaternary urban hospitals. We stratified cases by admission serum sodium into hyponatremic (<135 mmol/L), normonatremic (135-145 mmol/L), and hypernatremic (>145 mmol/L) groups. We used logistic regression models, adjusted for age, sex, shockable rhythm, admission serum lactate, and witnessed arrest, to estimate the association between admission sodium and favorable neurological outcome (cerebral performance category 1-2 or modified Rankin scale 0-3)., Results: Of 414 included patients, 63 were hyponatremic, 330 normonatremic, and 21 hypernatremic. In each respective group, 21 (33.3%), 159 (48.2%), and 3 (14.3%) experienced good neurological outcomes. In univariable models, hyponatremia (OR 0.53, 95% CI 0.30-0.93) and hypernatremia (OR 0.19, 95% CI 0.05-0.65) were associated with lower odds of good neurological outcomes compared to the normonatremia group. After adjustment, only hypernatremia was associated with lower odds of good neurological outcomes (OR 0.22, 95% CI 0.05-0.98)., Conclusions: Hypernatremia at admission was independently associated with decreased probability of good neurological outcomes at discharge post-OHCA. Future studies should focus on elucidating the pathophysiology of dysnatremia following OHCA., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Objectives: Bystander-applied Automated External Defibrillators (AED) improve outcomes for out-of-hospital cardiac arrest. AED placement is often driven by private enterprise or non-for-profit agencies, which may result in inequitable access. We sought to compare AED availability between four regions in British Columbia (BC)., Methods: We identified AEDs (confirmed to be operational) and emergency medical system (EMS)-treated out-of-hospital cardiac arrests (OHCA) from provincial registries. We compared AED availability between BC's four most populous regions. The primary outcome was the total regional weekly accessible AED-hours per 100,000 population. We also examined: AEDs per 100,000 population and per km 2 , the ratio of AEDs to OHCA, and the distance from each OHCA to the closest AED., Results: From provincial registries, we included 879 AEDs from BC's four most populous regions, where 9333 EMS-treated OHCA occurred over a 5-year period. The most common AED location types were stores, public community centres, and office buildings. Ten percent of AEDs were accessible for all hours. Weekly accessible AED-hours/100,000 population in the four regions were: 3845, 1734, 1594, and 1299. AEDs/100,000 population ranged from 22 to 48, and AEDs/km 2 ranged from 0.0048 to 0.20. The number of OHCAs per AED per year ranged from 1.1 to 2.8. The median OHCA-to-closest AED distance ranged from 503 (IQR 244, 947) to 925 (IQR 455, 1501) metres. The regional mean accessibility of individual AEDs ranged between 59 and 79 h per week., Conclusion: BC's four most populous regions demonstrate substantial variability in AED accessibility. Further benefit could be derived from AEDs if placed in locations accessible all hours. Our data may encourage community planning efforts to use data-based strategies to systematically place AEDs in optimal locations with strategies to maximize accessibility., (© 2023. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

Aim: We sought to describe the impact of the COVID-19 pandemic on the care provided by Canadian emergency medical system (EMS) clinicians to patients suffering out of hospital cardiac arrest (OHCA), and whether any observed changes persisted beyond the initial phase of the pandemic., Methods: We analysed cases of adult, non-traumatic, OHCA from the Canadian Resuscitation Outcome Consortium (CanROC) registry who were treated between January 27th, 2018, and December 31st, 2021. We used adjusted regression models and interrupted time series analysis to examine the impact of the COVID-19 pandemic (January 27th, 2020 - December 31st, 2021)on the care provided to patients with OHCA by EMS clinicians., Results: There were 12,947 cases of OHCA recorded in the CanROC registry in the pre-COVID-19 period and 17,488 during the COVID-19 period. We observed a reduction in the cumulative number of defibrillations provided by EMS (aRR 0.91, 95% CI 0.89 - 0.93, p < 0.01), a reduction in the odds of attempts at intubation (aOR 0.33, 95% CI 0.31 - 0.34, p < 0.01), higher rates of supraglottic airway use (aOR 1.23, 95% CI 1.16-1.30, p < 0.01), a reduction in vascular access (aOR for intravenous access 0.84, 95% CI 0.79 - 0.89, p < 0.01; aOR for intraosseous access 0.89, 95% CI 0.82 - 0.96, p < 0.01), a reduction in the odds of epinephrine administration (aOR 0.89, 95% CI 0.85 - 0.94, p < 0.01), and higher odds of resuscitation termination on scene (aOR 1.38, 95% CI 1.31 - 1.46, p < 0.01). Delays to initiation of chest compressions (2 min. vs. 3 min., p < 0.01), intubation (16 min. vs. 19 min., p = 0.01), and epinephrine administration (11 min. vs. 13 min., p < 0.01) were observed, whilst supraglottic airways were inserted earlier (11 min. vs. 10 min., p < 0.01)., Conclusion: The COVID-19 pandemic was associated with substantial changes in EMS management of OHCA. EMS leaders should consider these findings to optimise current OHCA management and prepare for future pandemics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Aim: Humeral and tibial intraosseous (IO) vascular access can deliver resuscitative medications for out-of-hospital cardiac arrest (OHCA), however the optimal site is unclear. We examined the association between IO tibia vs. humerus as the first-attempted vascular access site with OHCA outcomes., Methods: We used prospectively-collected data from the British Columbia Cardiac Arrest registry, including adult OHCAs treated with IO humerus or IO tibia as the first-attempted intra-arrest vascular access. We fit logistic regression models on the full study cohort and a propensity-matched cohort, to estimate the association between IO site and both favorable neurological outcomes (Cerebral Performance Category 1-2) and survival at hospital discharge., Results: We included 1041 (43%) and 1404 (57%) OHCAs for whom IO humerus and tibia, respectively, were the first-attempted intra-arrest vascular access. Among humerus and tibia cases, 1010 (97%) and 1369 (98%) had first-attempt success, and the median paramedic arrival-to-successful access interval was 6.7 minutes (IQR 4.4-9.4) and 6.1 minutes (IQR 4.1-8.9), respectively. In the propensity-matched cohort (n = 2052), 31 (3.0%) and 44 (4.3%) cases had favourable neurological outcomes in the IO humerus and IO tibia groups, respectively; compared to IO humerus, we did not detect an association between IO tibia with favorable neurological outcomes (OR 1.44; 95% CI 0.90-2.29) or survival to hospital discharge (OR 1.29; 95% CI 0.83-2.01). Results using the full cohort were similar., Conclusions: We did not detect an association between the first-attempted intra-arrest IO site (tibia vs. humerus) and clinical outcomes. Clinical trials are warranted to test differences between vascular access strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Advances in vertical take-off and landing (VTOL) technologies may enable drone-like crewed air ambulances to rapidly respond to out-of-hospital cardiac arrest (OHCA) in urban areas. We estimated the impact of incorporating VTOL air ambulances on OHCA response intervals in two large urban centres in France and Canada., Methods: We included adult OHCAs occurring between Jan. 2017-Dec. 2018 within Greater Paris in France and Metro Vancouver in Canada. Both regions utilize tiered OHCA response with basic (BLS)- and advanced life support (ALS)-capable units. We simulated incorporating 1-2 ALS-capable VTOL air ambulances dedicated to OHCA response in each study region, and computed time intervals from call reception by emergency medical services (EMS) to arrival of the: (1) first ALS unit ("call-to-ALS arrival interval"); and (2) first EMS unit ("call-to-first EMS arrival interval")., Results: There were 6,217 OHCAs included during the study period (3,760 in Greater Paris and 2,457 in Metro Vancouver). Historical median call-to-ALS arrival intervals were 21 min [IQR 16-29] in Greater Paris and 12 min [IQR 9-17] in Metro Vancouver, while median call-to-first EMS arrival intervals were 11 min [IQR 8-14] and 7 min [IQR 5-8] respectively. Incorporating 1-2 VTOL air ambulances improved median call-to-ALS arrival intervals to 7-9 min and call-to-first EMS arrival intervals to 6-8 min in both study regions (all P < 0.001)., Conclusion: VTOL air ambulances dedicated to OHCA response may improve EMS response intervals, with substantial improvements in ALS response metrics., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Prof. Alain Cariou is a member of the Resuscitation’s editorial board. All authors declare no conflict of interest with any of the two VTOL companies cited in this work (Urban Aero or Volocopter).]., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: We examined the 11 month longitudinal antibody decay among two-dose mRNA vaccinees, and identified factors associated with faster decay., Methods: The study included samples from the COVID-19 Occupational Risk, Seroprevalence and Immunity among Paramedics (CORSIP) longitudinal observational study of paramedics in Canada. Participants were included if they had received two mRNA vaccines without prior SARS-CoV-2 infection and provided two blood samples post-vaccination. The outcomes of interest were quantitative SARS-CoV-2 antibody concentrations. We employed spaghetti and scatter plots (with kernel-weighted local polynomial smoothing curve) to describe the trend of the antibody decay over 11 months post-vaccine and fit a mixed effect exponential decay model to examine the loss of immunogenicity and factors associated with antibody waning over time., Results: This analysis included 652 blood samples from 326 adult paramedics. Total anti-spike antibody levels peaked on the twenty-first day (antibody level 9042 U ml -1 ) after the second mRNA vaccine dose. Total anti-spike antibody levels declined thereafter, with a half-life of 94 [95 % CI: 70, 143] days, with levels plateauing at 295 days (antibody level 1021 U ml -1 ). Older age, vaccine dosing interval <35 days, and the BNT162b2 vaccine (compared to mRNA-1273 vaccine) were associated with faster antibody decay., Conclusion: Antibody levels declined after the initial mRNA series with a half-life of 94 days, plateauing at 295 days. These findings may inform the timing of booster vaccine doses and identifying individuals with faster antibody decay., Competing Interests: The authors declare no conflict of interest., (© 2023 The Authors.)

The coronavirus disease 2019 (COVID-19) pandemic, caused by the SARS-CoV-2 virus, has rapidly evolved since late 2019, due to highly transmissible Omicron variants. While most Canadian paramedics have received COVID-19 vaccination, the optimal ongoing vaccination strategy is unclear. We investigated neutralizing antibody (NtAb) response against wild-type (WT) Wuhan Hu-1 and Omicron BA.4/5 lineages based on the number of doses and past SARS-CoV-2 infection, at 18 months post-initial vaccination (with a Wuhan Hu-1 platform mRNA vaccine [BNT162b2 or mRNA-1273]). Demographic information, previous COVID-19 vaccination, infection history, and blood samples were collected from paramedics 18 months post-initial mRNA COVID-19 vaccine dose. Outcome measures were ACE2 percent inhibition against Omicron BA.4/5 and WT antigens. We compared outcomes based on number of vaccine doses (two vs. three) and previous SARS-CoV-2 infection status, using the Mann-Whitney U test. Of 657 participants, the median age was 40 years (IQR 33-50) and 251 (42 %) were females. Overall, median percent inhibition to BA.4/5 and WT was 71.61 % (IQR 39.44-92.82) and 98.60 % (IQR 83.07-99.73), respectively. Those with a past SARS-CoV-2 infection had a higher median percent inhibition to BA.4/5 and WT, when compared to uninfected individuals overall and when stratified by two or three vaccine doses. When comparing two vs. three WT vaccine doses among SARS-CoV-2 negative participants, we did not detect a difference in BA.4/5 percent inhibition, but there was a difference in WT percent inhibition. Among those with previous SARS-CoV-2 infection(s), when comparing two vs. three WT vaccine doses, there was no observed difference between groups. These findings demonstrate that additional Whttps://www.covid19immunitytaskforce.ca/citf-databank/#accessing https://www.covid19immunitytaskforce.ca/citf-databank/#accessinguhan Hu-1 platform mRNA vaccines did not improve NtAb response to BA.4/5, but prior SARS-CoV-2 infection enhances NtAb response., Competing Interests: The author(s) declared that there are no conflicts of interest., (© 2023 The Authors.)

Aim of the Review: Improving rates of organ donation among patients with out-of-hospital cardiac arrest who do not survive is an opportunity to save countless lives. The objectives of this scientific statement were to do the following: define the opportunity for organ donation among patients with out-of-hospital cardiac arrest; identify challenges and opportunities associated with organ donation by patients with cardiac arrest; identify strategies, including a generic protocol for organ donation after cardiac arrest, to increase the rate and consistency of organ donation from this population; and provide rationale for including organ donation as a key clinical outcome for all future cardiac arrest clinical trials and registries., Methods: The scope of this International Liaison Committee on Resuscitation scientific statement was approved by the International Liaison Committee on Resuscitation board and the American Heart Association, posted on ILCOR.org for public comment, and then assigned by section to primary and secondary authors. A unique literature search was completed and updated for each section., Results: There are a number of defining pathways for patients with out-of-hospital cardiac arrest to become organ donors; however, modifications in the Maastricht classification system need to be made to correctly identify these donors and to report outcomes with consistency. Suggested modifications to the minimum data set for reporting cardiac arrests will increase reporting of organ donation as an important resuscitation outcome. There are a number of challenges with implementing uncontrolled donation after cardiac death protocols, and the greatest impediment is the lack of legislation in most countries to mandate organ donation as the default option. Extracorporeal cardiopulmonary resuscitation has the potential to increase organ donation rates, but more research is needed to derive neuroprognostication rules to guide clinical decision-making about when to stop extracorporeal cardiopulmonary resuscitation and to evaluate cost-effectiveness., Conclusions: All health systems should develop, implement, and evaluate protocols designed to optimize organ donation opportunities for patients who have an out-of-hospital cardiac arrest and failed attempts at resuscitation.

Aim of the Review: Improving rates of organ donation among patients with out-of-hospital cardiac arrest who do not survive is an opportunity to save countless lives. The objectives of this scientific statement were to do the following: define the opportunity for organ donation among patients with out-of-hospital cardiac arrest; identify challenges and opportunities associated with organ donation by patients with cardiac arrest; identify strategies, including a generic protocol for organ donation after cardiac arrest, to increase the rate and consistency of organ donation from this population; and provide rationale for including organ donation as a key clinical outcome for all future cardiac arrest clinical trials and registries., Methods: The scope of this International Liaison Committee on Resuscitation scientific statement was approved by the International Liaison Committee on Resuscitation board and the American Heart Association, posted on ILCOR.org for public comment, and then assigned by section to primary and secondary authors. A unique literature search was completed and updated for each section., Results: There are a number of defining pathways for patients with out-of-hospital cardiac arrest to become organ donors; however, modifications in the Maastricht classification system need to be made to correctly identify these donors and to report outcomes with consistency. Suggested modifications to the minimum data set for reporting cardiac arrests will increase reporting of organ donation as an important resuscitation outcome. There are a number of challenges with implementing uncontrolled donation after cardiac death protocols, and the greatest impediment is the lack of legislation in most countries to mandate organ donation as the default option. Extracorporeal cardiopulmonary resuscitation has the potential to increase organ donation rates, but more research is needed to derive neuroprognostication rules to guide clinical decision-making about when to stop extracorporeal cardiopulmonary resuscitation and to evaluate cost-effectiveness., Conclusions: All health systems should develop, implement, and evaluate protocols designed to optimise organ donation opportunities for patients who have an out-of-hospital cardiac arrest and failed attempts at resuscitation., (Copyright © 2023 European Resuscitation Council, merican Heart Association, Inc., International Liaison Committee on Resuscitation. Published by Elsevier B.V. All rights reserved.)

Background: Biosensor technologies have been proposed as a solution to provide recognition and facilitate earlier responses to unwitnessed out-of-hospital cardiac arrest (OHCA) cases. We sought to estimate the effect of recognition on survival and modelled the potential incremental impact of increased recognition of unwitnessed cases on survival to hospital discharge, to demonstrate the potential benefit of biosensor technologies., Methods: We included cases from the British Columbia Cardiac Arrest Registry (2019-2020), which includes Emergency Medical Services (EMS)-assessed OHCAs. We excluded cases that would not have benefitted from early recognition (EMS-witnessed, terminal illness, or do-not-resuscitate). Using a mediation analysis, we estimated the relative benefits on survival of a witness recognizing vs. intervening in an OHCA; and estimated the expected additional number of survivors resulting from increasing recognition alone using a bootstrap logistic regression framework., Results: Of 13,655 EMS-assessed cases, 11,412 were included (6314 EMS-treated, 5098 EMS-untreated). Survival to hospital discharge was 191/8879 (2.2%) in unwitnessed cases and 429/2533 (17%) in bystander-witnessed cases. Of the total effect attributable to a bystander witness, recognition accounted for 84% (95% CI: 72, 86) of the benefit. If all previously unwitnessed cases had been bystander witnessed, we would expect 1198 additional survivors. If these cases had been recognized, but no interventions performed, we would expect 912 additional survivors., Conclusion: Unwitnessed OHCA account for the majority of OHCAs, yet survival is dismal. Methods to improve recognition, such as with biosensor technologies, may lead to substantial improvements in overall survival., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aim: We sought to describe the characteristics of at-school out-of-hospital cardiac arrests cases, subsequent basic life support, as well as ultimate patient outcomes., Methods: This was a nation-wide, multicentre, retrospective cohort study from the French national population-based RéAC out-of-hospital cardiac arrest registry (July 2011 - March 2023). We compared the characteristics and outcomes of cases occurring at schools vs. in other public places., Results: Of the 149,088 national out-of-hospital cardiac arrests, 25,071 were public: 86 (0.3%) and 24,985 (99.7%) in schools and other public places, respectively. At-school out-of-hospital cardiac arrests, in comparison to other public places, were: significantly younger (median: 42.5 vs. 58 years, p < 0.001); more commonly of a medical cause (90.7% vs. 63.8%, p < 0.001), more commonly bystander-witnessed (93.0% vs. 73.4%, p < 0.001) and recipients of bystander cardiopulmonary resuscitation (78.8% vs. 60.6%, p = 0.001) with shorter median no-flow durations (2 min. vs. 7 min.); with greater bystander automated external defibrillator application (38.9% vs. 18.4%) and defibrillation (23.6%, vs. 7.9%; all p < 0.001). At-school patients had greater rates of return of spontaneous circulation than out-of-school ones (47.7%, vs. 31.8%; p = 0.002), higher rates of survival at arrival at hospital (60.5% vs. 30.7%; p < 0.001) and at 30-days (34.9% vs. 11.6%; p < 0.001), and survival with favourable neurological outcomes at 30 days (25.9% vs. 9.2%; p < 0.001)., Conclusion: At-school out-of-hospital cardiac arrests were rare in France, however demonstrated favourable prognostic features and outcomes. The use of automated external defibrillators in at-school cases, while more common than cases occurring elsewhere, should be improved., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: After resuscitation from out-of-hospital cardiac arrest (OHCA) by Emergency Medical Services (EMS), the amount of time that should be dedicated to pre-transport stabilization is unclear. We examined whether the time spent on-scene after return of spontaneous circulation (ROSC) was associated with patient outcomes., Methods: We examined consecutive adult EMS-treated OHCAs from the British Columbia Cardiac Arrest registry (January 1/2019-June 1/2021) that had on-scene ROSC (sustained to scene departure). The primary outcome was favourable neurological outcome (Cerebral Performance Category ≤ 2) at hospital discharge; secondary outcomes were re-arrest during transport and hospital-discharge survival. Using adjusted logistic regression models, we estimated the association between the post-resuscitation on-scene interval (divided into quartiles) and outcomes., Results: Of 1653 cases, 611 (37%) survived to hospital discharge, and 523 (32%) had favourable neurological outcomes. The median post-resuscitation on-scene interval was 18.8 minutes (IQR:13.0-25.5). Compared to the first post-resuscitation on-scene interval quartile, neither the second (adjusted odds ratio [AOR] 1.19; 95% CI 0.72-1.98), third (AOR 1.10; 95% CI 0.67-1.81), nor fourth (AOR 1.54; 95% CI 0.93-2.56) quartiles were associated with favourable neurological outcomes; however, the fourth quartile was associated with a greater odds of hospital-discharge survival (AOR 1.73; 95% CI 1.05-2.85), and both the third (AOR 0.40; 95% CI 0.22-0.72) and fourth (AOR 0.44;95% CI 0.24-0.81) quartiles were associated with a lower odds of intra-transport re-arrest., Conclusion: Among resuscitated OHCAs, increased post-resuscitation on-scene time was not associated with improved neurological outcomes, but was associated with improved survival to hospital discharge and decreased intra-transport re-arrest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objectives: The objective was to conduct a systematic review and qualitative evidence synthesis (QES) to identify best practices, benefits, harms, facilitators, and barriers to the routine collection of sociodemographic variables in emergency departments (EDs)., Methods: This work is a systematic review and QES. We conducted a comprehensive search of Medline (Ovid), CINAHL (Ebsco), Cochrane Central (OVID), EMBASE (Ovid), and the multidisciplinary Web of Science Core database using peer-reviewed search strategies, complemented by a gray literature search. We included citations containing perspectives on routine sociodemographic variable collection in EDs and recommendations on definitions or processes of collection or benefits, harms, facilitators, or barriers related to the routine collection of sociodemographic variables in EDs. We conducted this systematic review and QES adhering to the Joanna Briggs Institute guidelines. Two reviewers independently selected included studies and extracted data. We conducted a best-fit framework synthesis and paired inductive thematic analysis of the included studies. We generated recommendations based on the QES., Results: We included 21 unique reports that enrolled 10,454 patients or respondents in our systematic review and QES. Publication dates of included studies ranged from 2011 to 2021. Included citations were published in Australia, Canada, and the United States. We synthesized 11 benefits, 14 potential harms, 15 barriers, and 19 facilitators and identified 14 best practice recommendations from included citations., Conclusions: Health systems should routinely collect sociodemographic variables in EDs guided by recommendations that minimize harms and maximize benefits and consider relevant barriers and facilitators. Our recommendations can serve as a guide for the equity-focused reformation of emergency medicine health information systems., (© 2022 The Authors. Academic Emergency Medicine published by Wiley Periodicals LLC on behalf of Society for Academic Emergency Medicine.)

Background: Increasing the interval between the first and second SARS-CoV-2 vaccine doses enhances vaccine immunogenicity, however the optimal timing of the third vaccine is unknown. In this study, we investigated how the time interval between the first and second (V1-V2), or second and third (V2-V3) doses affects immunogenicity after three doses of the BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccine., Methods: This is an observational cohort consisting of 360 participants enrolled in the COVID-19 Occupational Risks, Seroprevalence, and Immunity among Paramedics in Canada (CORSIP) study. Immune responses to BA.1 and other variants were measured from serum using an ACE2 competitive binding assay for surrogate SARS-CoV-2 neutralization. We fit a multiple linear regression model to estimate the independent association between both the V1-V2 and V2-V3 intervals and serum SARS-CoV-2 neutralization, while adjusting for age, sex, and the V3-to-blood collection interval. We examined vaccine dosing intervals as continuous variables and categorized them into quartiles., Results: The mean age was 40 years, 45% were female sex (at birth), and the median BA.1 surrogate neutralization was 61% (IQR 38-77%). The multivariate analysis indicated that longer V1-V2 (β = 0.1292, 95% CI: 0.04807-0.2104) and V2-V3 (β = 0.2653, 95% CI: 0.2291-0.3015) intervals were associated with increased surrogate neutralization of BA.1. These results were consistent when examining responses against Spike from other SARS-CoV-2 strains. When categorized into V2-V3 quartiles, the first (56-231 days), and second (231-266 days) quartiles demonstrated decreased BA.1 surrogate neutralization compared to the longest V2-V3 quartile (282-329 days). There was no significant difference in surrogate neutralization between the long (266-282 days) and longest (282-329 days) V2-V3 intervals., Conclusion: Longer intervals between first, second and third doses are independently associated with increased immunogenicity for all tested SARS-CoV-2 strains. Increasing the intervals between the second and third vaccine doses up to 8.9 months provided additive benefits increasing the immunogenicity of BNT162b2 vaccine schedules., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Brian Grunau reports financial support was provided by Government of Canada. Brian Grunau reports financial support was provided by Michael Smith Foundation for Health Research. Mohammad E. Karim reports financial support was provided by Michael Smith Foundation for Health Research. Michael Asamoah-Boaheng reports financial support was provided by Michael Smith Foundation for Health Research. Martin Prusinkiewicz reports financial support was provided by Canadian Institutes of Health Research., (© 2023 The Authors.)

Objective: We investigated sex differences in 1-year survival in a cohort of patients who survived out-of-hospital cardiac arrest (OHCA) to hospital discharge. We hypothesized that female sex is associated with higher 1-year posthospital discharge survival., Methods: A retrospective analysis of linked data (2011-2017) from clinical databases in British Columbia (BC) was conducted. We used Kaplan-Meier curves, stratified by sex, to display survival up to 1-year, and the log-rank test to test for significant sex differences. This was followed by multivariable Cox proportional hazards analysis to investigate the association between sex and 1-year mortality. The multivariable analysis adjusted for variables known to be associated with survival, including variables related to OHCA characteristics, comorbidities, medical diagnoses, and in-hospital interventions., Results: We included 1278 hospital-discharge survivors; 284 (22.2%) were female. Females had a lower proportion of OHCA occurring in public locations (25.7% vs. 44.0%, P  < 0.001), a lower proportion with a shockable rhythm (57.7% vs. 77.4%, P  < 0.001), and fewer hospital-based acute coronary diagnoses and interventions. One-year survival for females and males was 90.5% and 92.4%, respectively (log-rank P  = 0.31). Unadjusted (hazard ratio [HR] males vs. females 0.80, 95% confidence interval [CI] 0.51-1.24, P  = 0.31) and adjusted (HR males vs. females 1.14, 95% CI 0.72-1.81, P  = 0.57) models did not detect differences in 1-year survival by sex., Conclusion: Females have relatively unfavorable prehospital characteristics in OHCA and fewer hospital-based acute coronary diagnoses and interventions. However, among survivors to hospital discharge, we found no significant difference between males and females in 1-year survival, even after adjustment., (© 2023 The Authors. JACEP Open published by Wiley Periodicals LLC on behalf of American College of Emergency Physicians.)

Background: Refractory out-of-hospital cardiac arrest (OHCA) treated with standard advanced cardiac life support (ACLS) has poor outcomes. Transport to hospital followed by in-hospital extracorporeal cardiopulmonary resuscitation (ECPR) initiation may improve outcomes. We performed a pooled individual patient data analysis of two randomised controlled trials evaluating ECPR based approach in OHCA., Methods: The individual patient data from two published randomised controlled trials (RCTs) were pooled: ARREST (enrolled Aug 2019-June 2020; NCT03880565) and PRAGUE-OHCA (enrolled March 1, 2013-Oct 25, 2020; NCT01511666). Both trials enrolled patients with refractory OHCA and compared: intra-arrest transport with in-hospital ECPR initiation (invasive approach) versus continued standard ACLS. The primary outcome was 180-day survival with favourable neurological outcome (defined as Cerebral Performance Category 1-2). Secondary outcomes included: cumulative survival at 180 days, 30-day favourable neurological survival, and 30-day cardiac recovery. Risk of bias in each trial was assessed by two independent reviewers using the Cochrane risk-of-bias tool. Heterogeneity was assessed via Forest plots., Findings: The two RCTs included 286 patients. Of those randomised to the invasive (n = 147) and standard (n = 139) groups, respectively: the median age was 57 (IQR 47-65) and 58 years (IQR 48-66), and the median duration of resuscitation was 58 (IQR 43-69) and 49 (IQR 33-71) minutes (p = 0.17). In a modified intention to treat analysis, 45 (32.4%) in the invasive and 29 (19.7%) patients in the standard arm survived to 180 days with a favourable neurological outcome [absolute difference (AD), 95% CI: 12.7%, 2.6-22.7%, p = 0.015]. Forty-seven (33.8%) and 33 (22.4%) patients survived to 180 days [HR 0.59 (0.43-0.81); log rank test p = 0.0009]. At 30 days, 44 (31.7%) and 24 (16.3%) patients had favourable neurological outcome (AD 15.4%, 5.6-25.1%, p = 0.003), 60 (43.2%), and 46 (31.3%) patients had cardiac recovery (AD: 11.9%, 0.7-23%, p = 0.05), in the invasive and standard arms, respectively. The effect was larger in patients presenting with shockable rhythms (AD 18.8%, 7.6-29.4; p = 0.01; HR 2.26 [1.23-4.15]; p = 0.009) and prolonged CPR (>45 min; HR 3.99 (1.54-10.35); p = 0.005)., Interpretation: In patients with refractory OHCA, the invasive approach significantly improved 30- and 180-day neurologically favourable survival., Funding: None., Competing Interests: Jan Belohlavek has received research grant from the Internal Grant Agency Ministry of Health, Czech Republic (NT 13225-4/2012) for the PRAGUE OHCA study and is supported by Charles University Research program “Cooperatio – Intensive Care Medicine” and by a research grant from the Ministry of Health, Czech Republic – conceptual development of research organisation, General University Hospital in Prague, MH CZ-DRO-VFN64165. JB also served as a consultant to Abiomed, Getinge, Xenios, and Resuscitec companies. Demetris Yannopoulos has no financial conflicts of interest. Has received NIH funding for the ARREST trial and research in the field of resuscitation. Further has received a grants from Helmsley Charitable Foundation to implement ECPR in the state of MN and deliver 8500 AEDs to first responders. Jason Bartos has no financial conflicts of interest. Has received NIH funding for research in the field of resuscitation. Has received grant funding from the Helmsley Charitable Foundation to implement ECPR in the state of MN and a second grant to distribute AEDs to first responders. Has unpaid positions on the American Heart Association Emergency Care Committee, Science Subcommittee. Served as the President of the Minnesota Mobile Resuscitation Consortium. Fabio Silvio Taccone is a scientific advisor for EUROSETS. Tom P. Aufderheide has no financial conflicts of interest. Has received NIH funding for the ARREST trial and research in the field of resuscitation. He is a consultant for Medtronic, Inc., and has ongoing clinical trials with Cytovale, Inflammatix, Inc., Abbott Laboratories, and ZOLL Medical Corp. All other authors declare no competing interests., (© 2023 The Authors.)

Aims: The time-dependent prognostic role of bystander cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) patients has not been described with great precision, especially for neurologic outcomes. Our objective was to assess the association between bystander CPR, emergency medical service (EMS) response time, and OHCA patients' outcomes., Methods: This cohort study used the Resuscitation Outcomes Consortium Cardiac Epidemiologic Registries. Bystander-witnessed adult OHCA treated by EMS were included. The primary outcome was survival to hospital discharge and secondary outcome was survival with a good neurologic outcome (modified Rankin scale 0-2). Multivariable logistic regression models were used to assess the associations and interactions between bystander CPR, EMS response time and clinical outcomes., Results: Out of 229,637 patients, 41,012 were included (18,867 [46.0%] without bystander CPR and 22,145 [54.0%] with bystander CPR). Bystander CPR was independently associated with higher survival (adjusted odds ratio [AOR] = 1.70 [95%CI 1.61-1.80]) and survival with a good neurologic outcome (AOR = 1.87 [95%CI 1.70-2.06]), while longer EMS response times were independently associated with lower survival to hospital discharge (each additional minute of EMS response time: AOR = 0.92 [95%CI 0.91-0.93], p < 0.001) and lower survival with a good neurologic outcome (AOR = 0.88 [95%CI 0.86-0.89], p < 0.001). There was no interaction between bystander CPR and EMS response time's association with survival (p = 0.12) and neurologic outcomes (p = 0.65)., Conclusions: Although bystander CPR is associated with an immediate increase in odds of survival and of good neurologic outcome for OHCA patients, it does not influence the negative association between longer EMS response time and survival and good neurologic outcome., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Sudden cardiac arrest (SCA) is a leading cause of mortality worldwide. The SCA-to-resuscitation interval is a key determinant of patient outcomes, highlighting the clinical need for reliable and timely detection of SCA. Near-infrared spectroscopy (NIRS), a non-invasive optical technique, may have utility for this application. We investigated transcutaneous NIRS as a method to detect pentobarbital-induced changes during cardiac arrest in eight Yucatan miniature pigs. NIRS measurements during cardiac arrest were compared to invasively acquired carotid blood pressure and partial oxygen pressure (PO 2 ) of spinal cord tissues. We observed statistically significant decreases in mean arterial pressure (MAP) 64.68 mmHg ± 13.08, p < 0.0001), spinal cord PO 2 (38.16 mmHg ± 20.04, p = 0.0028), and NIRS-derived tissue oxygen saturation (TSI%) (14.50% ± 3.80, p < 0.0001) from baseline to 5 min after pentobarbital administration. Euthanasia-to-first change in hemodynamics for MAP and TSI (%) were similar [MAP (10.43 ± 4.73 s) vs TSI (%) (12.04 ± 1.85 s), p = 0.3714]. No significant difference was detected between NIRS and blood pressure-derived pulse rates during baseline periods (p > 0.99) and following pentobarbital administration (p = 0.97). Transcutaneous NIRS demonstrated the potential to identify rapid hemodynamic changes due to cardiac arrest in periods similar to invasive indices. We conclude that transcutaneous NIRS monitoring may present a novel, non-invasive approach for SCA detection, which warrants further investigation., (© 2023. The Author(s).)

Background: Approximately one-quarter of emergency department (ED) visits for alcohol withdrawal result in unscheduled 1-week ED return visits, but it is unclear what patient and clinical factors may impact this outcome METHODS: From January 1, 2015, to December 31, 2018, at three urban EDs in Vancouver, Canada, we studied patients who were discharged with a primary or secondary diagnosis of alcohol withdrawal. We performed a structured chart review to ascertain patient characteristics, ED treatments, and the outcome of an ED return within 1 week of discharge. We used univariable and multivariable Bayesian binomial regression to identify characteristics associated with being in the upper quartile of 1-week ED revisits., Results: We collected 935 ED visits among 593 unique patients. Median age was 45 years (interquartile range 34 to 55 years) and 71% were male. The risk of a 1-week ED revisit was 15.0% (IQR 12.3; 19.5%). After adjustment, factors independently associated with a high risk for return included any prior ED visit within 30 days, no fixed address, initial blood alcohol level > 45 mmol/L, and initial Clinical Institute Withdrawal Assessment-alcohol revised score > 23. These factors explained 41% of the overall variance in revisits., Conclusion: Among discharged ED patients with alcohol withdrawal, we describe high-risk patient characteristics associated with 1-week ED revisits, and these findings may assist clinicians to facilitate appropriate discharge planning with access to integrated follow-up support., (© 2023. The Author(s), under exclusive licence to Canadian Association of Emergency Physicians (CAEP)/ Association Canadienne de Médecine d'Urgence (ACMU).)

The relationship between antibodies to wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens and the risk of breakthrough infections is unclear, especially during circulation of the Omicron strain. We investigated the association of anti-spike and anti-receptor binding domain antibody levels and the risk of subsequent breakthrough coronavirus disease 2019 (COVID-19). We included adult paramedics from an observational cohort study who received 2 mRNA vaccines but did not have COVID-19 before the blood collection. Higher postvaccination antibody levels to wild-type SARS-CoV-2 antigens were associated with a reduced risk of COVID-19. Further research into clinical utility of antibody levels, to inform a threshold for protection and timing of boosters, should be prioritized., (The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Emerging evidence indicates that longer SARS-CoV-2 vaccine dosing intervals results in an enhanced immune response. However, the optimal vaccine dosing interval for achieving maximum immunogenicity is unclear., Methods: This study included samples from adult paramedics in Canada who received two doses of either BNT162b2 or mRNA-1273 vaccines and provided blood samples six months (170 to 190 days) after the first vaccine dose. The main exposure variable was vaccine dosing interval (days), categorized as "short" (first quartile), "moderate" (second quartile), "long" (third quartile), and "longest " interval (fourth quartile). The primary outcome was total spike antibody concentrations, measured using the Elecsys SARS-CoV-2 total antibody assay. Secondary outcomes included spike and receptor-binding domain (RBD) immunoglobulin G (IgG) antibody concentrations, and inhibition of angiotensin-converting enzyme 2 (ACE-2) binding to wild-type spike protein and several different Delta variant spike proteins. We fit a multiple log-linear regression model to investigate the association between vaccine dosing intervals and the antibody concentrations., Results: A total of 564 adult paramedics (mean age 40 years, SD=10) were included. Compared to "short interval" (≤30 days), vaccine dosing intervals of the long (39-73 days) group (β= 0.31, 95% Confidence interval (CI): 0.10-0.52) and the longest (≥74 days) group (β = 0.82. 95% CI: 0.36-1.28) were associated with increased spike total antibody concentration. Compared to the short interval, the longest interval quartile was associated with higher spike IgG antibodies, while the long and longest intervals were associated with higher RBD IgG antibody concentrations. Similarly, the longest dosing intervals increased inhibition of ACE-2 binding to viral spike protein., Conclusion: Increased mRNA vaccine dosing intervals longer than 38 days result in higher levels of anti-spike antibodies and ACE-2 inhibition when assessed six months after the first COVID-19 vaccine., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Asamoah-Boaheng et al.)

Aim: Longer emergency medical system cardiopulmonary-resuscitation-to-return of-spontaneous-circulation (EMS CPR-to-ROSC) interval has been associated with worse hospital discharge outcomes after out-of-hospital cardiac arrest (OHCA). We hypothesized that this association extends post-discharge in hospital survivors. We investigated whether pre-arrest co-morbidities influence the duration of resuscitation., Methods: We included EMS-treated adult OHCA (January 2009 - December 2016) from British Columbia Cardiac Arrest Registry linked to provincial databases. Pre-OHCA characteristics were compared by ≤10, 10-20, and >20 min interval categories. Outcomes included survival and functional outcomes at hospital discharge and 1- and 3-year survival. We examined the relationship between CPR-to-ROSC intervals and survival using Kaplan-Meier. We examined the relationship between the CPR-to-ROSC interval (continuous variable) with all outcomes using regression models., Results: Among 10,241 OHCA, 4604 (45%) achieved ROSC, with a median CPR-to-ROSC interval of 15.5 (IQR 9.0-22.9) minutes. Diabetes, chronic kidney disease, and prior myocardial infarction were associated with longer CPR-to-ROSC intervals. 1245 (12.2%) survived to hospital discharge. Among hospital survivors, Kaplan-Meier survival at 1- and 3-years were 92% [95% CI 90-93%] and 84% [95% CI 82-86%] respectively; survival curves stratified by CPR-to-ROSC intervals were not statistically different. Longer CPR-to-ROSC interval was non-linearly associated with lower survival and functional outcomes at hospital discharge but not with post-discharge outcomes., Conclusion: Longer CPR-to-ROSC interval was associated with lower survival at hospital discharge and was influenced by pre-arrest co-morbidities. However, these intervals were not associated with long-term survival or functional outcome among hospital survivors, suggesting early risk of longer CPR-to-ROSC intervals does not persist., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Emergency dispatch centres receive emergency calls and assign resources. Out-of-hospital cardiac arrests (OHCA) can be classified as appropriate (requiring emergent response) or inappropriate (requiring non-emergent response) for resuscitation. We sought to determine system accuracy in emergency medical services (EMS) OHCA response allocation., Methods: We analyzed EMS-assessed non-traumatic OHCA records from the British Columbia (BC) Cardiac Arrest registry (January 1, 2019-June 1, 2021), excluding EMS-witnessed cases. In BC the "Medical Priority Dispatch System" is used. We classified EMS dispatch as "emergent" or "non-emergent" and compared to the gold standard of whether EMS personnel decided treatment was appropriate upon scene arrival. We calculated sensitivity, specificity, and positive and negative predictive values (PPV, NPV), with 95% CI's., Results: Of 15,371 non-traumatic OHCAs, the median age was 65 (inter quartile range 51-78), and 4834 (31%) were women; 7152 (47%) were EMS-treated, of whom 651 (9.1%) survived). Among EMS-treated cases 6923/7152 had an emergent response (sensitivity = 97%, 95% CI 96-97) and among EMS-untreated cases 3951/8219 had a non-emergent response (specificity = 48%, 95% CI, 47 to 49). Among cases with emergent dispatch, 6923/11191 were EMS-treated (PPV = 62%, 95% CI 61-62), and among those with non-emergent dispatch, 3951/4180 were EMS-untreated (NPV = 95%, 95% CI 94-95); 229/4180 (5.5%) with a non-emergent dispatch were treated by EMS., Conclusion: The dispatch system in BC has a high sensitivity and moderate specificity in sending the appropriate responses for OHCAs deemed appropriate for treatment by paramedics. Future research may address strategies to increase system specificity, and decrease the incidence of non-emergent dispatch to EMS-treated cases., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Aim: To compare walking access times to automated external defibrillators (AEDs) between area-level quintiles of socioeconomic status (SES) in out-of-hospital cardiac arrest (OHCA) cases occurring in 2 major urban regions of Canada and France., Methods: This was an international, multicenter, retrospective cohort study of adult, non-traumatic OHCA cases in the metropolitan Vancouver (Canada) and Rhône County (France) regions that occurred between 2014 and 2018. We calculated area-level SES for each case, using quintiles of country-specific scores (Q5 = most deprived). We identified AED locations from local registries. The primary outcome was the simulated walking time from the OHCA location to the closest AED (continuous and dichotomized by a 3-minute 1-way threshold). We fit multivariate models to analyze the association between OHCA-to-AED walking time and outcomes (Q5 vs others)., Results: A total of 6,187 and 3,239 cases were included from the Metro Vancouver and Rhône County areas, respectively. In Metro Vancouver Q5 areas (vs Q1-Q4), areas, AEDs were farther from (79 % over 400 m from case vs 67 %, p < 0.001) and required longer walking times to (97 % above 3 min vs 91 %, p < 0.001) cases. In Rhône Q5 areas, AEDs were closer than in other areas (43 % over 400 m from case vs 50 %, p = 0.01), yet similarly poorly accessible (85 % above 3 min vs 86 %, p = 0.79). In multivariate models, AED access time ≥ 3 min was associated with decreased odds of survival at hospital discharge in Metro Vancouver (odds ratio 0.41, 95 % CI [0.23-0.74], p = 0.003)., Conclusions: Accessibility of public AEDs was globally poor in Metro Vancouver and Rhône, and even poorer in Metro Vancouver's socioeconomically deprived areas., (Copyright © 2022 Elsevier B.V. All rights reserved.)