Impact of Bystander Automated External Defibrillator Use on Survival and Functional Outcomes in Shockable Observed Public Cardiac Arrests.

BACKGROUND: Survival following out-of-hospital cardiac arrest (OHCA) with shockable rhythms can be improved with early defibrillation. Although shockable OHCA accounts for only ≈25% of overall arrests, ≈60% of public OHCAs are shockable, offering the possibility of restoring thousands of individuals to full recovery with early defibrillation by bystanders. We sought to determine the association of bystander automated external defibrillator use with survival and functional outcomes in shockable observed public OHCA. METHODS: From 2011 to 2015, the Resuscitation Outcomes Consortium prospectively collected detailed information on all cardiac arrests at 9 regional centers. The exposures were shock administration by a bystander-applied automated external defibrillator in comparison with initial defibrillation by emergency medical services. The primary outcome measure was discharge with normal or near-normal (favorable) functional status defined as a modified Rankin Score ≤2. Survival to hospital discharge was the secondary outcome measure. RESULTS: Among 49 555 OHCAs, 4115 (8.3%) observed public OHCAs were analyzed, of which 2500 (60.8%) were shockable. A bystander shock was applied in 18.8% of the shockable arrests. Patients shocked by a bystander were significantly more likely to survive to discharge (66.5% versus 43.0%) and be discharged with favorable functional outcome (57.1% versus 32.7%) than patients initially shocked by emergency medical services. After adjusting for known predictors of outcome, the odds ratio associated with a bystander shock was 2.62 (95% confidence interval, 2.07-3.31) for survival to hospital discharge and 2.73 (95% confidence interval, 2.17-3.44) for discharge with favorable functional outcome. The benefit of bystander shock increased progressively as emergency medical services response time became longer. CONCLUSIONS: Bystander automated external defibrillator use before emergency medical services arrival in shockable observed public OHCA was associated with better survival and functional outcomes. Continued emphasis on public automated external defibrillator utilization programs may further improve outcomes of OHCA.

Optimizing a Drone Network to Deliver Automated External Defibrillators.

BACKGROUND: Public access defibrillation programs can improve survival after out-of-hospital cardiac arrest, but automated external defibrillators (AEDs) are rarely available for bystander use at the scene. Drones are an emerging technology that can deliver an AED to the scene of an out-of-hospital cardiac arrest for bystander use. We hypothesize that a drone network designed with the aid of a mathematical model combining both optimization and queuing can reduce the time to AED arrival. METHODS: We applied our model to 53 702 out-of-hospital cardiac arrests that occurred in the 8 regions of the Toronto Regional RescuNET between January 1, 2006, and December 31, 2014. Our primary analysis quantified the drone network size required to deliver an AED 1, 2, or 3 minutes faster than historical median 911 response times for each region independently. A secondary analysis quantified the reduction in drone resources required if RescuNET was treated as a large coordinated region. RESULTS: The region-specific analysis determined that 81 bases and 100 drones would be required to deliver an AED ahead of median 911 response times by 3 minutes. In the most urban region, the 90th percentile of the AED arrival time was reduced by 6 minutes and 43 seconds relative to historical 911 response times in the region. In the most rural region, the 90th percentile was reduced by 10 minutes and 34 seconds. A single coordinated drone network across all regions required 39.5% fewer bases and 30.0% fewer drones to achieve similar AED delivery times. CONCLUSIONS: An optimized drone network designed with the aid of a novel mathematical model can substantially reduce the AED delivery time to an out-of-hospital cardiac arrest event.

Out-of-hospital cardiac arrest in high-rise buildings: delays to patient care and effect on survival.

BACKGROUND: The increasing number of people living in high-rise buildings presents unique challenges to care and may cause delays for 911-initiated first responders (including paramedics and fire department personnel) responding to calls for out-of-hospital cardiac arrest. We examined the relation between floor of patient contact and survival after cardiac arrest in residential buildings. METHODS: We conducted a retrospective observational study using data from the Toronto Regional RescuNet Epistry database for the period January 2007 to December 2012. We included all adult patients (≥ 18 yr) with out-of-hospital cardiac arrest of no obvious cause who were treated in private residences. We excluded cardiac arrests witnessed by 911-initiated first responders and those with an obvious cause. We used multivariable logistic regression to determine the effect on survival of the floor of patient contact, with adjustment for standard Utstein variables. RESULTS: During the study period, 7842 cases of out-of-hospital cardiac arrest met the inclusion criteria, of which 5998 (76.5%) occurred below the third floor and 1844 (23.5%) occurred on the third floor or higher. Survival was greater on the lower floors (4.2% v. 2.6%, p = 0.002). Lower adjusted survival to hospital discharge was independently associated with higher floor of patient contact, older age, male sex and longer 911 response time. In an analysis by floor, survival was 0.9% above floor 16 (i.e., below the 1% threshold for futility), and there were no survivors above the 25th floor. INTERPRETATION: In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.

A Novel Approach to Improve Time to First Shock in Prehospital STEMI Complicated by Ventricular Fibrillation.

Lethal cardiac arrhythmias such as ventricular fibrillation and pulseless ventricular tachycardia (VF/pVT) complicate up to 6% of all out-of-hospital STEMIs. Typically, paramedics respond to this by applying defibrillation pads and delivering a shock as soon as possible. A recently introduced "pads-on" protocol directed paramedics to apply defibrillation pads to all STEMI patients (regardless of clinical stability) with the aim of decreasing time to first shock. In this article we present two cases of prehospital STEMI complicated by VF to illustrate times to first shock for the two different protocols. One case each of a STEMI complicated by VF before implementation of the pads-on protocol and after the implementation of the protocol is presented. An important difference in the time to first shock is noted between the two patients with STEMI complicated by VF. While it took 2 min 43 s for the pads-off patient to be defibrillated, only 27 s elapsed before the pads-on patient was defibrillated. These two cases demonstrate that the application of defibrillation pads immediately following the diagnosis of prehospital STEMI has the potential to decrease the time to shock in patients suffering VF/pVT.

Impact of the COVID-19 pandemic on Canadian emergency medical system management of out-of-hospital cardiac arrest: A retrospective cohort study.

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.

Prediction models in prehospital and emergency medicine research: How to derive and internally validate a clinical prediction model.

Clinical prediction models are created to help clinicians with medical decision making, aid in risk stratification, and improve diagnosis and/or prognosis. With growing availability of both prehospital and in-hospital observational registries and electronic health records, there is an opportunity to develop, validate, and incorporate prediction models into clinical practice. However, many prediction models have high risk of bias due to poor methodology. Given that there are no methodological standards aimed at developing prediction models specifically in the prehospital setting, the objective of this paper is to describe the appropriate methodology for the derivation and validation of clinical prediction models in this setting. What follows can also be applied to the emergency medicine (EM) setting. There are eight steps that should be followed when developing and internally validating a prediction model: (1) problem definition, (2) coding of predictors, (3) addressing missing data, (4) ensuring adequate sample size, (5) variable selection, (6) evaluating model performance, (7) internal validation, and (8) model presentation. Subsequent steps include external validation, assessment of impact, and cost-effectiveness. By following these steps, researchers can develop a prediction model with the methodological rigor and quality required for prehospital and EM research.

Caring for the invisible and forgotten: a qualitative document analysis and experience-based co-design project to improve the care of families experiencing out-of-hospital cardiac arrest.

OBJECTIVES: The objectives of this project were to collect and analyze clinical governance documents related to family-centred care and cardiac arrest care in Canadian EMS organizations; and to improve the family-centredness of out-of-hospital cardiac arrest care through experience-based co-design. METHODS: We conducted qualitative document analysis of Canadian EMS clinical governance documents related to family-centred and cardiac arrest care, combining elements of content and thematic analysis methods. We then used experience-based co-design to develop a family-centred out-of-hospital cardiac arrest care policy and procedure template. RESULTS: Thirty-five Canadian EMS organizations responded to our requests, representing service area coverage for 80% of the Canadian population. Twenty documents were obtained for review and six overarching themes were identified: addressing family in event of in-home death, importance of family, family member escort, provider discretion and family presence discouraged. Informed by our qualitative analysis we then co-designed a policy and procedure template was created that prioritizes patient care while promotes family-centredness. CONCLUSIONS: There were few directives to support family-centred care by Canadian EMS organizations. A family-centred out-of-hospital cardiac arrest care policy and procedure template was developed using experience-based co-design to assist EMS organizations improve the family-centredness of out-of-hospital cardiac arrest care.

RéSUMé: OBJECTIFS: Les objectifs de ce projet étaient de recueillir et d'analyser des documents de gouvernance clinique liés aux soins centrés sur la famille et aux soins de l'arrêt cardiaque dans les organisations canadiennes de SMU; et d'améliorer le caractère centré sur la famille des soins en cas d'arrêt cardiaque à l'extérieur de l'hôpital grâce à une co-conception fondée sur l'expérience. MéTHODES: Nous avons effectué une analyse qualitative des documents de gouvernance clinique des SMU canadiens liés aux soins axés sur la famille et aux arrêts cardiaques, en combinant des éléments de contenu et des méthodes d'analyse thématique. Nous avons ensuite utilisé la co-conception fondée sur l'expérience pour élaborer un modèle de politique et de procédure de soins en cas d'arrêt cardiaque centrés sur la famille en dehors de l'hôpital. RéSULTATS: Trente-cinq organisations Canadiennes de SMU ont répondu à nos demandes, ce qui représente une couverture de zone de service pour 80 % de la population canadienne. Vingt documents ont été obtenus aux fins d'examen et six thèmes principaux ont été cernés: s'adresser à la famille en cas de décès à domicile, l'importance de la famille, accompagnement d'un membre de la famille, la discrétion du fournisseur et la présence de la famille découragée. Éclairés par notre analyse qualitative, nous avons ensuite co-conçu un modèle de politique et de procédure qui priorise les soins aux patients tout en favorisant l'orientation familial. CONCLUSIONS: Il y avait peu de directives pour soutenir les soins axés sur la famille par les organisations canadiennes de SMU. Un modèle de politique de soins d'arrêt cardiaque centré sur la famille a été élaboré à l'aide d'une co-conception basée sur l'expérience pour aider les organisations de SMU à améliorer l'orientation familiale des soins en cas d'arrêt cardiaque hors hôpital.

Patient safety in emergency medical services: a systematic review of the literature.

BACKGROUND: Preventable harm from medical care has been extensively documented in the inpatient setting. Emergency medical services (EMS) providers care for patients in dynamic and challenging environments; prehospital emergency care is a field that represents an area of high risk for errors and harm, but has received relatively little attention in the patient safety literature. OBJECTIVE: To identify the threats to patient safety unique to the EMS environment and interventions that mitigate those threats, we completed a systematic review of the literature. METHODS: We searched MEDLINE, EMBASE, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for combinations of key EMS and patient safety terms composed by a pan-canadian expert panel using a year limit of 1999 to 2011. We excluded commentaries, opinions, letters, abstracts, and non-english publications. Two investigators performed an independent hierarchical screening of titles, abstracts, and full-text articles blinded to source. We used the kappa statistic to examine interrater agreement. Any differences were resolved by consensus. RESULTS: We retrieved 5,959 titles, and 88 publications met the inclusion criteria and were categorized into seven themes: adverse events and medication errors (22 articles), clinical judgment (13), communication (6), ground vehicle safety (9), aircraft safety (6), interfacility transport (16), and intubation (16). Two articles were randomized controlled trials; the remainder were systematic reviews, prospective observational studies, retrospective database/chart reviews, qualitative interviews, or surveys. The kappa statistics for titles, abstracts, and full-text articles were 0.65, 0.79, and 0.87, respectively, for the first search and 0.60, 0.74, and 0.85 for the second. CONCLUSIONS: We found a paucity of scientific literature exploring patient safety in EMS. Research is needed to improve our understanding of problem magnitude and threats to patient safety and to guide interventions.

Changes in presentation, presenting severity and disposition among patients accessing emergency services during the first months of the COVID-19 pandemic in Calgary, Alberta: a descriptive study.

BACKGROUND: The COVID-19 pandemic has resulted in unique pressures on the emergency services system. This study describes changes in the presentation, presenting severity and disposition of patients accessing emergency services in Calgary, Alberta, during the first wave of the pandemic. METHODS: In this descriptive study, we constructed a population cohort of all patients who accessed emergency services by calling emergency medical services (EMS) (ambulance service that provides prehospital treatment and transport to medical facilities) or presenting directly to an emergency department (4 adult and 1 pediatric) or 2 urgent care centres in Calgary during the exposure period (December 2019 to June 2020) compared to 2 historical control periods (December to June, 2017-2018 and 2018-2019) combined. Outcomes included frequency of presentation, system flow indicators, patient severity, disposition and mortality. We used a locally estimated scatterplot smoothing function to visualize trends. We described differences at the maximum and minimum point of the exposure period compared to the control period. RESULTS: A total of 1 127 014 patient encounters were included. Compared to the control period, there was a 61% increase in the number of patients accessing EMS and a 35% decrease in the number of those presenting to an adult emergency department or urgent care centre in the COVID-19 period. The proportion of EMS calls for the highest-priority patients remained stable, whereas the proportion of patients presenting to an emergency department or urgent care centre with the highest-priority triage classification increased transiently by 0.9 percentage points (increase of 89%). A smaller proportion of patients were transported by EMS (decrease of 21%), and a greater proportion of emergency department patients were admitted to hospital (increase of 25%). After the first case was reported, the mortality rate among EMS patients increased by 265% (3.4 v. 12.4 per 1000 patient encounters). INTERPRETATION: The first wave of the COVID-19 pandemic was associated with substantial changes in the frequency and disposition of patients accessing emergency services. Further research examining the mechanism of these observations is important for mitigating the impact of future pandemics.

Clinical considerations for out-of-hospital cardiac arrest management during COVID-19.

Managing out-of-hospital cardiac arrest requires paramedics to perform multiple aerosol generating medical procedures in an uncontrolled setting. This increases the risk of cross infection during the COVID-19 pandemic. Modifications to conventional protocols are required to balance paramedic safety with optimal patient care and potential stresses on the capacity of critical care resources. Despite this, little specific advice has been published to guide paramedic practice. In this commentary, we highlight challenges and controversies regarding critical decision making around initiation of resuscitation, airway management, mechanical chest compression, and termination of resuscitation. We also discuss suggested triggers for implementation and revocation of recommended protocol changes and present an accompanying paramedic-specific algorithm.

High risk neighbourhoods: The effect of neighbourhood level factors on cardiac arrest incidence.

BACKGROUND: Numerous studies have shown significant neighbourhood level variation in out-of-hospital cardiac arrest (OHCA) incidence rates, however, few have provided an explanation for these disparities beyond traditional socioeconomic measures. METHODS: This was a retrospective study using data from a large population-based OHCA database (Rescu Epistry). We included adults ≥20 years who experienced a non-traumatic OHCA and were treated by emergency medical services within Toronto, Canada between 2006-2012. The residential address of each OHCA patient was spatially mapped to 1 of 517 Toronto census tracts (CTs). Patient and CT level characteristics were included in multivariate regression models to assess their association with OHCA incidence per 100,000 persons. RESULTS: Of the 7775 OHCAs occurring in the study area, 7692 (98.9%) were eligible for inclusion. OHCA incidence rates varied widely across CT quintiles, with rates differing almost 4-fold (109.1 per 100,000 yearly Q5 most deprived vs. 30.0 per 100,000 yearly Q1 least deprived p < 0.0001). Numerous areas of high incidence adjacent to areas of low incidence were observed. After adjustment, all variables except the Activity Friendly Index showed highly significant linear trends, with increasing age, sex ratio, diabetes prevalence, material deprivation and ethnic concentration being independently associated with increasing OHCA incidence. In contrast, we did not observe a linear relationship between high OHCA incidence and median household income. CONCLUSIONS: This study showed almost 4-fold OHCA incidence variability across a large metropolitan area. This variability was partially correlated with population and health data, but not typical socioeconomic predictors, such as median household income.

The impact of increased chest compression fraction on survival for out-of-hospital cardiac arrest patients with a non-shockable initial rhythm.

OBJECTIVE: We evaluated the effect of chest compression fraction (CCF) on survival to hospital discharge and return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA) patients with non-shockable rhythms. METHODS: This is a retrospective analysis (completed in 2016) of a prospective cohort study which included OHCA patients from ten U.S. and Canadian sites (Resuscitation Outcomes Consortium Epistry and PRIMED study (2007-2011)). We included all OHCA victims of presumed cardiac aetiology, not witnessed by emergency medical services (EMS), without automated external defibrillator shock prior to EMS arrival, receiving > 1 min of CPR with CPR process measures available, and initial non-shockable rhythm. We measured CCF using the first 5 min of electronic CPR records. RESULTS: Demographics of 12,928 adult patients were: mean age 68; male 59.9%; public location 8.5%; bystander witnessed 35.2%; bystander CPR 39.3%; median interval from 911 to defibrillator turned on 10 min:04 s; initial rhythm asystole 64.8%, PEA 26.0%, other non-shockable 9.2%; compression rate 80-120/min (69.1%); median CCF 74%; ROSC 25.6%; survival to hospital discharge 2.4%. Adjusted odds ratio (OR); 95% confidence intervals (95%CI) of survival for each CCF category were: 0-40% (2.00; 1.16, 3.32); 41-60% (0.83; 0.54, 1.24); 61-80% (1.02; 0.77, 1.35); and 81-100% (reference group). Adjusted (OR; 95%CI) of ROSC for each CCF category were: 0-40% (1.02; 0.79, 1.30); 41-60% (0.83; 0.72, 0.95); 61-80% (0.85; 0.77, 0.94); and 81-100% (reference group). CONCLUSIONS: We observed an incremental benefit from higher CCF on the incidence of ROSC, but not survival, among non-shockable OHCA patients with CCF higher than 40%.

Paediatric targeted temperature management post cardiac arrest: A systematic review and meta-analysis.

INTRODUCTION: The International Liaison Committee on Resuscitation prioritized the need to update the review on the use of targeted temperature management (TTM) in paediatric post cardiac arrest care. In this meta-analysis, the effectiveness of TTM at 32-36 °C was compared with no target or a different target for comatose children who achieve a return of sustained circulation after cardiac arrest. METHODS: Electronic databases were searched from inception to December 13, 2018. Randomized controlled trials and non-randomized studies with a comparator group that evaluated TTM in children were included. Pairs of independent reviewers extracted the demographic and outcome data, appraised risk of bias, and assessed GRADE certainty of effects. A random effects meta-analysis was undertaken where possible. RESULTS: Twelve studies involving 2060 patients were included. Two randomized controlled trials provided the evidence that TTM at 32-34 °C compared with a target at 36-37.5 °C did not statistically improve long-term good neurobehavioural survival (risk ratio: 1.15; 95% CI: 0.69-1.93), long-term survival (RR: 1.14; 95% CI: 0.93-1.39), or short-term survival (risk ratio: 1.14; 95% CI: 0.96-1.36). TTM at 32-34 °C did not show statistically increased risks of infection, recurrent cardiac arrest, serious bleeding, or arrhythmias. A novel analysis suggests that another small RCT might provide enough evidence to show benefit for TTM in out-of-hospital cardiac arrest. CONCLUSION: There is currently inconclusive evidence to either support or refute the use of TTM at 32-34 °C for comatose children who achieve return of sustained circulation after cardiac arrest. Future trials should focus on children with out-of-hospital cardiac arrest.

Improving Temporal Trends in Survival and Neurological Outcomes After Out-of-Hospital Cardiac Arrest.

BACKGROUND: Considerable effort has gone into improving outcomes from out-of-hospital cardiac arrest (OHCA). Studies suggest that survival is improving; however, prior studies had insufficient data to pursue the relationship between markers of guideline compliance and temporal trends. The objective of the study was to evaluate trends in OHCA survival over an 8-year period that included the implementation of the 2005 and 2010 international cardiopulmonary resuscitation (CPR) guidelines. METHODS AND RESULTS: This was a population-based cohort study of all consecutive treated OHCA patients of presumed cardiac cause between 2006 and 2013 in the City of Toronto, Canada, and surrounding regions. Temporal changes were measured by χ2 trend test. The association between year of the OHCA and survival was evaluated using logistic regression and joinpoint analysis. A total of 23 619 patients with OHCA met study inclusion criteria. During the study period, survival to hospital discharge doubled (4.8% in 2006 to 9.4% in 2013; P<0.0001), and survival with good neurological outcome increased (6.2% in 2010 to 8.5% in 2013; P=0.005). Improvements occurred in the rates of bystander CPR and automated external defibrillator application, high-quality CPR metrics, and in-hospital targeted temperature management. After adjusting for the Utstein variables, survival to hospital discharge (odds ratio, 1.12; 95% confidence interval, 1.09-1.15) and survival with good neurological outcome (odds ratio, 1.13; 95% confidence interval, 1.05-1.22) increased with each year of study. CONCLUSIONS: Survival after OHCA has improved over time. This trend was associated with improved rates of bystander CPR, automated external defibrillator use, high-quality CPR metrics, and in-hospital targeted temperature management. The results suggest that multiple factors, each improving over time, may have contributed to the observed increase in survival.

Effects of intra-resuscitation antiarrhythmic administration on rearrest occurrence and intra-resuscitation ECG characteristics in the ROC ALPS trial.

BACKGROUND: Intra-resuscitation antiarrhythmic drugs may improve resuscitation outcomes, in part by avoiding rearrest, a condition associated with poor out-of-hospital cardiac arrest (OHCA) outcomes. However, antiarrhythmics may also alter defibrillation threshold. The objective of this study was to investigate the relationship between rearrest and intra-resuscitation antiarrhythmic drugs in the context of the Resuscitation Outcomes Consortium (ROC) amiodarone, lidocaine, and placebo (ALPS) trial. HYPOTHESIS: Rearrest rates would be lower in cases treated with amiodarone or lidocaine, versus saline placebo, prior to first return of spontaneous circulation (ROSC). We also hypothesized antiarrhythmic effects would be quantifiable through analysis of the prehospital electrocardiogram. METHODS: We conducted a secondary analysis of the ROC ALPS trial. Cases that first achieved prehospital ROSC after randomized administration of study drug were included in the analysis. Rearrest, defined as loss of pulses following ROSC, was ascertained from emergency medical services records. Rearrest rate was calculated overall, as well as by ALPS treatment group. Multivariable logistic regression models were constructed to assess the association between treatment group and rearrest, as well as rearrest and both survival to hospital discharge and survival with neurologic function. Amplitude spectrum area, median slope, and centroid frequency of the ventricular fibrillation (VF) ECG were calculated and compared across treatment groups. RESULTS: A total of 1144 (40.4%) cases with study drug prior to first ROSC were included. Rearrest rate was 44.0% overall; 42.9% for placebo, 45.7% for lidocaine, and 43.0% for amiodarone. In multivariable logistic regression models, ALPS treatment group was not associated with rearrest, though rearrest was associated with poor survival and neurologic outcomes. AMSA and median slope measures of the first available VF were associated with rearrest case status, while median slope and centroid frequency were associated with ALPS treatment group. CONCLUSION: Rearrest rates did not differ between antiarrhythmic and placebo treatment groups. ECG waveform characteristics were correlated with treatment group and rearrest. Rearrest was inversely associated with survival and neurologic outcomes.

Out-of-hospital cardiac arrest survival in drug-related versus cardiac causes in Ontario: A retrospective cohort study.

BACKGROUND: Drug overdose causes approximately 183,000 deaths worldwide annually and 50,000 deaths in Canada and the United States combined. Drug-related deaths are concentrated among young people, leading to a substantial burden of disease and loss of potential life years. Understanding the epidemiology, patterns of care, and prognosis of drug-related prehospital emergencies may lead to improved outcomes. METHODS: We conducted a retrospective cohort study of out-of-hospital cardiac arrests with drug-related and presumed cardiac causes between 2007 and 2013 using the Toronto Regional RescuNet Epistry database. The primary outcome was survival to hospital discharge. We computed standardized case fatality rates, and odds ratios of survival to hospital discharge for cardiac arrests with drug-related versus presumed cardiac causes, adjusting for confounders using logistic regression. RESULTS: The analysis involved 21,497 cardiac arrests, including 378 (1.8%) drug-related and 21,119 (98.2%) presumed cardiac. Compared with the presumed cardiac group, drug-related arrest patients were younger and less likely to receive bystander resuscitation, have initial shockable cardiac rhythms, or be transported to hospital. There were no significant differences in emergency medical service response times, return of spontaneous circulation, or survival to discharge. Standardized case fatality rates confirmed that these effects were not due to age or sex differences. Adjusting for known predictors of survival, drug-related cardiac arrest was associated with increased odds of survival to hospital discharge (OR1.44, 95%CI 1.15-1.81). INTERPRETATION: In out-of-hospital cardiac arrest, patients with drug-related causes are less likely than those with presumed cardiac causes to receive bystander resuscitation or have an initial shockable rhythm, but are more likely to survive after accounting for predictors of survival. The demographics and outcomes among drug-related cardiac arrest patients offers unique opportunities for prehospital intervention.

CPR quality during out-of-hospital cardiac arrest transport.

BACKGROUND: Previous studies have demonstrated significant associations between cardiopulmonary resuscitation (CPR) quality metrics and survival to hospital discharge. No adequately powered study has explored the relationship between location of resuscitation (scene vs. transport) and CPR quality. METHODS: We analyzed CPR quality data from treated adult OHCA occurring over a 40 month period beginning January 1, 2013 from the Rescu Epistry-cardiac arrest database. High quality CPR was defined as chest compression fraction (CCF) >0.7, compression rate >100/min and compression depth >5.0cm. Our primary objective was to compare the proportion of resuscitations for which all CPR quality benchmarks were met between scene and transport phases of resuscitation. Our secondary objectives were to compare the quality of CPR between the scene phase and transport phase of resuscitation. RESULTS: The proportion of patients with high quality CPR was similar on scene compared to during transport (45.8% vs. 42.5%; ∆ 3.3 %; 95% CI: -1.4, 8.1). Regarding individual CPR metrics, median compression rate was higher on scene compared to transport (105.8 compressions per minute (cpm) vs. 102.0cpm; ∆ 3.8cpm; 95% CI: 2.5, 4.0), while median compression depth (5.56cm vs. 5.33cm; ∆ 0.23cm; 95% CI: 0.12, 0.26) and median CCF (0.95 vs. 0.87; ∆ 0.08; 95% CI: 0.07, 0.08) were higher during the transport phase. CONCLUSIONS: High quality CPR metrics were similar in both (scene and transport) locations of resuscitation. These results suggest that high quality, manual compressions can be performed by prehospital providers regardless of location.

Increased cardiac arrest survival and bystander intervention in enclosed pedestrian walkway systems.

BACKGROUND: Cities worldwide have underground or above-ground enclosed walkway systems for pedestrian travel, representing unique environments for studying out-of-hospital cardiac arrests (OHCAs). The characteristics and outcomes of OHCAs that occur in such systems are unknown. OBJECTIVE: To determine whether OHCAs occurring in enclosed pedestrian walkway systems have differing demographics, prehospital intervention, and survival outcomes compared to the encompassing city, by examining the PATH walkway system in Toronto. METHODS: We identified all atraumatic, public-location OHCAs in Toronto from April 2006 to March 2016. Exclusion criteria were obvious death, existing DNR, and EMS-witnessed OHCAs. OHCAs were classified into mutually exclusive location groups: Toronto, Downtown, and PATH-accessible. PATH-accessible OHCAs were those that occurred within the PATH system between the first basement and third floor. We analyzed demographic, prehospital intervention, and survival data using t-tests and chi-squared tests. RESULTS: We identified 2172 OHCAs: 1752 Toronto, 371 Downtown, and 49 PATH-accessible. Compared to Toronto, a significantly higher proportion of PATH-accessible OHCAs was bystander-witnessed (62.6% vs 83.7%, p=0.003), had bystander CPR (56.6% vs 73.5%, p=0.019), bystander AED use (11.0% vs 42.6%, p<0.001), shockable initial rhythm (45.5% vs 72.9%, p<0.001), and overall survival (18.5% vs 33.3%, p=0.009). Similar significant differences were observed when compared to Downtown. CONCLUSIONS: This study suggests that OHCAs in enclosed pedestrian walkway systems are uniquely different from other public settings. Bystander resuscitation efforts are significantly more frequent and survival rates are significantly higher. Urban planners in similar infrastructure systems worldwide should consider these findings when determining AED placement and public engagement strategies.

Compression-to-ventilation ratio and incidence of rearrest-A secondary analysis of the ROC CCC trial.

BACKGROUND: Previous work has demonstrated that when out-of-hospital cardiac arrest (OHCA) patients achieve return of spontaneous circulation (ROSC), but subsequently have another cardiac arrest prior to hospital arrival (rearrest), the probability of survival to hospital discharge is significantly decreased. Additionally, few modifiable factors for rearrest are known. We sought to examine the association between rearrest and compression-to-ventilation ratio during cardiopulmonary resuscitation (CPR) and to confirm the association between rearrest and outcomes. HYPOTHESIS: Rearrest incidence would be similar between cases treated with 30:2 or continuous chest compression (CCC) CPR, but inversely related to survival and good neurological outcome. METHODS: We conducted a secondary analysis of a large randomized-controlled trial of CCC versus 30:2 CPR for the treatment of OHCA between 2011 and 2015 among 8 sites of the Resuscitation OUTCOMES: Consortium (ROC). Patients were randomized through an emergency medical services (EMS) agency-level cluster randomization design to receive either 30:2 or CCC CPR. Case data were derived from prehospital patient care reports, digital defibrillator files, and hospital records. The primary analysis was an as-treated comparison of the proportion of patients with a rearrest for patients who received 30:2 versus those who received CCC. In addition, we assessed the association between rearrest and both survival to hospital discharge and favorable neurological outcome (Modified Rankin Score≤3) in patients with and without ROSC upon ED arrival using multivariable logistic regression adjusting for age, sex, initial rhythm and measures of CPR quality. RESULTS: There were 14,109 analyzable cases that were determined to have definitively received either CCC or 30:2 CPR. Of these, 4713 had prehospital ROSC and 2040 (43.2%) had at least one rearrest. Incidence of rearrest was not significantly different between patients receiving CCC and 30:2 (44.1% vs 41.8%; adjusted OR: 1.01; 95% CI: 0.88, 1.16). Rearrest was significantly associated with lower survival (23.3% vs 36.9%; adjusted OR: 0.46; 95%CI: 0.36-0.51) and worse neurological outcome (19.4% vs 30.2%; adjusted OR: 0.46; 95%CI: 0.38, 0.55). CONCLUSION: Rearrest occurrence was not significantly different between patients receiving CCC and 30:2, and was inversely associated with survival to hospital discharge and MRS.

Long-term clinical outcomes and predictors for survivors of out-of-hospital cardiac arrest.

AIMS: Improvement in resuscitation efforts has translated to an increasing number of survivors after out-of-hospital cardiac arrest (OHCA). Our objectives were to assess the long-term outcomes and predictors of mortality for patients who survived OHCA. METHODS: We conducted a population-based cohort study linking the Toronto RescuNET cardiac arrest database with administrative databases in Ontario, Canada. We included patients with non-traumatic OHCA from December 1, 2005 to December 31, 2014. The primary outcomes were mortality at 1 year and 3 years. Cox proportional hazard models were constructed to evaluate the predictors of mortality. RESULTS: Among the 28,611 OHCA patients who received treatment at the scene of arrest, 1591 patients survived to hospital discharge. During hospitalization, 36% received coronary revascularizations and 27% received an implantable cardioverter defibrillator. At one year after discharge, 12.6% of patients had died and 37.3% were readmitted. At 3 years, mortality rate was 20% and all-cause readmission rate was 54.1%. Older age and a history of cancer were associated with higher risk of 3-year mortality. Shockable rhythm at presentation (hazard ratio [HR] 0.62, 95% CI 0.45-0.85), use of coronary revascularization (HR 0.37, 95% CI 0.28-0.51) or implantable cardioverter defibrillator (HR 0.28, 95% CI 0.20-0.41) was associated with substantially lower 3-year mortality. Prior cardiac conditions and other arrest characteristics were not associated with long-term mortality. CONCLUSIONS: Survivors of OHCA face significant morbidity and mortality after hospital discharge. Clinical trials are needed to evaluate the potential benefits of invasive cardiac procedures in OHCA survivors.