The effect of time to defibrillation and targeted temperature management on functional survival after out-of-hospital cardiac arrest

Application of Machine Learning for Patients With Cardiac Arrest: Systematic Review and Meta-Analysis

BACKGROUND

Currently, there is a lack of effective early assessment tools for predicting the onset and development of cardiac arrest (CA). With the increasing attention of clinical researchers on machine learning (ML), some researchers have developed ML models for predicting the occurrence and prognosis of CA, with certain models appearing to outperform traditional scoring tools. However, these models still lack systematic evidence to substantiate their efficacy.

OBJECTIVE

This systematic review and meta-analysis was conducted to evaluate the prediction value of ML in CA for occurrence, good neurological prognosis, mortality, and the return of spontaneous circulation (ROSC), thereby providing evidence-based support for the development and refinement of applicable clinical tools.

METHODS

PubMed, Embase, the Cochrane Library, and Web of Science were systematically searched from their establishment until May 17, 2024. The risk of bias in all prediction models was assessed using the Prediction Model Risk of Bias Assessment Tool.

RESULTS

In total, 93 studies were selected, encompassing 5,729,721 in-hospital and out-of-hospital patients. The meta-analysis revealed that, for predicting CA, the pooled C-index, sensitivity, and specificity derived from the imbalanced validation dataset were 0.90 (95% CI 0.87-0.93), 0.83 (95% CI 0.79-0.87), and 0.93 (95% CI 0.88-0.96), respectively. On the basis of the balanced validation dataset, the pooled C-index, sensitivity, and specificity were 0.88 (95% CI 0.86-0.90), 0.72 (95% CI 0.49-0.95), and 0.79 (95% CI 0.68-0.91), respectively. For predicting the good cerebral performance category score 1 to 2, the pooled C-index, sensitivity, and specificity based on the validation dataset were 0.86 (95% CI 0.85-0.87), 0.72 (95% CI 0.61-0.81), and 0.79 (95% CI 0.66-0.88), respectively. For predicting CA mortality, the pooled C-index, sensitivity, and specificity based on the validation dataset were 0.85 (95% CI 0.82-0.87), 0.83 (95% CI 0.79-0.87), and 0.79 (95% CI 0.74-0.83), respectively. For predicting ROSC, the pooled C-index, sensitivity, and specificity based on the validation dataset were 0.77 (95% CI 0.74-0.80), 0.53 (95% CI 0.31-0.74), and 0.88 (95% CI 0.71-0.96), respectively. In predicting CA, the most significant modeling variables were respiratory rate, blood pressure, age, and temperature. In predicting a good cerebral performance category score 1 to 2, the most significant modeling variables in the in-hospital CA group were rhythm (shockable or nonshockable), age, medication use, and gender; the most significant modeling variables in the out-of-hospital CA group were age, rhythm (shockable or nonshockable), medication use, and ROSC.

CONCLUSIONS

ML represents a currently promising approach for predicting the occurrence and outcomes of CA. Therefore, in future research on CA, we may attempt to systematically update traditional scoring tools based on the superior performance of ML in specific outcomes, achieving artificial intelligence-driven enhancements.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD42024518949; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=518949.

Occult Ventricular Fibrillation Visualized by Echocardiogram During Cardiac Arrest: A Retrospective Observational Study From the Real-Time Evaluation and Assessment for Sonography-Outcomes Network (REASON)

Objectives

Cardiac arrest patients with a shockable rhythm are more likely to survive an out-of-hospital cardiac arrest (OHCA) compared with a nonshockable rhythm. An electrocardiogram (ECG) is the most common way to identify a shockable rhythm, but it can miss patients with clinically significant ventricular fibrillation (vfib). We sought to determine the percentage of nonshockable OHCA patients that demonstrated vfib on echo.

Methods

Secondary analysis of echo images recorded from a prior study from our group, Real-Time Evaluation and Assessment for Sonography-Outcomes Network (REASON), a multicenter, observational study of OHCA patients presenting to the emergency department with nonshockable rhythms. Using ECG and echocardiogram images recorded during the initial cardiopulmonary resuscitation (CPR) pause, 2 independent emergency physicians determined the presence of vfib. Two experienced emergency physicians (R.G. and T.G.) reviewed echo images with adjudication by a third if necessary. ECG interpretation was unblinded to patient information. The primary outcome was the proportion of patients in occult vfib.

Results

During the first CPR pause, reviewers noted occult vfib in 22/685 (3.2%; 95% CI, 2.1%-4.8%) subjects. Patients with ECG vfib (n = 55) were defibrillated immediately during the first pause in CPR, but no patients with occult vfib during the first pause in CPR were defibrillated. Subsequently, 50% (11 of 22) of occult vfib patients were defibrillated when ECG vfib was recognized during an ensuing pause in CPR.

Conclusion

One in 33 OHCAs with a nonshockable ECG rhythm exhibits VF on echocardiogram. Patients presenting to the emergency department in a presumed nonshockable rhythm following OHCA may benefit from prompt defibrillation if personnel recognize occult vfib on echo.

The impact of locked cabinets for automated external defibrillators (AEDs) on cardiac arrest and AED outcomes: A scoping review

Background

Rapid public defibrillation with automated external defibrillators (AEDs) is critical to improving out-of-hospital cardiac arrest survival. Concerns about AED theft and vandalism have led to implementing security measures, including locked cabinets. This scoping review, conducted as part of the evidence review for the International Liaison Committee on Resuscitation, explores the impact of securing AEDs in locked cabinets.

Methods

Searches of Medline, Embase, Cochrane, CINAHL (from database inception to 25/5/2024) and Google Scholar (first 200 articles). Studies of any type or design, published with an English abstract, examining the impact of locked AED cabinets were included. The included studies were grouped by outcomes, and an iterative narrative synthesis was performed.

Results

We screened 2,096 titles and found 10 relevant studies: 8 observational studies (4 published as conference abstracts) and 2 simulation studies. No study reported patient outcomes. Studies reported data on between 36 and 31,938 AEDs. Most studies reported low rates (<2%) of theft/missing/vandalism, including AEDs that were accessible 24/7. The only study comparing unlocked and locked cabinets showed minimal difference in theft and vandalism rates (0.3% vs. 0.1%). Two simulation studies showed significantly slower AED retrieval when additional security measures, included locked cabinets, were used. A survey of first responders reported half (25/50) were injured while accessing an AED that required breaking glass to access.

Conclusion

The limited literature suggests that vandalism and the loss of AEDs are rare and occur in locked and unlocked cabinets. Research on this topic is needed that focuses on real-life retrieval and patient outcomes.

Out-of-hospital cardiac arrest outcomes' determinants: an Italian retrospective cohort study based on Lombardia CARe

This study on the Lombardia Cardiac Arrest Registry (Lombardia CARe,) the most complete nationwide out-of-hospital cardiac arrest (OHCA) registry in Italy, aims at evaluating post-OHCA intra-hospital mortality risk according to patient's characteristics and emergency health service management (EMS), including level of care of first-admission hospital. Out of 12,581 patients included from 2015 to 2022, we considered 1382 OHCA patients admitted alive to hospital and survived more than 24 h. We estimated risk ratios (RRs) of intra-hospital mortality through log-binomial regression models adjusted by patients' and EMS characteristics. The study population consisted mainly of males (66.6%) most aged 60-69 years (24.7%) and 70-79 years (23.7%). Presenting rhythm was non-shockable in 49.9% of patients, EMS intervention time was less than 10 min for 30.3% of patients, and cardiopulmonary resuscitation (CPR) was performed for less than 15 min in 29.9%. Moreover, 61.6% of subjects (n = 852) died during hospital admission. Intra-hospital mortality is associated with non-shockable presenting rhythm (RR 1.27, 95% CI 1.19-1.35) and longer CPR time (RR 1.39, 95% CI 1.28-1.52 for 45 min or more). Patients who accessed to a secondary vs tertiary care hospital were more frequently older, with a non-shockable presenting rhythm and longer EMS intervention time. Non-shockable presenting rhythm accounts for 27% increased risk of intra-hospital death in OHCA patients, independently of first-access hospital level, thus demonstrating that patients' outcomes depend only by intrinsic OHCA characteristics and Health System's resources are utilised as efficiently as possible.

Insights from coronial recommendations for preventing natural deaths in sport and recreation in Québec, Canada

Introduction

This descriptive retrospective study analyzed coronial recommendations for natural deaths in sport and recreation from January 2006 to December 2019 using data from the Bureau du coroner du Québec.

Methods

Reports with recommendations were analyzed by sex, age group, cause of death, context, and activity. The nature of recommendations was assessed using a public health-based model. Thematic analysis was conducted following a four-phase approach in which themes developed were emphasized and further connected with existing literature.

Results

Reports involving individuals aged 18-24 and reports related to ice hockey were significantly more likely to contain recommendations. Reports related to individuals ≥45 years old, or related to cycling or hunting had higher death frequencies, but relatively low recommendation rates. Most recommendations aligned with the public health-based model but specifying implementation time frames was rare (11.7%). Nearly 60% of coroner's recommendations focused on automated external defibrillator implementation, delivery and training.

Discussion

Mitigation of sudden cardiac arrest risk for individuals ≥45 years old, timely treatment of life-threatening arrhythmias especially for activity practiced in remote regions and specifying implementation time frames were identified as improvement areas. The multi-faceted approach to enhancing public access defibrillation developed by the International Liaison Committee on Resuscitation in 2022 addresses recurrent themes covered by coroners and holds the potential to inform evidence-based decision making.

The American Heart Association Emergency Cardiovascular Care 2030 Impact Goals and Call to Action to Improve Cardiac Arrest Outcomes: A Scientific Statement From the American Heart Association

Every 10 years, the American Heart Association (AHA) Emergency Cardiovascular Care Committee establishes goals to improve survival from cardiac arrest. These goals align with broader AHA Impact Goals and support the AHA's advocacy efforts and strategic investments in research, education, clinical care, and quality improvement programs. This scientific statement focuses on 2030 AHA emergency cardiovascular care priorities, with a specific focus on bystander cardiopulmonary resuscitation, early defibrillation, and neurologically intact survival. This scientific statement also includes aspirational goals, such as establishing cardiac arrest as a reportable disease and mandating reporting of standardized outcomes from different sources; advancing recognition of and knowledge about cardiac arrest; improving dispatch system response, availability, and access to resuscitation training in multiple settings and at multiple time points; improving availability, access, and affordability of defibrillators; providing a focus on early defibrillation, in-hospital programs, and establishing champions for debriefing and review of cardiac arrest events; and expanding measures to track outcomes beyond survival. The ability to track and report data from these broader aspirational targets will potentially require expansion of existing data sets, development of new data sets, and enhanced integration of technology to collect process and outcome data, as well as partnerships of the AHA with national, state, and local organizations. The COVID-19 (coronavirus disease 2019) pandemic, disparities in COVID-19 outcomes for historically excluded racial and ethnic groups, and the longstanding disparities in cardiac arrest treatment and outcomes for Black and Hispanic or Latino populations also contributed to an explicit focus and target on equity for the AHA Emergency Cardiovascular Care 2030 Impact Goals.

Pre-Arrival Care of the Out-of-Hospital Cardiac Arrest Victim

Lay rescuers play a pivotal role in the recognition and initial management of out-of-hospital cardiac arrest. The provision of timely pre-arrival care by lay responders, including cardiopulmonary resuscitation and the use of automated external defibrillator before emergency medical service arrival, is important link in the chain of survival and has been shown to improve outcomes from cardiac arrest. Although physicians are not directly involved in bystander response to cardiac arrest, they play a key role in emphasizing the importance of bystander interventions.

The association of the post-resuscitation on-scene interval and patient outcomes after out-of-hospital cardiac arrest

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.

Impact of defibrillation with automated external defibrillator by bystander before defibrillation by emergency medical system personnel on neurological outcome of out-of-hospital cardiac arrest with non-cardiac etiology

Aim of the study

Although defibrillation using automated external defibrillator (AED) by bystander prior to emergency medical system (EMS) arrival was associated with favorable outcomes in out-of-hospital cardiac arrest (OHCA) of cardiac cause, whether it improves outcomes of OHCA due to non-cardiac cause is not clear. We aimed to investigate the impact of defibrillation with AED by bystander before defibrillation by EMS personnel on the outcomes of OHCA of presumed non-cardiac cause.

Methods

This was a retrospective cohort study using the All-Japan Utstein registry (reference period: 2013 to 2017). We included adult patients with OHCA of presumed non-cardiac cause, who had initial shockable rhythm, and who received witnessed arrest bystander cardiopulmonary resuscitation (CPR). Exposure variable was defibrillation with AED by bystander in comparison with initial defibrillation by EMS. Logistic regression analyses were conducted to assess the association between bystander AED shock and favorable neurological outcome (Cerebral Performance Category scale 1 or 2) at one month.

Results

Among the 1,053 patients included for analysis, 57 (5.4%) received bystander AED shock. There was no statistically significant difference in the rate of favorable neurological outcome at one month between groups [9 (15.8%) vs 109 (10.9%), p = 0.26]. Logistic regression analysis adjusted for characteristics, intervention, and time course of CPR showed no association between bystander AED shock and favorable neurological outcome [OR (95% CI): 1.63 (0.70-3.77), p = 0.25].

Conclusion

In this study, defibrillation with AED by bystander before defibrillation by EMS personnel was not associated with the favorable outcomes of OHCA of presumed non-cardiac cause.

Current summary of the evidence in drone-based emergency medical services care

Interventions for many medical emergencies including cardiac arrests, strokes, drug overdoses, seizures, and trauma, are critically time-dependent, with faster intervention leading to improved patient outcomes. Consequently, a major focus of emergency medical services (EMS) systems and prehospital medicine has been improving the time until medical intervention in these time-sensitive emergencies, often by reducing the time required to deliver critical medical supplies to the scene of the emergency. Medical indications for using unmanned aerial vehicles, or drones, are rapidly expanding, including the delivery of time-sensitive medical supplies. To date, the drone-based delivery of a variety of time-critical medical supplies has been evaluated, generating promising data suggesting that drones can improve the time interval to intervention through the rapid delivery of automatic external defibrillators (AEDs), naloxone, antiepileptics, and blood products. Furthermore, the improvement in the time until intervention offered by drones in out-of-hospital emergencies is likely to improve patient outcomes in time-dependent medical emergencies. However, barriers and knowledge gaps remain that must be addressed. Further research demonstrating functionality in real-world scenarios, as well as research that integrates drones into the existing EMS structure will be necessary before drones can reach their full potential. The primary aim of this review is to summarize the current evidence in drone-based Emergency Medical Services Care to help identify future research directions.

Optimizing Outcomes After Out-of-Hospital Cardiac Arrest With Innovative Approaches to Public-Access Defibrillation: A Scientific Statement From the International Liaison Committee on Resuscitation

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Optimizing outcomes after out-of-hospital cardiac arrest with innovative approaches to public-access defibrillation: A scientific statement from the International Liaison Committee on Resuscitation

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Decreasing time to first shock: Routine application of defibrillation pads in prehospital STEMI

INTRODUCTION

Four percent of ST-elevation myocardial infarctions (STEMIs) are complicated by an out-of-hospital cardiac arrest (OHCA). Research has shown that shorter time to initial defibrillation in patients with ventricular fibrillation/tachycardia (VF/VT) arrests increases favourable neurologic survival. The purpose of this study is to determine whether routine application of defibrillation pads in patients with prehospital STEMI decreases the time to initial defibrillation in those who suffer OHCA.

METHODS

This was a health records review for adult patients diagnosed with STEMI in the prehospital setting from January 2012 to July 2016. Patients were included if they had a 12 lead ECG indicative of STEMI and subsequently suffered VF/VT OHCA while in paramedic care. This study was designed to evaluate the effects of the "pads-on" protocol in a pre (Jan 2012-May 2014) /post implementation fashion (Jun 2014- Jul 2016). Records were reviewed for relevant patient and event features. T-test was used to measure the difference between mean times to defibrillation.

RESULTS

446 patients were diagnosed with prehospital STEMI. 11 suffered OHCA while in paramedic care. The mean (SD) age was 66.0 (9.3) and 55% were female. In the 4 patients treated with the "pads-on" protocol, the mean time to initial defibrillation was 17.7 seconds, compared to 72.7 seconds in patients who had pads applied following arrest (Δ 55.0 sec [95% CI 22.7-87.2 s]).

CONCLUSION

Routine application of defibrillation pads in STEMI patients who suffer OHCA decreases time to initial defibrillation, which has previously been demonstrated to increase favourable neurologic survival.

Assessment of Canadian Public Automated External Defibrillator Registries

BACKGROUND

Public automated external defibrillator (AED) registries aim to increase layperson defibrillation for victims of out-of-hospital cardiac arrest. This study aims to characterize Canadian AED registries and the process by which these databases are updated and used.

METHODS

A survey was administered to representatives from each eligible AED registry. Collected data included information on registry management, AED validation process, linkage to emergency medical dispatch (EMD), and number of AEDs per registry. Three unregistered AEDs in each region were then located and registered into their respective registry. The primary endpoint was the proportion of AEDs that became visible in the registry within 1 month.

RESULTS

Of the 9 Canadian provinces that have registries, 7 are provincial, whereas 2 contain smaller independent registries. The survey was completed by 90% of contacted registries. The number of AEDs per registry ranged from 21 to 443 per 100,000 persons. Six registries are managed by a provincial government, 6 use a standardized validation process, and 8 are linked to EMD. Of the 21 AEDs registered by our study personnel in 7/10 registries, 9 (43%) were made available to the public within 1 month of registration. Only 1 registry employed an AED validation process that included direct contact with AED managers.

CONCLUSIONS

Canadian public AED registries demonstrate significant differences in their governance and administrative processes. A majority of registries are integrated with EMD for out-of-hospital cardiac arrest, but not all registries use a standardized validation process to ensure accuracy of AED information submitted by the public.

Development of unmanned aerial vehicle (UAV) networks delivering early defibrillation for out-of-hospital cardiac arrests (OHCA) in areas lacking timely access to emergency medical services (EMS) in Germany: a comparative economic study

OBJECTIVES

This study wants to assess the cost-effectiveness of unmanned aerial vehicles (UAV) equipped with automated external defibrillators (AED) in out-of-hospital cardiac arrests (OHCA). Especially in rural areas with longer response times of emergency medical services (EMS) early lay defibrillation could lead to a significant higher survival in OHCA.

PARTICIPANTS

3296 emergency medical stations in Germany.

SETTING

Rural areas in Germany.

PRIMARY AND SECONDARY OUTCOME MEASURES

Three UAV networks providing 80%, 90% or 100% coverage for rural areas lacking timely access to EMS (ie, time-to-defibrillation: >10 min) were developed using a location allocation analysis. For each UAV network, primary outcome was the cost-effectiveness using the incremental cost-effectiveness ratio (ICER) calculated by the ratio of financial costs to additional life years gained compared with current EMS.

RESULTS

Current EMS with 3926 emergency stations was able to gain 1224 life years on annual average in the study area. The UAV network providing 100% coverage consisted of 1933 UAV with average annual costs of €43.5 million and 1845 additional life years gained on annual average (ICER: €23 568). The UAV network providing 90% coverage consisted of 1074 UAV with average annual costs of €24.2 million and 1661 additional life years gained on annual average (ICER: €14 548). The UAV network providing 80% coverage consisted of 798 UAV with average annual costs of €18.0 million and 1477 additional life years gained on annual average (ICER: €12 158).

CONCLUSION

These results reveal the relevant life-saving potential of all modelled UAV networks. Furthermore, all analysed UAV networks could be deemed cost-effective. However, real-life applications are needed to validate the findings.

Double (dual) sequential defibrillation for refractory ventricular fibrillation cardiac arrest: A systematic review

INTRODUCTION

Cardiac arrests associated with shockable rhythms such as ventricular fibrillation or pulseless VT (VF/pVT) are associated with improved outcomes from cardiac arrest. The more defibrillation attempts required to terminate VF/pVT, the lower the survival. Double sequential defibrillation (DSD) has been used for refractory VF/pVT cardiac arrest despite limited evidence examining this practice. We performed a systematic review to summarize the evidence related to the use of DSD during cardiac arrest.

METHODS

This review was performed according to PRISMA and registered on PROSPERO (ID: CRD42020152575). We searched Embase, Pubmed, and the Cochrane library from inception to 28 February 2020. We included adult patients with VF/pVT in any setting. We excluded case studies, case series with less than five patients, conference abstracts, simulation studies, and protocols for clinical trials. We predefined our outcomes of interest as neurological outcome, survival to hospital discharge, survival to hospital admission, return of spontaneous circulation (ROSC), and termination of VF/pVT. Risk of bias was examined using ROBINS-I or ROB-2 and certainty of studies were reported according to GRADE methodology.

RESULTS

Overall, 314 studies were identified during the initial search. One hundred and thirty studies were screened during title and abstract stage and 10 studies underwent full manuscript screening, nine included in the final analysis. Included studies were cohort studies (n = 4), case series (n = 3), case-control study (n = 1) and a prospective pilot clinical trial (n-1). All studies were considered to have serious or critical risk of bias and no meta-analysis was performed. Overall, we did not find any differences in terms of neurological outcome, survival to hospital discharge, survival to hospital admission, ROSC, or termination of VF/pVT between DSD and a standard defibrillation strategy.

CONCLUSION

The use of double sequential defibrillation was not associated with improved outcomes from out-of-hospital cardiac arrest, however the current literature has a number of limitations to interpretation. Further high-quality evidence is needed to answer this important question.

Artificial neural networks improve early outcome prediction and risk classification in out-of-hospital cardiac arrest patients admitted to intensive care

Background

Pre-hospital circumstances, cardiac arrest characteristics, comorbidities and clinical status on admission are strongly associated with outcome after out-of-hospital cardiac arrest (OHCA). Early prediction of outcome may inform prognosis, tailor therapy and help in interpreting the intervention effect in heterogenous clinical trials. This study aimed to create a model for early prediction of outcome by artificial neural networks (ANN) and use this model to investigate intervention effects on classes of illness severity in cardiac arrest patients treated with targeted temperature management (TTM).

Methods

Using the cohort of the TTM trial, we performed a post hoc analysis of 932 unconscious patients from 36 centres with OHCA of a presumed cardiac cause. The patient outcome was the functional outcome, including survival at 180 days follow-up using a dichotomised Cerebral Performance Category (CPC) scale with good functional outcome defined as CPC 1–2 and poor functional outcome defined as CPC 3–5. Outcome prediction and severity class assignment were performed using a supervised machine learning model based on ANN.

Results

The outcome was predicted with an area under the receiver operating characteristic curve (AUC) of 0.891 using 54 clinical variables available on admission to hospital, categorised as background, pre-hospital and admission data. Corresponding models using background, pre-hospital or admission variables separately had inferior prediction performance. When comparing the ANN model with a logistic regression-based model on the same cohort, the ANN model performed significantly better (p = 0.029). A simplified ANN model showed promising performance with an AUC above 0.852 when using three variables only: age, time to ROSC and first monitored rhythm. The ANN-stratified analyses showed similar intervention effect of TTM to 33 °C or 36 °C in predefined classes with different risk of a poor outcome.

Conclusion

A supervised machine learning model using ANN predicted neurological recovery, including survival excellently, and outperformed a conventional model based on logistic regression. Among the data available at the time of hospitalisation, factors related to the pre-hospital setting carried most information. ANN may be used to stratify a heterogenous trial population in risk classes and help determine intervention effects across subgroups.

Improving Access to Automated External Defibrillators in Rural and Remote Settings: A Drone Delivery Feasibility Study

Background Time to treatment is critical for survival from sudden cardiac arrest. Every minute delay in defibrillation results in a 7% to 10% reduction in survival. This is particularly problematic in rural and remote regions, where emergency medical service response is prolonged and automated external defibrillators (AEDs) are often not available. Our primary objective was to examine the feasibility of a novel AED drone delivery method for rural and remote sudden cardiac arrest. A secondary objective was to compare response times between AED drone delivery and ambulance to mock sudden cardiac arrest resuscitations. Methods and Results We conducted 6 simulations in 2 rural communities in southern Ontario, Canada. In the first 2 simulations, the drone and ambulance were dispatched from the same paramedic base. In simulations 3 and 4, the drone and ambulance were dispatched from separate paramedic bases; and in simulations 5 and 6, the drone was dispatched from an optimized location. During each simulation, a "mock" call was placed to 911 and a single AED drone and an ambulance were simultaneously dispatched to a predetermined destination. On scene, trained first responders retrieved the AED from the drone and initiated resuscitative efforts on a mannequin until paramedics arrived. No difficulties were encountered during drone activation by dispatch, ascent, landing, or bystander retrieval of the AED from the drone. During simulations 1 and 2, the distance to the scene was 6.6 km. For simulations 3 and 4, the ambulance response distance increased to 8.8 km while drone remained at 6.6 km; and in simulations 5 and 6, the ambulance response distance was 20 km compared with 9 km for the drone. During each flight, the AED drone arrived on scene before the ambulance, between 1.8 and 8.0 minutes faster. Conclusions This study suggests AED drone delivery is feasible, with the potential for improvements in response time during simulated sudden cardiac arrest scenarios. Further research is required to determine the appropriate system configuration for AED drone delivery in an integrated emergency medical service system as well as optimal strategies to simplify bystander application of a drone-delivered AED.

Difficulties in undertaking research in acutely ill cardiac patients

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Hypothermic to ischemic ratio and mortality in post-cardiac arrest patients

BACKGROUND

We studied the associations between ischemia and hypothermia duration, that is, the hypothermic to ischemic ratio (H/I ratio), with mortality in patients included in a trial on two durations of targeted temperature management (TTM) at 33°C.

METHODS

The TTH48 (NCT01689077) trial compared 24 and 48 hours of TTM in patients after cardiac arrest. We calculated the hypothermia time from return of spontaneous circulation (ROSC) until the patient reached 37°C after TTM and the ischemic time from CA to ROSC. We compared continuous variables with the Mann-Whitney U test. Using COX regression, we studied the independent association of the logarithmically transformed H/I ratio and time to death as well as interaction between time to ROSC, hypothermia duration, and intervention group. We visualized the predictive ability of variables with receiver operating characteristic curve analysis.

RESULTS

Of the 338 patients, 237 (70%) survived for 6 months. The H/I ratio was 155 (IQR 111-238) in survivors and 114 (IQR 80-169) in non-survivors (P < .001). In a Cox regression model including factors associated with outcome in univariate analysis, the logarithmically transformed H/I ratio was a significant predictor of outcome (hazard ratio 0.52 (0.37-0.72, P = .001)). After removing an outlier, we found no interaction between time to ROSC and intervention group (P = .55) or hypothermia duration in quartiles (P = .07) with mortality. There was no significant difference in the area under the curve (AUC) between time to ROSC and H/I ratio (ΔAUC 0.03 95% CI -0.006-0.07, P = .10).

CONCLUSIONS

We did not find any consistent evidence of a modification of the effect of TTM based on ischemia duration.

Temporal trends in the use of targeted temperature management after cardiac arrest and association with outcome: insights from the Paris Sudden Death Expertise Centre

Purpose

Recent doubts regarding the efficacy may have resulted in a loss of interest for targeted temperature management (TTM) in comatose cardiac arrest (CA) patients, with uncertain consequences on outcome. We aimed to identify a change in TTM use and to assess the relationship between this change and neurological outcome.

Methods

We used Utstein data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (capturing CA data from all secondary and tertiary hospitals located in the Great Paris area, France) between May 2011 and December 2017. All cases of non-traumatic OHCA patients with stable return of spontaneous circulation (ROSC) were included. After adjustment for potential confounders, we assessed the relationship between changes over time in the use of TTM and neurological recovery at discharge using the Cerebral Performance Categories (CPC) scale.

Results

Between May 2011 and December 2017, 3925 patients were retained in the analysis, of whom 1847 (47%) received TTM. The rate of good neurological outcome at discharge (CPC 1 or 2) was higher in TTM patients as compared with no TTM (33% vs 15%, P < 0.001). Gender, age, and location of CA did not change over the years. Bystander CPR increased from 55% in 2011 to 73% in 2017 (P < 0.001) and patients with a no-flow time longer than 3 min decreased from 53 to 38% (P < 0.001). The use of TTM decreased from 55% in 2011 to 37% in 2017 (P < 0.001). Meanwhile, the rate of patients with good neurological recovery remained stable (19 to 23%, P = 0.76). After adjustment, year of CA occurrence was not associated with outcome.

Conclusions

We report a progressive decrease in the use of TTM in post-cardiac arrest patients over the recent years. During this period, neurological outcome remained stable, despite an increase in bystander-initiated resuscitation and a decrease in “no flow” duration.

Targeted temperature management guided by the severity of hyperlactatemia for out-of-hospital cardiac arrest patients: a post hoc analysis of a nationwide, multicenter prospective registry

Background

The International Liaison Committee on Resuscitation guidelines recommend target temperature management (TTM) between 32 and 36 °C for patients after out-of-hospital cardiac arrest, but did not indicate patient-specific temperatures. The association of serum lactate concentration and neurological outcome in out-of-hospital cardiac arrest patient has been reported. The study aim was to investigate the benefit of 32–34 °C in patients with various degrees of hyperlactatemia compared to 35–36 °C.

Methods

This study was a post hoc analysis of the Japanese Association for Acute Medicine out-of-hospital cardiac arrest registry between June 2014 and December 2015. Patients with complete targeted temperature management and lactate data were eligible. Patients were stratified to mild (< 7 mmol/l), moderate (< 12 mmol/l), or severe (≥ 12 mmol/l) hyperlactatemia group based on lactate concentration after return of spontaneous circulation. They were subdivided into 32–34 °C or 35–36 °C groups. The primary endpoint was an adjusted predicted probability of 30-day favorable neurological outcome, defined as a cerebral performance category score of 1 or 2.

Result

Of 435 patients, 139 had mild, 182 had moderate, and 114 had severe hyperlactatemia. One hundred and eight (78%) with mild, 128 with moderate (70%), and 83 with severe hyperlactatemia (73%) received TTM at 32–34 °C. The adjusted predicted probability of a 30-day favorable neurological outcome following severe hyperlactatemia was significantly greater with 32–34 °C (27.4%, 95% confidence interval: 22.0–32.8%) than 35–36 °C (12.4%, 95% CI 3.5–21.2%; p = 0.005). The differences in outcomes in those with mild and moderate hyperlactatemia were not significant.

Conclusions

In OHCA patients with severe hyperlactatemia, the adjusted predicted probability of 30-day favorable neurological outcome was greater with TTM at 32–34 °C than with TTM at 35–36 °C. Further evaluation is needed to determine whether TTM at 32–34 °C can improve neurological outcomes in patients with severe hyperlactatemia after out-of-hospital cardiac arrest.

Automated External Defibrillator Geolocalization with a Mobile Application, Verbal Assistance or No Assistance: A Pilot Randomized Simulation (AED G-MAP)

OBJECTIVE

Shockable rythms are common among victims of witnessed public out-of-hospital cardiac arrest (OHCA), but bystander defibrillation with a public automated external defibrillator (PAED) is rare. Instructions from the emergency medical dispatcher and mobile applications were developed to expedite the localization of PAEDs, but their effectiveness has not been compared.

METHODS

Participants were enrolled in a three-armed randomized simulation where they witnessed a simulated OHCA on a university campus, were instructed to locate a PAED and provide defibrillation. Participants were stratified and randomized to: (1) no assistance in finding the PAED, (2) assistance from a geolocalization mobile application (AED-Quebec), or (3) verbal assistance. Data collectors tracked each participant's time elapsed and distance traveled to shock.

RESULTS

Of the 52 volunteers participating in the study (46% male, mean age 37), 17 were randomized to the no assistance group, 18 to the mobile application group and 17 to the verbal group. Median (IQR) time to shock was, respectively, 10:00 min (7:49-10:00), 9:44 (6:30-10:00), and 5:23 (4:11-9:08), with statistically significant differences between the verbal group and the other groups (p ≤ 0.01). The success rate for defibrillation in <10 minutes was 35%, 56% and 76%. Multivariate regression of all participants pooled showed that knowledge of campus geography was the strongest predictor of shock in <10 minutes (aOR =14.3, 95% CI 1.85-99.9). Among participants without prior geographical knowledge, verbal assistance provided a trend towards decreased time to shock, but the differences over no assistance (7:28 vs. 10:00, p = 0.10) and over the mobile app (7:28 vs. 10:00, p = 0.11) were not statistically significant.

CONCLUSION

In a simulated environment, verbally providing OHCA bystanders with the nearest PAED's location appeared to be effective in reducing the time to defibrillation in comparison to no assistance and to an AED geolocalizing mobile app, but further research is required to confirm this hypothesis, ascertain the external validity of these results, and evaluate the real-life implications of these strategies.

Public CPR and AED Knowledge: An Opportunity for Educational Outreach in South Carolina

OBJECTIVES

Sudden cardiac arrest (SCA) remains a significant cause of morbidity and mortality, and the key to increased survival is emergent bystander intervention. A growing body of evidence has shown that timely bystander-initiated cardiopulmonary resuscitation (CPR) and defibrillation are significantly correlated with an increased likelihood of survival. Despite these demonstrated benefits, bystanders perform these interventions in less than half of witnessed SCA cases. We hypothesized that the level of public CPR and automated external defibrillator (AED) knowledge may be limited and may play a role in the likelihood of intervening.

METHODS

A convenience survey of potential bystanders to SCA was conducted in a high-traffic shopping center to estimate the overall knowledge level of CPR and AED usage and determine general attitudes toward intervening in the setting of SCA. Concurrently with the survey, professional emergency responders offered free bystander compression-only CPR and AED training on location.

RESULTS

The majority of survey respondents expressed a willingness to perform the aforementioned interventions when asked directly. Results, however, indicate that although 69% of respondents consider themselves to have a general knowledge of CPR, only 18% spontaneously mentioned CPR when presented with a hypothetical SCA scenario. In addition, only 2.2% mentioned defibrillation, and 63% indicated that they would not know how to locate a public access AED when needed. Of the individuals who participated in both the survey and the training, all of them indicated that they were more likely to intervene in an SCA after receiving the training.

CONCLUSIONS

Our findings suggest that future public outreach efforts should target the current CPR and AED knowledge gap. They also indicate that free, brief trainings offered at public events are a feasible way to increase the knowledge and skills of potential bystanders to SCA.

Is Distance to the Nearest Registered Public Automated Defibrillator Associated with the Probability of Bystander Shock for Victims of Out-of-Hospital Cardiac Arrest?

Introduction Rapid access to defibrillation is a key element in the management of out-of-hospital cardiac arrests (OHCAs). Public automated external defibrillators (PAEDs) are becoming increasingly available, but little information exists regarding the relation between the proximity to the arrest and their usage in urban areas.

METHODS

This study is a retrospective, observational, cross-sectional analysis of non-traumatic OHCA during a 24-month period in the greater Montreal area (Quebec, Canada). Using logistic regression, bystander shock odds are described with regards to distance from the OHCA scene to the nearest PAED, adjusted for prehospital care arrival delay and time of day, and stratifying for type of location.

RESULTS

Out of a total of 2,443 OHCA victims identified, 77 (3%) received bystander PAED shock, 622 (26%) occurred out-of-home, and 743 (30%) occurred during business hours. When controlling for time (business hours versus other hours) and minimum response delay for prehospital care arrival, a marginal negative association was found between bystander shock and distance to the nearest PAED in logged meters (aOR=0.80; CI, 0.64-0.99) for out-of-home cardiac arrests. No significant association was found between distance and bystander shock for at-home arrests. Out-of-home victims had significantly higher odds of receiving bystander shock up to 175 meters of distance to a PAED inclusively (aOR=2.52; CI, 1.07-5.89).

CONCLUSION

For out-of-home cardiac arrests, proximity to a PAED was associated with bystander shock in the greater Montreal area. Strategies aiming to increase accessibility and use of these life-saving devices could further expand this advantage by assisting bystanders in rapidly locating nearby PAEDs. Neves Briard J , de Montigny L , Ross D , de Champlain F , Segal E . Is distance to the nearest registered public automated defibrillator associated with the probability of bystander shock for victims of out-of-hospital cardiac arrest? Prehosp Disaster Med. 2018;33(2):153-159.

Cardiac arrest while exercising on mountains in national or provincial parks: A national observational study from 2012 to 2015

BACKGROUND

Previous studies on cardiac arrest in mountainous areas were focused on environmental features such as altitude and temperature. However, those are limited to factors affecting the prognosis of patients after cardiac arrest. We analyzed the cardiac arrests in national or provincial parks located in the mountains and determined the factors affecting the prognosis of patients after cardiac arrest.

METHODS

This study included all emergency medical service (EMS) treated patients over the age of 40 experiencing out-of-hospital cardiac arrests (OHCAs) of presumed cardiac etiology during exercise, between January 2012 and December 2015. The main focus of interest was the location of cardiac arrest occurrence (national mountain parks and provincial parks vs. other sites). The main outcome was survival to discharge and multivariable logistic regression was performed to adjust for possible confounding effects.

RESULTS

A total 1835 patients who suffered a cardiac arrest while exercising were included. From these, 68 patients experienced cardiac arrest in national or provincial parks, and 1767 occurred in other locations. The unadjusted and adjusted ORs (95% CI) for a good cerebral performance scale (CPC) were 0.09 (0.01-0.63) and 0.08(0.01-0.56), survival discharges were 0.13(0.03-0.53) and 0.11 (0.03-0.48).

CONCLUSIONS

Cardiac arrests occurring while exercising in the mountainous areas have worse prognosis compared to alternative locations.

Use of automated chest compression devices after out-of-hospital cardiac arrest in Sweden

OBJECTIVE

To evaluate the implementation of automated chest compression cardiopulmonary resuscitation (ACC-CPR) after out-of-hospital cardiac arrest (OHCA) in Sweden during the years 2011 through 2015. The association between ACC-CPR and 30-day survival was studied as a secondary objective.

METHODS

The Swedish cardiopulmonary resuscitation registry is a prospectively recorded nationwide registry of modified Utstein parameters including all patients with attempted resuscitation after OHCA. Propensity score matching (PSM) was used to adjust for known confounders in the secondary analysis.

RESULTS

Of the 24,316 patients included in the study population, 32.4% received ACC-CPR, with substantial regional variation ranging from 0.8% to 78.8%. Male gender and an initial shockable rhythm were associated with ACC-CPR, whereas crew witnessed status was associated with manual CPR. Potential markers of prolonged resuscitation attempts (drug administration and endotracheal intubation) were more prevalent in the ACC-CPR group. The unadjusted 30-day survival rate was 6.3% for ACC-CPR patients. The adjusted odds ratio for 30-day survival regarding use of an ACC device was 0.72 (95% CI 0.62-0.84, p<0.001, n=13922).

CONCLUSION

The use of ACC devices varied significantly between Swedish regions and overall survival to 30days was low among patients receiving ACC-CPR. Although measured and unmeasured confounding might explain our finding of lower survival rates for patients exposed to ACC-CPR, specific guidelines recommending when and how ACC-CPR should be used are warranted as there might be circumstances where these devices do more harm than good.

Observed survival benefit of mild therapeutic hypothermia reanalysing the Circulation Improving Resuscitation Care trial

BACKGROUND

Mild therapeutic hypothermia is argued being beneficial for outcome after cardiac arrest.

MATERIALS AND METHODS

Retrospective analysis of Circulation Improving Resuscitation Care (CIRC) trial data to assess if therapeutic cooling to 33 ± 1 °C core temperature had an association with survival. Of 4231 adult, out-of-hospital cardiac arrests of presumed cardiac origin initially enrolled, eligibility criteria for therapeutic hypothermia were met by 1812. Logistic regression was undertaken in a stepwise fashion to account for the impact on outcome of each significant difference and for the variable of interest between the groups.

RESULTS

Out-of- and in-hospital cooled were 263 (15%), only after admission cooled were 230 (13%) and not cooled were 357 (20%) patients. The group cooled out of- and in hospital had 98 (37%) survivors as compared to the groups cooled in hospital only [80 (35%)] and of those not cooled [68 (19%)]. After adjusting for known covariates (sex, age, witnessed cardiac arrest, no- and low-flow time, shockable initial rhythm, random allocation, bystander cardiopulmonary resuscitation and percutaneous coronary intervention), the odds ratio for survival comparing no cooling to out-of- plus in-hospital cooling was 0·53 [95% confidence interval (CI): 0·46-0·61, P < 0·001], and comparing to in-hospital cooling only was 0·67 (95% CI: 0·50-0·89, P = 0·006).

CONCLUSION

Mild therapeutic hypothermia initiated out of hospital and/or in hospital was associated with improved survival within this secondary analysis of the CIRC cohort compared to no therapeutic hypothermia.

Time to Cooling Is Associated with Resuscitation Outcomes

Our purpose was to analyze evidence related to timing of cooling from studies of targeted temperature management (TTM) after return of spontaneous circulation (ROSC) after cardiac arrest and to recommend directions for future therapy optimization. We conducted a preliminary review of studies of both animals and patients treated with post-ROSC TTM and hypothesized that a more rapid cooling strategy in the absence of volume-adding cold infusions would provide improved outcomes in comparison with slower cooling. We defined rapid cooling as the achievement of 34°C within 3.5 hours of ROSC without the use of volume-adding cold infusions, with a ≥3.0°C/hour rate of cooling. Using the PubMed database and a previously published systematic review, we identified clinical studies published from 2002 through 2014 related to TTM. Analysis included studies with time from collapse to ROSC of 20–30 minutes, reporting of time from ROSC to target temperature and rate of patients in ventricular tachycardia or ventricular fibrillation, and hypothermia maintained for 20–24 hours. The use of cardiopulmonary bypass as a cooling method was an exclusion criterion for this analysis. We compared all rapid cooling studies with all slower cooling studies of ≥100 patients. Eleven studies were initially identified for analysis, comprising 4091 patients. Two additional studies totaling 609 patients were added based on availability of unpublished data, bringing the total to 13 studies of 4700 patients. Outcomes for patients, dichotomized into faster and slower cooling approaches, were determined using weighted linear regression using IBM SPSS Statistics software. Rapid cooling without volume-adding cold infusions yielded a higher rate of good neurological recovery than slower cooling methods. Attainment of a temperature below 34°C within 3.5 hours of ROSC and using a cooling rate of more than 3°C/hour appear to be beneficial.

Targeted temperature management for adult out-of-hospital cardiac arrest: current concepts and clinical applications

Targeted temperature management (TTM) (primarily therapeutic hypothermia (TH)) after out-of-hospital cardiac arrest (OHCA) has been considered effective, especially for adult-witnessed OHCA with a shockable initial rhythm, based on pathophysiology and on several clinical studies (especially two randomized controlled trials (RCTs) published in 2002). However, a recently published large RCT comparing TTM at 33 °C (TH) and TTM at 36 °C (normothermia) showed no advantage of 33 °C over 36 °C. Thus, this RCT has complicated the decision to perform TH after cardiac arrest. The results of this RCT are sometimes interpreted fever control alone is sufficient to improve outcomes after cardiac arrest because fever control was not strictly performed in the control groups of the previous two RCTs that showed an advantage for TH. Although this may be possible, another interpretation that the optimal target temperature for TH is much lower than 33 °C may be also possible. Additionally, there are many points other than target temperature that are unknown, such as the optimal timing to initiate TTM, the period between OHCA and initiating TTM, the period between OHCA and achieving the target temperature, the duration of maintaining the target temperature, the TTM technique, the rewarming method, and the management protocol after rewarming. RCTs are currently underway to shed light on several of these underexplored issues. In the present review, we examine how best to perform TTM after cardiac arrest based on the available evidence.

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.

Therapeutic hypothermia after nonshockable cardiac arrest: the HYPERION multicenter, randomized, controlled, assessor-blinded, superiority trial

BACKGROUND

Meta-analyses of nonrandomized studies have provided conflicting data on therapeutic hypothermia, or targeted temperature management (TTM), at 33°C in patients successfully resuscitated after nonshockable cardiac arrest. Nevertheless, the latest recommendations issued by the International Liaison Committee on Resuscitation and by the European Resuscitation Council recommend therapeutic hypothermia. New data are available on the adverse effects of therapeutic hypothermia, notably infectious complications. The risk/benefit ratio of therapeutic hypothermia after nonshockable cardiac arrest is unclear.

METHODS

HYPERION is a multicenter (22 French ICUs) trial with blinded outcome assessment in which 584 patients with successfully resuscitated nonshockable cardiac arrest are allocated at random to either TTM between 32.5 and 33.5°C (therapeutic hypothermia) or TTM between 36.5 and 37.5°C (therapeutic normothermia) for 24 hours. Both groups are managed with therapeutic normothermia for the next 24 hours. TTM is achieved using locally available equipment. The primary outcome is day-90 neurological status assessed by the Cerebral Performance Categories (CPC) Scale with dichotomization of the results (1 + 2 versus 3 + 4 + 5). The primary outcome is assessed by a blinded psychologist during a semi-structured telephone interview of the patient or next of kin. Secondary outcomes are day-90 mortality, hospital mortality, severe adverse events, infections, and neurocognitive performance. The planned sample size of 584 patients will enable us to detect a 9% absolute difference in day-90 neurological status with 80% power, assuming a 14% event rate in the control group and a two-sided Type 1 error rate of 4.9%. Two interim analyses will be performed, after inclusion of 200 and 400 patients, respectively.

DISCUSSION

The HYPERION trial is a multicenter, randomized, controlled, assessor-blinded, superiority trial that may provide an answer to an issue of everyday relevance, namely, whether TTM is beneficial in comatose patients resuscitated after nonshockable cardiac arrest. Furthermore, it will provide new data on the tolerance and adverse events (especially infectious complications) of TTM at 32.5-33.5°C.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01994772 .