Termination-of-resuscitation rule for emergency department physicians treating out-of-hospital cardiac arrest patients: an observational cohort study

Potential kidney donors among patients with out-of-hospital cardiac arrest and a termination of resuscitation rule

IMPORTANCE

Uncontrolled donation after circulatory determination of death (uDCD) has been developed and can serve as a source of kidneys for transplantation, especially when considering patients that meet extended criteria donation (ECD).

OBJECTIVE

This study assessed the theorical size and characteristics of the potential pool of kidney transplants from uDCD with standard criteria donation (SCD) and ECD among patients who meet Termination of Resuscitation (TOR) criteria following Out of Hospital Cardiac Arrest (OHCA).

METHODS AND PARTICIPANTS

This study focused on adult patients experiencing unexpected OHCA, who were prospectively enrolled in the Parisian registry from May 16th, 2011, to December 31st, 2020.

RESULTS

During the study period, EMS attempted resuscitation for 19,976 OHCA patients, of which 64.5% (12,890) had no return of spontaneous circulation. Among them, 47.4% (9,461) had TOR criteria, representing no chance of survival, and from them, 8.8% (1,764) met SCD criteria and could be potential organ donors and 33.6% (6,720) met ECD for kidney donors. The mean potential number per year of uDCD candidates with SCD and ECD remain stable respectively around 98 (±10.8) and 672 (±103.8) cases per year. Elderly patients (≥65 y.o.) represented 61.2% (n = 5,763/9,461) of patients who met TOR and 100% (5763/5763) of patients who could have matched both ECD criteria and TOR.

CONCLUSION AND RELEVANCE

Implementing uDCD program including SCD and ECD for kidney transplantation among OHCA cases quickly identified by the TOR, holds significant potential to substantially broaden the pool of organ donors. These programs could offer a viable solution to address the pressing burden of kidney shortage, particularly benefiting elderly recipients who may otherwise face prolonged waiting times and limited access to suitable organs.

Validation of Utstein-Based score to predict return of spontaneous circulation (UB-ROSC) in patients with out-of-hospital cardiac arrest

BACKGROUND AND AIMS

The Utstein Based-ROSC (UB-ROSC) score has been developed to predict ROSC in OHCA victims. Aim of the study was to validate the UB-ROSC score using two Utstein-based OHCA registries: the SWiss REgistry of Cardiac Arrest (SWISSRECA) and the Lombardia Cardiac Arrest Registry (Lombardia CARe), northern Italy.

METHODS

Consecutive patients with OHCA of any etiology occurring between January 1st, 2019 and December 31st 2021 were included in this retrospective validation study. UB-ROSC score was computed for each patient and categorized in one of three subgroups: low, medium or high likelihood of ROSC according to the UB-ROSC cut-offs (≤-19; -18 to 12; ≥13). To assess the performance of the UB-ROSC score in this new cohort, we assessed both discrimination and calibration. The score was plotted against the survival to hospital admission.

RESULTS

A total of 12.577 patients were included in the study. A sustained ROSC was obtained in 2.719 patients (22%). The UB-ROSC model resulted well calibrated and showed a good discrimination (AUC 0.71, 95% CI 0.70-0.72). In the low likelihood subgroup of UB-ROSC, only 10% of patients achieved ROSC, whereas the proportion raised to 36% for a score between -18 and 12 (OR 5.0, 95% CI 2.9-8.6, p < 0.001) and to 85% for a score ≥13 (OR 49.4, 95% CI 14.3-170.6, p < 0.001).

CONCLUSIONS

UB-ROSC score represents a reliable tool to predict ROSC probability in OHCA patients. Its application may help the medical decision-making process, providing a realistic stratification of the probability for ROSC.

Manual Chest Compression versus Automated Chest Compression Device during Day-Time and Night-Time Resuscitation Following Out-of-Hospital Cardiac Arrest: A Retrospective Historical Control Study

OBJECTIVE

We assessed the effectiveness of automated chest compression devices depending on the time of admission based on the frequency of iatrogenic chest injuries, the duration of in-hospital resuscitation efforts, and clinical outcomes among out-of-hospital cardiac arrest (OHCA) patients.

METHODS

We conducted a retrospective historical control study of OHCA patients in Japan between 2015-2022. The patients were divided according to time of admission, where day-time was considered 07:00-22:59 and night-time 23:00-06:59. These patients were then divided into two categories based on the in-hospital cardiopulmonary resuscitation (IHCPR) device: manual chest compression (mCC) group and automatic chest compression devices (ACCD) group. We used univariate and multivariate ordered logistic regression models adjusted for pre-hospital confounders to evaluate the impact of ACCD use during IHCPR on outcomes (IHCPR duration, CPR-related chest injuries, and clinical outcomes) in the day-time and night-time groups.

RESULTS

Among 1101 patients with OHCA (day-time, 809; night-time, 292), including 215 patients who underwent ACCD during IHCPR in day-time (26.6%) and 104 patients in night-time group (35.6%), the multivariate model showed a significant association of ACCD use with the outcomes of in-hospital resuscitation and higher rates of return in spontaneous circulation, lower incidence of CPR-related chest injuries, longer in-hospital resuscitation durations, greater survival to Emergency Department and hospital discharge, and greater survival with good neurological outcome to hospital discharge, though only in the night-time group.

CONCLUSIONS

Patients who underwent ACCD during in-hospital resuscitation at night had a significantly longer duration of in-hospital resuscitation, a lower incidence of CPR-related chest injuries, and better outcomes.

Changes in pre- and in-hospital management and outcomes among children with out-of-hospital cardiac arrest between 2012 and 2017 in Kanto, Japan

Previously, the SOS-KANTO 2012 studies, conducted in the Kanto area of Japan, reported a summary of outcomes in patients with out-of-hospital cardiac arrest (OHCA). This sub-analysis of the SOS-KANTO study 2017 aimed to evaluate the neurological outcomes of paediatric OHCA patients, by comparing the SOS-KANTO 2012 and 2017 studies. All OHCA patients, aged < 18 years, who were transported to the participating hospitals by EMS personnel were included in both SOS-KANTO studies (2012 and 2017). The number of survival patients with favourable neurological outcomes (paediatric cerebral performance category 1 or 2) at 1 month did not improve between 2012 and 2017. There was no significant difference in achievement of pre-hospital return of spontaneous circulation (ROSC) [odds ratio (OR): 2.00, 95% confidence interval (95% CI): 0.50-7.99, p = 0.50] and favourable outcome at 1 month [OR: 0.67, 95% CI: 0.11-3.99, p = 1] between the two studies, matched by age, witnessed arrest, bystander CPR, aetiology of OHCA, and time from call to EMS arrival. Multivariable logistic regression showed no significant difference in the achievement of pre-hospital ROSC and favourable outcomes at 1 month between the two studies.

Modification of termination of resuscitation rule with compression time interval in South Korea

This study aimed to validate the predictive performance of the termination of resuscitation (TOR) rule and examine the compression time interval (CTI) as a criterion for modifying the rule. This retrospective observational study analyzed adult out-of-hospital cardiac arrest (OHCA) patients attended by emergency medical service (EMS) providers in mixed urban-rural areas in Korea in 2020 and 2021. We evaluated the predictive performance of basic life support (BLS) and the Korean Cardiac Arrest Research Consortium (KoCARC) TOR rule using the false-positive rate (FPR) and positive predictive value (PPV). We modified the age cutoff criterion and examined the CTI as a new criterion. According to the TOR rule, 1827 OHCA patients were classified into two groups. The predictive performance of the BLS TOR rule had an FPR of 11.7% (95% confidence interval (CI): 5.9-17.5) and PPV of 98.4% (97.6-99.2) for mortality, and an FPR of 3.6% (0.0-7.8) and PPV of 78.6% (75.9-81.3) for poor neurological outcomes at hospital discharge. The predictive performance of the KoCARC TOR rule had an FPR of 5.0% (1.1-8.9) and PPV of 98.9% (98.0-99.8) for mortality, and an FPR of 3.7% (0.0-7.8) and PPV of 50.0% (45.7-54.3) for poor neurological outcomes at hospital discharge. The modified cutoff value for age was 68 years, with an area under the receiver operating characteristic curve over 0.7. In the group that met the BLS TOR rule, the cutoff of the CTI for death was not determined and was 21 min for poor neurological outcomes. In the group that met the KoCARC TOR rule, the cutoff of the CTI for death and poor neurological outcomes at the time of hospital discharge was 25 min and 21 min, respectively. The BLS TOR and KoCARC TOR rules showed inappropriate predictive performance for mortality and poor neurological outcomes. However, the predictive performance of the TOR rule could be supplemented by modifying the age criterion and adding the CTI criterion of the KoCARC.

Cost-effectiveness analysis of termination-of-resuscitation rules for patients with out-of-hospital cardiac arrest

AIM

To evaluate the cost-effectiveness of practices with and without termination-of-resuscitation (TOR) rules for out-of-hospital cardiac arrest (OHCA), using an analytic model based on a nationwide population-based registry in Japan.

METHODS

A combined model using a decision tree and Markov model was developed to compare costs and treatment effectiveness of three scenarios: basic life support (BLS) TOR rules (BLS-rule scenario), advanced life support (ALS) TOR rules (ALS-rule scenario), and no TOR rules (No-rule scenario). A nationwide population-based OHCA registry from January 1 to December 31, 2019 and published data were used. Analyses were performed from healthcare payers' perspectives. Life-time incremental cost-effectiveness ratio (ICER) was determined by the difference in cost between two scenarios, divided by the difference in quality adjusted life year (QALY).

RESULTS

The OHCA registry included 126,271 patients (57.3% men; median age, 80 years). The BLS-rule scenario yielded lower cost and less QALY than the ALS-rule scenario and No-rule scenario. With reference to the BLS-rule scenario, the ICERs for the ALS-rule scenario and No-rule scenario were 81,000 and 98,762 USD per QALY, respectively. The BLS-rule scenario was cost-effective in 100% of simulations at the willingness-to-pay threshold in Japan (5 million JPY = 45,455 USD). The willingness-to-pay threshold higher than 80,000 and 204,000 USD were required for the ALS-rule scenario and No-rule scenarios, respectively, to be cost-effective.

CONCLUSION

No-rule scenario was not cost-effective compared with BLS-rule scenario within acceptable willingness-to-pay thresholds. Further research on health economics of TOR rules is warranted to support constructive discussion on implementing TOR rules.

The impact of lesion complexity on predicting mortality of coronary artery disease patients after out-of-hospital cardiac arrest

INTRODUCTION

Coronary artery disease (CAD) is the most frequent cause of out-of-hospital cardiac arrest (OHCA). Nevertheless, there have been limited studies focusing on the impact of lesion complexity on resuscitated CAD patients. The purpose of the present study was to investigate the association between coronary lesion complexity and the mortality of CAD patients after OHCA.

METHODS

From pooled database of two centers, which comprised 706 successfully resuscitated OHCA patients, 172 patients undergoing coronary angiography were retrospectively investigated. A total of 148 patients exhibited coronary stenosis on angiogram and were included in the final analysis. Baseline characteristics, pre-and post-hospital care, general status after resuscitation and angiographical findings were compared between the patients who deceased within 30 days and those who survived and the predictors of 30-day mortality were determined.

RESULTS

Ninety-four patients (63.5%) survived at 30 days. Bystander cardiopulmonary resuscitation (CPR) (Odds ratio (OR) 0.36; 95% confidence interval (CI) 0.14-0.96; P = 0.041), revascularization of coronary stenosis (OR 0.15; 95% CI 0.19-0.86; P < 0.001), GRACE risk score (OR 1.04; 95% CI 1.02-1.05; P < 0.001) and SYNTAX score (OR 1.07; 95% CI 1.01-1.13; P = 0.025) were independent predictors of 30-day mortality. As multiple predictors such as bystander CPR, GRACE score and SYNTAX score were combined, the 30-day mortality gradually deteriorated.

CONCLUSIONS

In addition to bystander CPR, GRACE score and revascularization, SYNTAX score independently predicted 30-day mortality of CAD patients after OHCA.

The predictive performance of current termination-of-resuscitation rules in patients following out-of-hospital cardiac arrest in Asian countries: A cross-sectional multicentre study

Background

Termination-of-resuscitation rules (TORRs) in out-of-hospital cardiac arrest (OHCA) patients have been applied in western countries; in Asia, two TORRs were developed and have not been externally validated widely. We aimed to externally validate the TORRs using the registry of Pan-Asian Resuscitation Outcomes Study (PAROS).

Methods

PAROS enrolled 66,780 OHCA patients in seven Asian countries from 1 January 2009 to 31 December 2012. The American Heart Association-Basic Life Support and AHA-ALS (AHA-BLS), AHA-Advanced Life Support (AHA-ALS), Goto, and Shibahashi TORRs were selected. The diagnostic test characteristics and area under the receiver operating characteristic curve (AUC) were calculated. We further determined the most suitable TORR in Asia and analysed the variable differences between subgroups.

Results

We included 55,064 patients in the final analysis. The sensitivity, specificity, negative predictive value, positive predictive value, and AUC, respectively, for AHA-BLS, AHA-ALS, Goto, Shibashi TORRs were 79.0%, 80.0%, 19.6%, 98.5%, and 0.80; 48.6%, 88.3%, 9.8%, 98.5%, and 0.60; 53.8%, 91.4%, 11.2%, 99.0%, and 0.73; and 35.0%, 94.2%, 8.4%, 99.0%, and 0.65. In countries using the Goto TORR with PPV<99%, OHCA patients were younger, had more males, a higher rate of shockable rhythm, witnessed collapse, pre-hospital defibrillation, and survival to discharge, compared with countries using the Goto TORR with PPV ≥99%.

Conclusions

There was no single TORR fit for all Asian countries. The Goto TORR can be considered the most suitable; however, a high predictive performance with PPV ≥99% was not achieved in three countries using it (Korea, Malaysia, and Taiwan).

Termination-of-resuscitation rule in the emergency department for patients with refractory out-of-hospital cardiac arrest: a nationwide, population-based observational study

Background

In Japan, emergency medical service (EMS) providers are prohibited from field termination-of-resuscitation (TOR) in out-of-hospital cardiac arrest (OHCA) patients. In 2013, we developed a TOR rule for emergency department physicians (Goto’s TOR rule) immediately after hospital arrival. However, this rule is subject to flaws, and there is a need for revision owing to its relatively low specificity for predicting mortality compared with other TOR rules in the emergency department. Therefore, this study aimed to develop and validate a modified Goto’s TOR rule by considering prehospital EMS cardiopulmonary resuscitation (CPR) duration.

Methods

We analysed the records of 465,657 adult patients with OHCA from the All-Japan Utstein registry from 2016 to 2019 and divided them into two groups: development (n = 231,363) and validation (n = 234,294). The primary outcome measures were specificity, false-positive rate (FPR), and positive predictive value (PPV) of the revised TOR rule in the emergency department for predicting 1-month mortality.

Results

Recursive partitioning analysis for the development group in predicting 1-month mortality revealed that a modified Goto’s TOR rule could be defined if patients with OHCA met the following four criteria: (1) initial asystole, (2) unwitnessed arrest by any laypersons, (3) EMS-CPR duration > 20 min, and (4) no prehospital return of spontaneous circulation (ROSC). The specificity, FPR, and PPV of the rule for predicting 1-month mortality were 99.2% (95% confidence interval [CI], 99.0–99.4%), 0.8% (0.6–1.0%), and 99.8% (99.8–99.9%), respectively. The proportion of patients who fulfilled the rule and the area under the receiver operating curve (AUC) was 27.5% (95% CI 27.3–27.7%) and 0.904 (0.902–0.905), respectively. In the validation group, the specificity, FPR, PPV, proportion of patients who met the rule, and AUC were 99.1% (95% CI 98.9–99.2%), 0.9% (0.8–1.1%), 99.8% (99.8–99.8%), 27.8% (27.6–28.0%), and 0.889 (0.887–0.891), respectively.

Conclusion

The modified Goto’s TOR rule (which includes the following four criteria: initial asystole, unwitnessed arrest, EMS-CPR duration > 20 min, and no prehospital ROSC) with a > 99% predictor of 1-month mortality is a reliable tool for physicians treating refractory OHCAs immediately after hospital arrival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03999-x.

Extracorporeal Life Support in Accidental Hypothermia with Cardiac Arrest-A Narrative Review

Severely hypothermic patients, especially suffering cardiac arrest, require highly specialized treatment. The most common problems affecting the recognition and treatment seem to be awareness, logistics, and proper planning. In severe hypothermia, pathophysiologic changes occur in the cardiovascular system leading to dysrhythmias, decreased cardiac output, decreased central nervous system electrical activity, cold diuresis, and noncardiogenic pulmonary edema. Cardiac arrest, multiple organ dysfunction, and refractory vasoplegia are indicative of profound hypothermia. The aim of these narrative reviews is to describe the peculiar pathophysiology of patients suffering cardiac arrest from accidental hypothermia. We describe the good chances of neurologic recovery in certain circumstances, even in patients presenting with unwitnessed cardiac arrest, asystole, and the absence of bystander cardiopulmonary resuscitation. Guidance on patient selection, prognostication, and treatment, including extracorporeal life support, is given.

Evaluation of initial shockable rhythm as an indicator of short no-flow time in cardiac arrest: a national registry study

BACKGROUND

The duration from collapse to initiation of cardiopulmonary resuscitation (no-flow time) is one of the most important determinants of outcomes after out-of-hospital cardiac arrest (OHCA). Initial shockable cardiac rhythm (ventricular fibrillation or ventricular tachycardia) is reported to be a marker of short no-flow time; however, there is conflicting evidence regarding the impact of initial shockable cardiac rhythm on treatment decisions. We investigated the association between initial shockable cardiac rhythm and the no-flow time and evaluated whether initial shockable cardiac rhythm can be a marker of short no-flow time in patients with OHCA.

METHODS

Patients aged 18 years and older experiencing OHCA between 2010 and 2016 were selected from a nationwide population-based Japanese database. The association between the no-flow time duration and initial shockable cardiac rhythm was evaluated. Diagnostic accuracy was evaluated using the sensitivity, specificity and positive predictive value.

RESULTS

A total of 177 634 patients were eligible for the analysis. The median age was 77 years (58.3%, men). Initial shockable cardiac rhythm was recorded in 11.8% of the patients. No-flow time duration was significantly associated with lower probability of initial shockable cardiac rhythm, with an adjusted OR of 0.97 (95% CI 0.96 to 0.97) per additional minute. The sensitivity, specificity and positive predictive value of initial shockable cardiac rhythm to identify a no-flow time of <5 min were 0.12 (95% CI 0.12 to 0.12), 0.88 (95% CI 0.88 to 0.89) and 0.35 (95% CI 0.34 to 0.35), respectively. The positive predictive values were 0.90, 0.95 and 0.99 with no-flow times of 15, 18 and 28 min, respectively.

CONCLUSIONS

Although there was a significant association between initial shockable cardiac rhythm and no-flow time duration, initial shockable cardiac rhythm was not reliable when solely used as a surrogate of a short no-flow time duration after OHCA.

External validation of simplified out-of-hospital cardiac arrest and cardiac arrest hospital prognosis scores in a Japanese population: a multicentre retrospective cohort study

BACKGROUND

The novel simplified out-of-hospital cardiac arrest (sOHCA) and simplified cardiac arrest hospital prognosis (sCAHP) scores used for prognostication of hospitalised patients have not been externally validated. Therefore, this study aimed to externally validate the sOHCA and sCAHP scores in a Japanese population.

METHODS

We retrospectively analysed data from a prospectively maintained Japanese database (January 2012 to March 2013). We identified adult patients who had been resuscitated and hospitalised after intrinsic out-of-hospital cardiac arrest (OHCA) (n=2428, age ≥18 years). We validated the sOHCA and sCAHP scores with reference to the original scores in predicting 1-month unfavourable neurological outcomes (cerebral performance categories 3-5) based on the discrimination and calibration measures of area under the receiver operating characteristic curves (AUCs) and a Hosmer-Lemeshow goodness-of-fit test with a calibration plot, respectively.

RESULTS

In total, 1985/2484 (82%) patients had a 1-month unfavourable neurological outcome. The original OHCA, sOHCA, original cardiac arrest hospital prognosis (CAHP) and sCAHP scores were available for 855/2428 (35%), 1359/2428 (56%), 1130/2428 (47%) and 1834/2428 (76%) patients, respectively. The AUCs of simplified scores did not differ significantly from those of the original scores, whereas the AUC of the sCAHP score was significantly higher than that of the sOHCA score (0.88 vs 0.81, p<0.001). The goodness of fit was poor in the sOHCA score (ν=8, χ²=19.1 and Hosmer-Lemeshow test: p=0.014) but not in the sCAHP score (ν=8, χ²=13.5 and Hosmer-Lemeshow test: p=0.10).

CONCLUSION

The performances of the original and simplified OHCA and CAHP scores in predicting neurological outcomes in successfully resuscitated OHCA patients were acceptable. With the highest availability, similar discrimination and good calibration, the sCAHP score has promising potential for clinical implementation, although further validation studies to evaluate its clinical acceptance are necessary.

Outcome Related to Level of Targeted Temperature Management in Postcardiac Arrest Syndrome of Low, Moderate, and High Severities: A Nationwide Multicenter Prospective Registry

OBJECTIVES

The optimal target temperature during targeted temperature management for patients after cardiac arrest remains under debate. The aim of this study was to evaluate the association between targeted temperature management at lower target temperatures and the neurologic outcomes among patients classified by the severity of postcardiac arrest syndrome.

DESIGN

A multicenter observational study from the out-of-hospital cardiac arrest registry of the Japanese Association for Acute Medicine, which is a nationwide prospective registry of out-of-hospital cardiac arrest patients.

SETTING

A total of 125 critical care medical centers or hospitals with an emergency care department across Japan.

PATIENTS

A total of 1,111 out-of-hospital cardiac arrest patients who had received targeted temperature management.

MEASUREMENTS AND MAIN RESULTS

We divided all 1,111 postcardiac arrest syndrome patients treated with targeted temperature management into two groups: those who received targeted temperature management at a lower target temperature (33-34°C) and those who received targeted temperature management at a higher target temperature (35-36°C). In regard to classification of the patients, we divided the patients into three categories of severity (low, moderate, and high severities) using the risk classification tool, post-Cardiac Arrest Syndrome for Therapeutic hypothermia, which was previously validated. The primary outcome was the percentage of patients with a good neurologic outcome at 30 days, and the secondary outcome was the survival rate at 30 days. Multivariate analysis showed that targeted temperature management at 33-34°C was significantly associated with a good neurologic outcome and survival at 30 days in the moderate severity (odds ratio, 1.70 [95% CI, 1.03-2.83] and 1.90 [95% CI, 1.15-3.16], respectively), but not in the patients of low or high severity (pinteraction = 0.033). Propensity score analysis also showed that targeted temperature management at 33-34°C was associated with a good neurologic outcome in the moderate-severity group (p = 0.022).

CONCLUSIONS

Targeted temperature management at 33-34°C was associated with a significantly higher rate of a good neurologic outcome in the moderate-severity postcardiac arrest syndrome group, but not in the low- or high-severity group.

Continuous flow insufflation of oxygen for cardiac arrest: Systematic review of human and animal model studies

OBJECTIVE

To synthetize the evidence regarding the effect of constant flow insufflation of oxygen (CFIO) on the rate of return of spontaneous circulation (ROSC) and other clinical outcomes during cardiac arrest (CA).

METHODS

A systematic review was performed using four databases (PROSPERO: CRD42020071960). Studies reporting on adult CA patients or on animal models simulating CA and assessing the effect of CFIO on ROSC or other clinical outcomes were considered.

RESULTS

A total of 3540 citations were identified, of which 16 studies were included. Four studies (two randomized controlled trials (RCT), two cohort studies), reported on humans while 12 studies used animal models. No meta-analysis was performed due to clinical heterogeneity. There were no differences in the ROSC (18.9% vs 20.8%, p = 0.99; 27.1% vs 21.3%, p = 0.51) and sustained ROSC rates (16.1% vs 17.3%, p = 0.81; 12.5% vs 14.9%, p = 0.73) with CFIO compared to intermitant positive pressure ventilation (IPPV) in the two human RCTs. Survival to ICU discharge was similar between CFIO (2.3%) and IPPV (2.3%) in the largest RCT (p = 0.96). Human studies were at serious or high risk of bias. In animal models' studies, ROSC rates were presented in seven RCTs. CFIO was superior to IPPV in one trial, but was associated with similar ROSC rates using different ventilation strategies in the remaining six studies.

CONCLUSIONS

No definitive association between CFIO and ROSC, sustained ROSC or survival compared to other ventilation strategies could be demonstrated. Future studies should assess CFIO effect on post-survival neurological functions and patient-important CA outcomes.

Developing a time-adaptive prediction model for out-of-hospital cardiac arrest: Results from a nationwide cohort study in Korea (Preprint)

Background

Out-of-hospital cardiac arrest (OHCA) is a serious public health issue, and predicting the prognosis of OHCA patients can assist clinicians in making decisions about the treatment of patients, use of hospital resources, or termination of resuscitation.

Objective

This study aimed to develop a time-adaptive conditional prediction model (TACOM) to predict clinical outcomes every minute.

Methods

We performed a retrospective observational study using data from the Korea OHCA Registry in South Korea. In this study, we excluded patients with trauma, those who experienced return of spontaneous circulation before arriving in the emergency department (ED), and those who did not receive cardiopulmonary resuscitation (CPR) in the ED. We selected patients who received CPR in the ED. To develop the time-adaptive prediction model, we organized the training data set as ongoing CPR patients by the minute. A total of 49,669 patients were divided into 39,602 subjects for training and 10,067 subjects for validation. We compared random forest, LightGBM, and artificial neural networks as the prediction model methods. Model performance was quantified using the prediction probability of the model, area under the receiver operating characteristic curve (AUROC), and area under the precision recall curve.

Results

Among the three algorithms, LightGBM showed the best performance. From 0 to 30 min, the AUROC of the TACOM for predicting good neurological outcomes ranged from 0.910 (95% CI 0.910-0.911) to 0.869 (95% CI 0.865-0.871), whereas that for survival to hospital discharge ranged from 0.800 (95% CI 0.797-0.800) to 0.734 (95% CI 0.736-0.740). The prediction probability of the TACOM showed similar flow with cohort data based on a comparison with the conventional model’s prediction probability.

Conclusions

The TACOM predicted the clinical outcome of OHCA patients per minute. This model for predicting patient outcomes by the minute can assist clinicians in making rational decisions for OHCA patients.

External validation of multimodal termination of resuscitation rules for out-of-hospital cardiac arrest patients in the COVID-19 era

BACKGROUND

Futile resuscitation for out-of-hospital cardiac arrest (OHCA) patients in the coronavirus disease (COVID)-19 era can lead to risk of disease transmission and unnecessary transport. Various existing basic or advanced life support (BLS or ALS, respectively) rules for the termination of resuscitation (TOR) have been derived and validated in North America and Asian countries. This study aimed to evaluate the external validation of these rules in predicting the survival outcomes of OHCA patients in the COVID-19 era.

METHODS

This was a multicenter observational study using the WinCOVID-19 Daegu registry data collected during February 18-March 31, 2020. The subjects were patients who showed cardiac arrest of presumed cardiac etiology. The outcomes of each rule were compared to the actual patient survival outcomes. The sensitivity, specificity, false positive value (FPV), and positive predictive value (PPV) of each TOR rule were evaluated.

RESULTS

In total, 170 of the 184 OHCA patients were eligible and evaluated. TOR was recommended for 122 patients based on the international basic life support termination of resuscitation (BLS-TOR) rule, which showed 85% specificity, 74% sensitivity, 0.8% FPV, and 99% PPV for predicting unfavorable survival outcomes. When the traditional BLS-TOR rules and KoCARC TOR rule II were applied to our registry, one patient met the TOR criteria but survived at hospital discharge. With regard to the FPV (upper limit of 95% confidence interval < 5%), specificity (100%), and PPV (> 99%) criteria, only the KoCARC TOR rule I, which included a combination of three factors including not being witnessed by emergency medical technicians, presenting with an asystole at the scene, and not experiencing prehospital shock delivery or return of spontaneous circulation, was found to be superior to all other TOR rules.

CONCLUSION

Among the previous nine BLS and ALS TOR rules, KoCARC TOR rule I was most suitable for predicting poor survival outcomes and showed improved diagnostic performance. Further research on variations in resources and treatment protocols among facilities, regions, and cultures will be useful in determining the feasibility of TOR rules for COVID-19 patients worldwide.

Improving Psychological Comfort of Paramedics for Field Termination of Resuscitation through Structured Training

This study examines the impact of a newly developed structured training on Singapore paramedics’ psychological comfort before the implementation of a prehospital termination of resuscitation (TOR) protocol. Following a before and after study design, the paramedics underwent a self-administered questionnaire to assess their psychological comfort level applying the TOR protocol, 22 months before and one month after a 3-h structured training session. The questionnaire addressed five domains: sociocultural attitudes on resuscitation and TOR, multi-tasking, feelings towards resuscitation and TOR, interactions with colleagues and bystanders and informing survivors. Overall psychological comfort total (PCT) scores and domain-specific scores were compared using the paired t-test with higher scores representing greater comfort. Ninety-six of the 345 eligible paramedics responded. There was no statistically significant change in the mean PCT scores at baseline and post-training; however, the “feelings towards resuscitation and TOR” domain improved by 4.77% (95% CI 1.42 to 8.13 and p = 0.006) and the multi-tasking domain worsened by 4.11% (95% CI −7.82 to −0.41 and p = 0.030). While the structured training did not impact on the overall psychological comfort levels, it led to improvements in the feelings of paramedics towards resuscitation and TOR. Challenges remain in improving paramedics’ psychological comfort levels towards TOR.

Prehospital times and outcomes of patients who had hypotension at the scene after trauma: A nationwide multicentre retrospective study

BACKGROUND

We aimed to investigate the association between prehospital times and outcomes of patients who had hypotension at the scene after trauma incidents.

METHODS

We retrospectively analysed records from a nationwide database (2004-2017) of adults (aged ≥15 years) who were hypotensive (systolic blood pressure <90 mmHg) at the scene after trauma. The endpoint was in-hospital mortality. We used multivariable logistic regression analysis to adjust for confounding factors and to estimate the odds ratio (OR) of prehospital times for in-hospital mortality. Stratified analyses were performed based on patient age and type and severity of the trauma.

RESULTS

Among 5,499 patients included, 906 (16.5%) died in the hospital. The median Injury Severity Score (ISS) was 17 (interquartile range, 9-29). There was a significant trend towards patients having higher in-hospital mortality and ISS when their prehospital times were shorter (P < 0.001). However, the association between prehospital times and in-hospital mortality was not significant after adjusting for confounding factors, with an adjusted odds ratio of 1.00 (95% confidence interval: 0.98-1.01) per 10 min increments in prehospital time. The association remained insignificant when patients were stratified according to age and type and severity of the trauma.

CONCLUSIONS

Our analysis revealed that prehospital time was not significantly associated with in-hospital mortality among patients who had hypotension at the scene after trauma in the current emergency medical service system in Japan. Further studies are needed to validate our findings.

The Sequential Organ Failure Assessment (SOFA) score predicts mortality and neurological outcome in patients with post-cardiac arrest syndrome

BACKGROUND

Patients experiencing out-of-hospital cardiac arrest (OHCA) and subsequent post-cardiac arrest syndrome are often compromised by multi-organ failure. The Sequential Organ Failure Assessment (SOFA) score has been used to predict clinical outcome of patients requiring intensive care for multi-organ failure. Thus, the assessment of SOFA score is recommended as a criterion for sepsis. Although post-cardiac arrest patients frequently develop sepsis-like status in ICU, there are limited reports evaluating the SOFA score in post-cardiac arrest patients. We investigated the predictive value of the SOFA score in survival and neurological outcomes in patients with post-cardiac arrest syndrome.

METHODS

A total of 231 cardiovascular arrest patients achieving return of spontaneous circulation (ROSC) were finally extracted from the institutional consecutive database comprised of 1218 OHCA patients transferred to the institution between January 2015 and July 2018. The SOFA score was calculated on admission and after 48h. Predictors of survival and neurological outcome defined as having cerebral-performance-category (CPC) 1 or 2 at 30 days were determined.

RESULTS

SOFA score was lower in survived patients (5.0 vs 10.0, p<0.001) and those with favorable neurological outcome (5.0 vs 8.0, p<0.001) as compared with the counterparts. The SOFA score on admission was an independent predictor of survival (OR 0.68, 95% confidence interval [CI] 0.59-0.78; p<0.001) and favorable neurological performance (OR 0.79; 95% CI 0.69-0.90; p<0.001) at 30 days. Furthermore, a change in SOFA score (48-0h) was predictive of favorable 30-day neurological outcome (OR 0.71, 95% CI 0.60-0.85; p<0.001).

CONCLUSIONS

Evaluation of the SOFA score in the ICU is useful to predict survival and neurological outcome in post-cardiac arrest patients.

Private residence as a location of cardiac arrest may have a deleterious effect on the outcomes of out-of-hospital cardiac arrest in patients with an initial non-shockable cardiac rhythm: A multicentre retrospective cohort study

AIM

We compared the outcomes between patients who experienced out-of-hospital cardiac arrest at private residences and public locations to investigate whether patient and bystander characteristics can explain the poorer outcomes of out-of-hospital cardiac arrests at private residences.

METHODS

Adult patients with intrinsic out-of-hospital cardiac arrest (n = 6,191, age ≥18 years) were selected from a prospectively collected Japanese database (January 2012 and March 2013). Patients were grouped according to arrest location into private-residence or control (e.g., public station or road, workplace, school, and other public locations) groups. The primary outcome was a favourable neurological outcome 1 month after out-of-hospital cardiac arrest.

RESULTS

The arrest location and initial cardiac rhythm had interaction effects on the outcome. After adjusting for patient and bystander characteristics and relative to the control group, a significantly poorer 1-month neurological outcome was observed in the private-residence group if the initial cardiac rhythm was non-shockable (odds ratio: 0.36, 95% confidence interval: 0.24-0.54), while it was not significant if the initial cardiac rhythm was shockable (odds ratio: 1.16, 95% confidence interval: 0.74-1.84).

CONCLUSIONS

Patients with out-of-hospital cardiac arrest at private residences had poorer outcomes than those with out-of-hospital cardiac arrest at public locations, even after adjusting for patient and bystander characteristics, if the initial cardiac rhythm was non-shockable. Our results suggest that poorer patient and bystander characteristics do not completely explain the poorer outcomes of out-of-hospital cardiac arrests; there may be unknown mechanisms through which the location of cardiac arrest affect the outcomes.

An Utstein-based model score to predict survival to hospital admission: The UB-ROSC score

AIMS

To develop and validate a multi-parametric practical score to predict the probability of survival to hospital admission of an out-of-hospital cardiac arrest (OHCA) victim by using Utstein Style-based variables.

METHODS

All consecutive OHCA cases occurring from 2015 to 2017 in two regions, Pavia Province (Italy) and Canton Ticino (Switzerland) were included. We used random effect logistic regression to model survival to hospital admission after an OHCA. We computed the model area under the ROC curve (AUC ROC) for discrimination and we performed both internal and external validation by considering all OHCAs occurring in the aforementioned regions in 2018. The Utstein-Based ROSC (UB-ROSC) score was derived by using the coefficients estimated in the regression model. The score value was obtained adding the pertinent score components calculated for each variable. The score was then plotted against the probability of survival to hospital admission.

RESULTS

1962 OHCAs were included (62% male, mean age 73 ± 16 years). Age, aetiology, location, witnessed OHCA, bystander CPR, EMS arrival time and shockable rhythm were independently associated with survival to hospital admission. The model showed excellent discrimination (AUC 0.83, 95%CI 0.81-0.85) for predicting survival to hospital admission, also at internal cross-validation (AUC 0.82, 95%CI 0.80-0.84). The model maintained good discrimination after external validation by using the 2018 OHCA cohort (AUC 0.77, 95%CI 0.74-0.80).

CONCLUSIONS

UB-ROSC score is a novel score that predicts the probability of survival to hospital admission of an OHCA victim. UB-ROSC shall help in setting realistic expectations about sustained ROSC achievement during resuscitation manoeuvres.

Effects of dispatcher-initiated telephone cardiopulmonary resuscitation after out-of-hospital cardiac arrest: A nationwide, population-based, cohort study

AIM

This study aimed to investigate the effects of dispatcher-initiated telephone cardiopulmonary resuscitation (TCPR) in Japan using a nationwide population-based registry.

METHODS

Adult Japanese patients with out-of-hospital cardiac arrest (OHCA; n = 582,483, age ≥18 years) were selected from a nationwide Utstein-style database (2010-2016) and divided into 3 groups: no bystander CPR (NCPR) before emergency medical service arrival (n = 448,606), bystander-initiated CPR (BCPR) performed without assistance (n = 46,964), and TCPR (n = 86,913). The primary outcome was a favourable neurological outcome 1 month after OHCA.

RESULTS

After adjusting for potential confounders, and relative to the NCPR group, significantly better 1-month neurological outcomes were observed in the BCPR group (odds ratio: 2.25, 95% confidence interval: 2.15-2.36; P < 0.001) and in the TCPR group (odds ratio: 1.30, 95% confidence interval: 1.24-1.36; P < 0.001). The collapse-to-CPR time was independently associated with the 1-month outcomes, with a rate of <1% for 1-month favourable neurological outcomes if CPR was initiated >5 min after the collapse.

CONCLUSION

Patients who received TCPR had significantly better outcomes than those who did not receive CPR. However, the TCPR outcomes were less favourable than those in the BCPR group. Better protocol development and enhanced education are needed to improve dispatcher instructions in Japan, which may help lessen the gap between the BCPR and TCPR outcomes and further improve the outcomes after OHCA.

Optimal extracorporeal cardiopulmonary resuscitation inclusion criteria for favorable neurological outcomes: a single-center retrospective analysis

Aim

Although age ≤75 years, witnessed arrest, shockable initial cardiac rhythm, and short cardiac arrest duration are commonly cited inclusion criteria for extracorporeal cardiopulmonary resuscitation (ECPR), these criteria are not well‐established, and ECPR outcomes remain poor. We aimed to evaluate whether the aforementioned inclusion criteria are appropriate for ECPR, and estimate the improvements in prognoses associated with their fulfillment.

Methods

Between October 2009 and December 2017, we retrospectively examined consecutive out‐of‐hospital cardiac arrest patients who were admitted to our hospital and received ECPR. We established four ECPR inclusion criteria: age ≤75 years, witnessed arrest, shockable initial cardiac rhythm, and call‐to‐hospital arrival time ≤45 min, and also evaluated the relationship between these criteria and patient outcomes.

Results

During the study period, 1,677 out‐of‐hospital cardiac arrest patients were admitted to our hospital, and 156 (9%) with ECPR were examined. The proportion of favorable neurological outcomes was 15% (24/156). However, when the study population was limited to individuals who fulfilled all four criteria, 27% (15/55) had favorable neurological outcomes; only one patient had favorable outcomes when two or more criteria were fulfilled. There was a significant positive linear correlation between the proportion of cases with favorable neurological outcomes and fulfillment of the four criteria (P = 0.005, r = 0.975).

Conclusion

Fulfillment of at least three of the aforementioned criteria could yield improved ECPR outcomes.

Pediatric Out-of-Hospital Traumatic Cardiopulmonary Arrest After Traffic Accidents and Termination of Resuscitation

STUDY OBJECTIVE

We describe the characteristics and outcomes of pediatric traumatic out-of-hospital cardiac arrest after traffic accidents and validate the termination of resuscitation clinical criteria for adult traumatic out-of-hospital cardiac arrest in pediatrics.

METHODS

We analyzed the records of pediatric (≤18 years) traumatic out-of-hospital cardiac arrest cases after traffic accidents in a prospectively collected nationwide database (2012 to 2016). Endpoints were 1-month favorable neurologic outcomes and 1-month survival. Validation of termination of resuscitation criteria, cardiac arrest at the scene, and unsuccessful resuscitation after cardiopulmonary resuscitation (CPR) greater than 15 minutes was performed based on specificity and positive predictive value.

RESULTS

Of the 582 patients who were eligible for analyses, 8 (1.4%) and 20 (3.4%) had 1-month favorable neurologic outcome and survival, respectively. All patients with favorable neurologic outcomes had out-of-hospital return of spontaneous circulation, and the duration of CPR was significantly shorter than for those with unfavorable neurologic outcomes (4 versus 23 minutes; absolute difference -21.9 minutes; 95% confidence interval -36.3 to -7.4 minutes). The duration of out-of-hospital CPR beyond which the possibility of favorable neurologic outcomes and survival diminished to less than 1% was 15 minutes. For predicting unfavorable neurologic outcomes, the termination of resuscitation criteria provided a specificity of 1.00 (95% confidence interval 0.52 to 1.00) and a positive predictive value of 1.00 (95% confidence interval 0.99 to 1.00).

CONCLUSION

The outcomes of pediatric patients with traumatic out-of-hospital cardiac arrest after traffic accidents were as poor as those of adults in previous studies. Out-of-hospital return of spontaneous circulation was a significant indicator of favorable outcomes, and the duration of out-of-hospital CPR beyond which the possibility of favorable neurologic outcomes and survival diminished to less than 1% was 15 minutes. Termination of resuscitation criteria provided an excellent positive predictive value for 1-month unfavorable neurologic outcomes after out-of-hospital cardiac arrest.

Meta-analysis of the accuracy of termination of resuscitation rules for out-of-hospital cardiac arrest

BACKGROUND

Our objective was to perform a systematic review of studies reporting the accuracy of termination of resuscitation rules (TORRs) for out-of-hospital cardiac arrest (OHCA).

METHODS

We performed a comprehensive search of the literature for studies evaluating the accuracy of TORRs, with two investigators abstracting relevant data from each study regarding study design, study quality and the accuracy of the TORRs. Bivariate meta-analysis was performed using the mada procedure in R.

RESULTS

We identified 14 studies reporting the performance of 9 separate TORRs. The sensitivity (proportion of eventual survivors for whom the TORR recommends resuscitation and transport) was generally high: 95% for the European Resuscitation Council (ERC) TORR, 97% for the basic life support (BLS) TORR and 99% for the advanced life support (ALS) TORR. The BLS and ERC TORR were more specific, which would lead to fewer futile transports, and all three of these TORRs had a miss rate of ≤0.13% (defined as a case where a patient is recommended for termination but survives). The pooled proportion of patients for whom each rule recommends TOR was much higher for the ERC and BLS TORRs (93.5% and 74.8%, respectively) than for the ALS TORR (29.0%).

CONCLUSIONS

The BLS and ERC TORRs identify a large proportion of patients who are candidates for termination of resuscitation following OHCA while having a very low rate of misclassifying eventual survivors (<0.1%). Further prospective validation of the ERC TORR and direct comparison with BLS TORR are needed.

New Termination-of-Resuscitation Models and Prognostication in Out-of-Hospital Cardiac Arrest Using Electrocardiogram Rhythms Documented in the Field and the Emergency Department

BACKGROUND

Electrocardiogram (ECG) rhythms, particularly shockable rhythms, are crucial for planning cardiac arrest treatment. There are varying opinions regarding treatment guidelines depending on ECG rhythm types and documentation times within pre-hospital settings or after hospital arrivals. We aimed to determine survival and neurologic outcomes based on ECG rhythm types and documentation times.

METHODS

This prospective observational study of 64 emergency medical centers was performed using non-traumatic out-of-hospital cardiac arrest registry data between October 2015 and June 2017. From among 4,608 adult participants, 4,219 patients with pre-hospital and hospital ECG rhythm data were enrolled. Patients were divided into 3 groups: those with initial-shockable, converted-shockable, and never-shockable rhythms. Patient characteristics and survival outcomes were compared between groups. Further, termination of resuscitation (TOR) validation was performed for 6 combinations of TOR criteria confirmed in previous studies, including 2 rules developed in the present study.

RESULTS

Total survival to discharge after cardiac arrest was 11.7%, and discharge with good neurologic outcomes was 7.9%. Survival to discharge rates and favorable neurologic outcome rates for the initial-shockable group were the highest at 35.3% and 30.2%, respectively. There were no differences in survival to discharge rates and favorable neurologic outcome rates between the converted-shockable (4.2% and 2.0%, respectively) and never-shockable groups (5.7% and 1.9%, respectively). Irrespective of rhythm changes before and after hospital arrival, TOR criteria inclusive of unwitnessed events, no pre-hospital return of spontaneous circulation, and asystole in the emergency department best predicted poor neurologic outcomes (area under the receiver operating characteristic curve of 0.911) with no patients classified as Cerebral Performance Category 1 or 2 (specificity = 1.000).

CONCLUSION

Survival outcomes and TOR predictions varied depending on ECG rhythm types and documentation times within pre-hospital filed or emergency department and should, in the future, be considered in treatment algorithms and prognostications of patients with out-of-hospital cardiac arrest.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03222999.

Differences in durations, adverse events, and outcomes of in-hospital cardiopulmonary resuscitation between day-time and night-time: An observational cohort study

BACKGROUND

Although patients with out-of-hospital cardiac arrest (OHCA) have a lower survival rate during night-time than during day-time, the cause of this difference remains unclear. We aimed to assess CPR parameters according to time period based on in-hospital cardiopulmonary resuscitation (IHCPR) duration and the frequency of iatrogenic chest injuries among OHCA patients.

METHODS

This two-centre observational cohort study evaluated non-traumatic OHCA patients who were transferred between 2013-2016. These patients were categorised according to whether they received day-time treatment (07:00-22:59) or night-time treatment (23:00-06:59). Differences in IHCPR duration, CPR-related chest injuries, return of spontaneous circulation, and survivals to emergency department and hospital discharge were compared using a generalised estimating equation model adjusted for pre-hospital confounders. Sensitivity analysis was also performed using a propensity score matching method.

RESULTS

Among 1254 patients (day-time: 948, night-time: 306), the night-time patients had a significantly shorter IHCPR duration (27.8 min vs. 23.6 min, adjusted difference: -5.1 min, 95% confidence interval [CI]: -6.7, -3.4), a higher incidence of chest injuries (40.4% vs. 67.0%, adjusted odds ratio [AOR]: 1.27, 95% CI: 1.20, 1.35), and a lower rate of return of spontaneous circulation (38.4% vs. 26.5%, AOR: 0.93, 95% CI: 0.88, 0.98). No significant differences were observed in the rates of survival to emergency department and hospital discharge. The propensity score-matched analysis revealed similar results.

CONCLUSIONS

Patients who underwent night-time treatment for OHCA had an increased risk of CPR-related chest injuries despite their shorter resuscitation duration. Further studies are needed to clarify the underlying mechanism(s).

Field termination-of-resuscitation rule for refractory out-of-hospital cardiac arrests in Japan

BACKGROUND

Guidelines for cardiopulmonary resuscitation (CPR) recommend using the universal termination-of-resuscitation (TOR) rule to identify out-of-hospital cardiac arrest (OHCA) patients eligible for field termination of resuscitation, thus avoiding medically futile transportation to the hospital. However, in Japan, emergency medical services (EMS) personnel are forbidden from terminating CPR in the field and transport almost all patients with OHCA to hospitals. We aimed to develop and validate a novel TOR rule to identify patients eligible for field termination of CPR.

METHODS

We analyzed 540,478 patients with OHCA from 2011 to 2015 using a Japanese registry. Main outcome measures were specificity and positive predictive value (PPV) of the newly developed TOR rule in predicting 1-month mortality after OHCA.

RESULTS

Recursive partitioning analysis in the development group (n=434,208) showed that EMS personnel could consider TOR if patients with OHCA met all of the following five criteria: (1) initial asystole, (2) arrest unwitnessed by a bystander, (3) age ≥81 years, (4) no bystander-administered CPR or automated external defibrillator use before EMS arrival, and (5) no return of spontaneous circulation after EMS-initiated CPR for 14min. For patients meeting these criteria, specificity and PPV for predicting 1-month mortality were 99.2% [95% confidence interval (CI), 99.0-99.3%] and 99.7% (95% CI, 99.6-99.7%), respectively, for the development group and were 99.5% (95% CI, 99.3-99.7%) and 99.8% (95% CI, 99.7-99.9%), respectively, for the validation group. Implementation of this novel rule would reduce patient transports to hospitals by 10.6% in the development group and 10.4% in the validation group.

CONCLUSIONS

Having both high specificity and PPV of >99% for predicting 1-month mortality, our developed TOR rule may be applied in the field for Japanese patients with OHCA who meet all five criteria. Prospective validation studies and establishment of prehospital EMS protocol are required before implementing this rule.

How does the length of cardiopulmonary resuscitation affect brain damage in patients surviving cardiac arrest? A systematic review

BACKGROUND

Brain injury can occur after cardiac arrest due to the effects of ischaemia and reperfusion. In serious cases this can lead to permanent disability. This risk must be considered when making decisions about terminating resuscitation. There are very specific rules for termination of resuscitation in the prehospital setting however a similar rule for resuscitation in hospital does not exist. The aim of this review was to explore the effects of duration of cardiopulmonary resuscitation on neurological outcome in survivors of both in-hospital and out-of-hospital cardiac arrest achieving return of spontaneous circulation in hospital.

METHODS

A systematic review was conducted. Five databases were searched in addition to hand searching the journals Resuscitation and Circulation and reference lists, quality of the selected studies was assessed and a narrative summary of the data presented. Studies reporting relevant outcomes were included if the participants were adults achieving return of spontaneous circulation in the hospital setting. Studies looking at additional interventions such as extracorporeal resuscitation and therapeutic hypothermia were not included. Case studies were excluded. The study period was from January 2010 to March 2016.

RESULTS

Seven cohort studies were included for review. Quality scores ranged from eight to 11 out of 12. Five of the studies found a significant association between shorter duration of resuscitation and favourable neurological outcome.

CONCLUSIONS

There is generally a better neurological outcome with a shorter duration of CPR in survivors of cardiac arrest however a cut-off beyond which resuscitation is likely to lead to unfavourable outcome could not be determined and is unlikely to exist. The findings of this review could be considered by clinicians making decisions about terminating resuscitation. This review has highlighted many gaps in the knowledge where future research is needed; a validated and reliable measure of neurological outcome following cardiac arrest, more focused research on the effects of duration on neurological outcome and further research into the factors leading to brain damage in cardiac arrest.

ABCDE of prehospital ultrasonography: a narrative review

Prehospital point-of-care ultrasound used by nonradiologists in emergency medicine is gaining ground. It is feasible on-scene and during aeromedical transport and allows health-care professionals to detect or rule out potential harmful conditions. Consequently, it impacts decision-making in prioritizing care, selecting the best treatment, and the most suitable transport mode and destination. This increasing relevance of prehospital ultrasonography is due to advancements in ultrasound devices and related technology, and to a growing number of applications. This narrative review aims to present an overview of prehospital ultrasonography literature. The focus is on civilian emergency (trauma and non-trauma) setting. Current and potential future applications are discussed, structured according to the airway, breathing, circulation, disability, and environment/exposure (ABCDE) approach. Aside from diagnostic implementation and specific protocols, procedural guidance, therapeutic ultrasound, and challenges are reviewed.

Duration of cardiopulmonary resuscitation in patients without prehospital return of spontaneous circulation after out-of-hospital cardiac arrest: Results from a severity stratification analysis

BACKGROUND

The relationship between duration of cardiopulmonary resuscitation (CPR) and post-arrest outcomes based on severity stratification in out-of-hospital cardiac arrest (OHCA) patients without prehospital return of spontaneous circulation (ROSC) remains unclear.

METHODS

We analysed 420,959 adult patients without prehospital ROSC in the All-Japan OHCA registry for 4 years. Prehospital CPR duration was defined as the time from CPR initiation by emergency medical service (EMS) providers to hospital arrival. The primary outcome was 1-month neurologically intact survival (cerebral performance category 1 or 2, CPC 1-2).

RESULTS

The rate of overall 1-month CPC 1-2 was 0.45% (1899/420,959). Using recursive partitioning analysis to predict 1-month CPC 1-2, we stratified patients into 4 groups with 3 predictors: patients aged <75 years with initial shockable rhythm (1-month CPC 1-2 rate, 6.15%), those aged ≥75 years with initial shockable rhythm (1.32%), those with EMS-witnessed arrest and initial non-shockable rhythm (1.62%), and those with EMS-unwitnessed arrest and initial non-shockable rhythm (0.15%). Prehospital CPR duration was negatively associated with 1-month CPC 1-2 (adjusted odds ratio 0.94 per 1-min increment; 95% confidence interval 0.94-0.95). Prehospital CPR durations beyond which the dynamic probability of 1-month CPC 1-2 decreased to <1% were 26 min, 10 min, 7 min, and at all times in above-mentioned stratification, respectively.

CONCLUSIONS

In OHCA patients without prehospital ROSC, those aged <75 years with initial shockable rhythm had acceptable 1-month CPC 1-2 rate. However, CPR efforts lasting 26 min or over before hospital arrival could be futile.

Improving the neurological prognosis following OHCA using real-time evaluation of cerebral tissue oxygenation

BACKGROUND

The neurological prognosis is poor for patients suffering from out-of-hospital cardiac arrest (OHCA), in the absence of bystander cardio pulmonary resuscitation (CPR), and showing asystole as the initial waveform. However, such patients have the potential of resuming social activity if cerebral tissue oxygen saturation can be preserved.

CASE PRESENTATION

We recently encountered a 60-year-old man who had suffered an OHCA in the absence of bystander CPR, and who successfully resumed complete social activity despite initial asystole and requiring at least 75min of chest compressions before return of spontaneous circulation (ROSC). In this case, chest compression was appropriately performed concurrently with real-time evaluation of cerebral tissue oxygenation using near-infrared spectroscopy (NIRS). As a result, the cerebral tissue oxygenation was well maintained, leading to resumption of social activity.

CONCLUSIONS

Improved neurological prognoses can be expected if OHCA patients with the potential for social activity resumption are identified, using NIRS, and effective cardiopulmonary and cerebral resuscitation is performed while visually checking CPR quality.

An Ethical Justification for Termination of Resuscitation Protocols for Pediatric Patients

OBJECTIVE

The aim of this article was to compare specific characteristics and outcomes among adult and pediatric out-of-hospital cardiac arrest (OHCA) patients to show that the existing literature warrants the design and implementation of pediatric studies that would specifically evaluate termination of resuscitation protocols. We also address the emotional and practical concerns associated with ceasing resuscitation efforts on scene when treating pediatric patients.

METHODS

Relevant prospective and retrospective studies were used to compare characteristics and outcomes between adult and pediatric OHCA patients. Characteristics analyzed were nonwitnessed arrests, absence of shockable rhythm, no return of spontaneous circulation, and survival to hospital discharge.

RESULTS

Cases of unwitnessed arrests by emergency medical services providers are substantially the same in pediatric patients (41.0%-96.3%) compared with their adult counterparts (47.4%-97.7%). The adult studies revealed 57.6% to 92.2% of patients without an initial shockable rhythm. The pediatric studies showed a range of 64.0% to 98.0%. The range of adult patients without return of spontaneous circulation was 54.8% to 95.4%, and the range in pediatric patients was 68.2% to 95.6%. Survival rates among the adult studies ranged from 0.8% to 9.3% (mean, 5.0%; median, 5.2%), and in the pediatric studies they were 2.0% to 26.2% (mean, 9.2%; median, 7.7%).

CONCLUSIONS

The data compared demonstrate that characteristics and outcomes are virtually identical between adult and pediatric OHCA patients. We also found the 3 chief barriers hindering further research to be invalid impediments to moving forward. This review warrants designing pediatric studies that would specifically correlate termination of resuscitation protocols with patient survival and include predictive values.

Age-Specific Differences in the Duration of Prehospital Cardiopulmonary Resuscitation Administered by Emergency Medical Service Providers Necessary to Achieve Favorable Neurological Outcome After Out-of-Hospital Cardiac Arrest

BACKGROUND

The appropriate duration of prehospital cardiopulmonary resuscitation (CPR)administered by emergency medical service (EMS) providers for patients with out-of-hospital cardiac arrest (OHCA) necessary to achieve 1-month survival with favorable neurological outcome (Cerebral Performance Category 1 or 2, CPC 1-2) is unclear and could differ by age.Methods and Results:We analyzed the records of 35,709 adult OHCA patients with return of spontaneous circulation (ROSC) before hospital arrival in a prospectively recorded Japanese registry between 2011 and 2014. The CPR duration was defined as the time from CPR initiation by EMS providers to prehospital ROSC. The rate of 1-month CPC 1-2 was 21.4% (7,650/35,709). The CPR duration was independently and inversely associated with 1-month CPC 1-2 (adjusted odds ratio, 0.93 per 1-min increment; 95% confidence interval, 0.93-0.94). The CPR duration increased with age (P<0.001). However, the CPR duration beyond which the proportion of OHCA patients with 1-month CPC 1-2 decreased to <1% declined with age: 28 min for patients aged 18-64 years, 25 min for 65-74 years, 23 min for 75-84 years, 20 min for 85-94 years, and 18 min for ≥95 years.

CONCLUSIONS

In patients who achieved prehospital ROSC after OHCA, the duration of CPR administered by EMS providers necessary to achieve 1-month CPC 1-2 varied by age.

Adult "termination-of-resuscitation" (TOR)-criteria may not be suitable for children - a retrospective analysis

Background

Only a small number of patients survive out-of-hospital-cardiac-arrest (OHCA). The duration of CPR varies considerably and transportation of patients under CPR is often unsuccessful. Termination-of-resuscitation (TOR)-criteria aim to preclude futile resuscitation efforts.

Our goal was to find out to which extent existing TOR-criteria can be transferred to paediatric OHCA-patients with special regard to their prognostic value.

Methods

We performed a retrospective analysis of an eleven-year single centre patient cohort. 43 paediatric patients admitted to our institution after emergency-medical-system (EMS)-confirmed OHCA from 2003 to 2013 were included. Morrison’s BLS- and ALS-TOR-rules as well as the Trauma-TOR-criteria by the American Association of EMS Physicians were evaluated for application in children, by calculating sensitivity, specificity, negative and positive predictive value for death-, as well as survival-prediction in our cohort.

Results

26 patients achieved ROSC and 14 were discharged alive (n = 7 PCPC 1/2, n = 7 PCPC 5). Sensitivity for BLS-TOR-criteria predicting death was 48.3%, specificity 92.9%, the PPV 93.3% and the NPV 46.4%. ALS-TOR-criteria for death had a sensitivity of 10.3%, specificity of 100%, a PPV of 100% and an NPV of 35%.

Conclusion

Retrospective application of the BLS-TOR-rule in our patient cohort identified the resuscitation of one later survivor as futile. ALS-TOR-criteria did not give false predictions of death. The proportion of CPRs that could have been abandoned is 48.2% for the BLS-TOR and only 10.3% for the ALS-TOR-rule. Both rules therefore appear not to be transferable to a paediatric population.

Duration of Prehospital Cardiopulmonary Resuscitation and Favorable Neurological Outcomes for Pediatric Out-of-Hospital Cardiac Arrests: A Nationwide, Population-Based Cohort Study

BACKGROUND

The appropriate duration of cardiopulmonary resuscitation (CPR) for pediatric out-of-hospital cardiac arrests (OHCAs) remains unclear and may differ based on initial rhythm. We aimed to determine the relationship between the duration of prehospital CPR by emergency medical services (EMS) personnel and post-OHCA outcomes.

METHODS

We analyzed the records of 12 877 pediatric patients who experienced OHCAs (<18 years of age). Data were recorded in a nationwide Japanese database between 2005 and 2012. Study end points were 30-day survival and 30-day survival with favorable neurological outcomes (Cerebral Performance Category [CPC] scale 1-2). Prehospital EMS-initiated CPR duration was defined as the time from CPR initiation by EMS personnel to prehospital return of spontaneous circulation (ROSC) or to hospital arrival when prehospital ROSC was not achieved during prehospital CPR efforts.

RESULTS

The rates of 30-day survival and 30-day CPC 1 to 2 were 9.1% (n=1167) and 2.5% (n=325), respectively. Prehospital EMS-initiated CPR duration was significantly and inversely associated with 30-day outcomes (adjusted odds ratio for 1-minute increments: 0.94, 95% confidence interval: 0.93-0.95 for survival; adjusted odds ratio: 0.90, 95% confidence interval: 0.88-0.92 for CPC 1-2). The duration of prehospital EMS-initiated CPR, beyond which the chance for favorable outcomes diminished to <1%, was 42 minutes for each key outcome, 30-day survival, and 30-day survival with CPC 1 to 2. When categorized by initial rhythm, the prehospital EMS-initiated CPR durations beyond which the chance for 30-day survival with CPC 1 to 2 diminished to <1% were 39 minutes for shockable rhythms, 42 minutes for pulseless electric activity, and 46 minutes for asystole, respectively. In patients with bystander-initiated CPR, the prehospital CPR duration, beyond which the chance for favorable outcome diminished to <1%, was 46 minutes from call receipt.

CONCLUSIONS

Prehospital EMS-initiated CPR duration for pediatric OHCAs was independently and inversely associated with 30-day favorable outcomes. The duration of prehospital EMS-initiated CPR, beyond which the chance for 30-day favorable outcomes diminished to <1%, was 42 minutes. However, the CPR duration to achieve this proportion of outcomes differed based on initial rhythm. Further research is required to elucidate appropriate CPR duration for pediatric OHCAs, including in-hospital CPR time.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT02432196.

Assessment of cardiopulmonary resuscitation practices in emergency departments for out-of-hospital cardiac arrest victims in Lebanon

BACKGROUND

The survival rate of out-of-hospital cardiac arrest (OHCA) victims in Lebanon is low. A national policy on resuscitation practice is lacking. This survey explored the practices of emergency physicians related to the resuscitation of OHCA victims in Lebanon.

METHODS

A sample of 705 physicians working in emergency departments (EDs) was recruited and surveyed using the LimeSurvey software (Carsten Schmitz, Germany). Seventy-five participants responded, yielding 10.64% response rate.

RESULTS

The most important factors in the participants' decision to initiate or continue resuscitation were presence of pulse on arrival (93.2%), underlying cardiac rhythm (93.1%), the physician's ethical duty to resuscitate (93.2%), transport time to the ED (89%), and down time (84.9%). The participants were optimistic regarding the survival of OHCA victims (58.1% reporting > 10% survival) and reported frequent resuscitation attempts in medically futile situations. The most frequently reported challenges during resuscitation decisions were related to pressure or presence of victim's family (38.8%) and lack of policy (30%).

CONCLUSION

In our setting, physicians often rely on well-established criteria for initiating/continuing resuscitation; however, their decisions are also influenced by cultural factors such as victim's family wishes. The findings support the need for a national policy on resuscitation of OHCA victims.

Improved Survival With Favorable Neurological Outcome in Elderly Individuals With Out-of-Hospital Cardiac Arrest in Japan - A Nationwide Observational Cohort Study

BACKGROUND

There is sparse data regarding the survival and neurological outcome of elderly patients with out-of-hospital cardiac arrest (OHCA).

METHODS AND RESULTS

OHCA patients (334,730) aged ≥75 years were analyzed using a nationwide, prospective, population-based Japanese OHCA database from 2008 to 2012. The overall 1-month survival with favorable neurological outcome (Cerebral Performance Category Scale, category 1 or 2; CPC 1-2) rate was 0.88%. During the study period, the annual 1-month CPC 1-2 rate in whole OHCA significantly improved (0.73% to 0.96%, P for trend <0.001). In particular, outcomes of OHCA patients aged 75 to 84 years and those aged 85 to 94 years significantly improved (0.98% to 1.28%, P for trend=0.01; 0.46% to 0.70%, P for trend <0.001, respectively). However, in OHCA patients aged ≥95 years, the outcomes did not improve. Multivariate logistic regression analysis indicated that younger age, shockable first documented rhythm, witnessed arrest, earlier emergency medical service (EMS) response time, and cardiac etiology were significantly associated with the 1-month CPC 1-2. Under these conditions, elderly OHCA patients who had cardiac etiology, shockable rhythm and had a witnessed arrest had acceptable 1-month CPC1-2 rate; 7.98% in cases where OHCA was witnessed by family, 15.2% by non-family, and 25.6% by EMS.

CONCLUSIONS

The annual 1-month CPC 1-2 rate after OHCA among elderly patients significantly improved, and the resuscitation of elderly patients in a selected population is not futile. (Circ J 2016; 80: 1153-1162).

Relationship Between the Duration of Cardiopulmonary Resuscitation and Favorable Neurological Outcomes After Out-of-Hospital Cardiac Arrest: A Prospective, Nationwide, Population-Based Cohort Study

BACKGROUND

The determination of appropriate duration of in-the-field cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) patients is one of the biggest challenges for emergency medical service providers and clinicians. The appropriate CPR duration before termination of resuscitation remains unclear and may differ based on initial rhythm. We aimed to determine the relationship between CPR duration and post-OHCA outcomes.

METHODS AND RESULTS

We analyzed the records of 17 238 OHCA patients (age ≥18 years) who achieved prehospital return of spontaneous circulation. Data were prospectively recorded in a nationwide, Japanese database between 2011 and 2012. The time from CPR initiation to prehospital return of spontaneous circulation (CPR duration) was calculated. The primary end point was 1-month survival with favorable neurological outcomes (Cerebral Performance Category [CPC] scale; CPC 1-2). The 1-month CPC 1-2 rate was 21.8% (n=3771). CPR duration was inversely associated with 1-month CPC 1-2 (adjusted unit odds ratio: 0.95, 95% CI: 0.94-0.95). Among all patients, a cumulative proportion of >99% of 1-month CPC 1-2 was achieved with a CPR duration of 35 minutes. When sorted by the initial rhythm, the CPR duration producing more than 99% of survivors with CPC 1-2 was 35 minutes for shockable rhythms and pulseless electrical activity, and 42 minutes for asystole.

CONCLUSIONS

CPR duration was independently and inversely associated with favorable 1-month neurological outcomes. The critical prehospital CPR duration for OHCA was 35 minutes in patients with initial shockable rhythms and pulseless electrical activity, and 42 minutes in those with initial asystole.

Applying the termination of resuscitation rules to out-of-hospital cardiac arrests of both cardiac and non-cardiac etiologies: a prospective cohort study

Background

The 2015 American Heart Association Guidelines for Cardiopulmonary Resuscitation recommend Basic Life Support (BLS) and Advanced Life Support (ALS) rules for termination of resuscitation (TOR). However, it is unclear whether the TOR rules are valid for out-of-hospital cardiac arrests (OHCAs) of both cardiac and non-cardiac etiologies. In this study, we validated the TOR rules for OHCA resulting from both etiologies.

Methods

This was a prospective multicenter observational study of OHCA patients transported to 67 emergency hospitals between January 2012 and March 2013 in the Kanto region of Japan. We calculated the specificity and positive predictive value (PPV) for neurologically unfavorable outcomes at one month in patients with OHCA of cardiac and non-cardiac etiologies.

Results

Of 11,505 eligible cases, 6,138 and 5,367 cases were of cardiac and non-cardiac etiology, respectively. BLS was performed on 2,818 and 2,606 patients with OHCA of cardiac and non-cardiac etiology, respectively. ALS was performed on 3,320 and 2,761 patients with OHCA of cardiac and non-cardiac etiology, respectively. The diagnostic accuracy of the TOR rules for predicting unfavorable outcomes in patients with OHCA of cardiac etiology who received BLS included a specificity of 0.985 (95 % confidence interval [CI]: 0.956–0.997) and a PPV of 0.999 (95 % CI: 0.996–1.000). In patients with OHCA from cardiac etiologies who received ALS, the TOR rules had a specificity of 0.963 (95 % CI: 0.896–0.992) and a PPV of 0.997 (95 % CI: 0.991–0.999). In patients with OHCA from non-cardiac etiologies who received BLS, the specificity was 0.915 (95 % CI: 0.796–0.976) and PPV was 0.998 (95 % CI: 0.995–0.999). For patients with OHCA from non-cardiac etiologies who received ALS, the specificity was 0.833 (95 % CI: 0.586–0.964) and PPV was 0.996 (95 % CI: 0.988–0.999).

Conclusions

Both TOR rules have high specificity and PPV in patients with OHCA from cardiac etiologies. For patients with OHCA from non-cardiac etiologies, the rules had a high PPV, but relatively low specificity. Therefore, TOR rules are useful in patients with OHCA from cardiac etiologies, but should be applied with caution to patients with OHCA from non-cardiac etiologies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1226-4) contains supplementary material, which is available to authorized users.

Can serial focussed echocardiographic evaluation in life support (FEEL) predict resuscitation outcome or termination of resuscitation (TOR)? A pilot study

AIM OF THE STUDY

This study aimed to evaluate the correlation between serial echocardiography findings and return of spontaneous circulation (ROSC) in patients with out-of-hospital cardiac arrest (OHCA) and to examine whether echocardiographic cardiac standstill duration can be used to predict ROSC.

METHODS

This was a prospective observational study of non-consecutive non-trauma adult patients with OHCA. Echocardiography was performed every 2 min during a pulse check for <10s throughout the resuscitation effort managed according to advanced life support treatment guidelines. Echocardiography findings were recorded as video clips.

RESULTS

Forty-eight patients were enrolled in the study. Serial echocardiographic cardiac standstill duration in the ROSC and no ROSC groups were 2.86 ± 2.07 min versus 20.30 ± 8.42 min, respectively (p<0.001). Cardiac standstill duration ≥10 min predicted non-ROSC with a sensitivity of 90.0%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 93.3%. A receiver operating characteristic curve was generated to determine the accuracy of serial echocardiographic cardiac standstill duration for predicting no ROSC. The area under the curve was 0.991 (p<0.000).

CONCLUSIONS

In all patients with serial echocardiographic cardiac standstill ≥10 min, no patients had ROSC. These results displayed compelling test performance and discrimination ability for subjects with and without ROSC. Our study is suggestive, and it warrants further study.

Neurological outcomes in children dead on hospital arrival

Introduction

Obtaining favorable neurological outcomes is extremely difficult in children transported to a hospital without a prehospital return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA). However, the crucial prehospital factors affecting outcomes in this cohort remain unclear. We aimed to determine the prehospital factors for survival with favorable neurological outcomes (Cerebral Performance Category 1 or 2 (CPC 1–2)) in children without a prehospital ROSC after OHCA.

Methods

Of 9093 OHCA children, 7332 children (age <18 years) without a prehospital ROSC after attempting resuscitation were eligible for enrollment. Data were obtained from a prospectively recorded Japanese national Utstein-style database from 2008 to 2012. The primary endpoint was 1-month CPC 1–2 after OHCA.

Results

The 1-month survival and 1-month CPC 1–2 rates were 6.92 % (n = 508) and 0.99 % (n = 73), respectively. The proportions of the following prehospital variables were significantly higher in the 1-month CPC 1–2 cohort than in the 1-month CPC 3–5 cohort: age (median, 3 years (interquartile range (IQR), 0–14) versus 1 year (IQR, 0–11), p <0.05), bystander-witnessed arrest (52/73 (71.2 %) versus 1830/7259 (25.2 %), p <0.001), initial ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT) rhythm (28/73 (38.3 %) versus 241/7259 (3.3 %), p <0.001), presumed cardiac causes (42/73 (57.5 %) versus 2385/7259 (32.8 %), p <0.001), and actual shock delivery (25/73 (34.2 %) versus 314/7259 (4.3 %), p <0.0001). Multivariate logistic regression analysis indicated that 2 prehospital factors were associated with 1-month CPC 1–2: initial non-asystole rhythm (VF/pulseless VT: adjusted odds ratio ( aOR), 16.0; 95 % confidence interval (CI), 8.05–32.0; pulseless electrical activity (PEA): aOR, 5.19; 95 % CI, 2.77–9.82) and bystander-witnessed arrest (aOR, 3.22; 95 % CI, 1.84–5.79). The rate of 1-month CPC 1–2 in witnessed-arrest children with an initial VF/pulseless VT was significantly higher than that in those with other initial cardiac rhythms (15.6 % versus 2.3 % for PEA and 1.2 % for asystole, p for trend <0.001).

Conclusions

The crucial prehospital factors for 1-month survival with favorable neurological outcomes after OHCA were initial non-asystole rhythm and bystander-witnessed arrest in children transported to hospitals without a prehospital ROSC.

Subsequent shock deliveries are associated with increased favorable neurological outcomes in cardiac arrest patients who had initially non-shockable rhythms

Introduction

Previous studies evaluating whether subsequent conversion to shockable rhythms in patients who had initially non-shockable rhythms was associated with altered clinical outcome reported inconsistent results. Therefore, we hypothesized that subsequent shock delivery by emergency medical service (EMS) providers altered clinical outcomes in patients with initially non-shockable rhythms.

Methods

We tested for an association between subsequent shock delivery in EMS resuscitation and clinical outcomes in patients with initially non-shockable rhythms (n = 11,481) through a survey of patients after out-of-hospital cardiac arrest in the Kanto region (SOS-KANTO) 2012 study cohort, Japan. The primary investigated outcome was 1-month survival with favorable neurological functions. The secondary outcome variable was the presence of subsequent shock delivery. We further evaluated the association of interval from initiation of cardiopulmonary resuscitation to shock with clinical outcomes.

Results

In the univariate analysis of initially non-shockable rhythms, patients who received subsequent shock delivery had significantly increased frequency of return of spontaneous circulation, 24-hour survival, 1-month survival, and favorable neurological outcomes compared to the subsequent not shocked group (P <0.0001). In the multivariate logistic regression analysis, subsequent shock was significantly associated with favorable neurological outcomes (vs. not shocked; adjusted P = 0.0020, odds ratio, 2.78; 95 % confidence interval, 1.45–5.30). Younger age, witnessed arrest, initial pulseless electrical activity rhythms, and cardiac etiology were significantly associated with the presence of subsequent shock in patients with initially non-shockable rhythms.

Conclusions

In this study of cardiac arrest patients with initially non-shockable rhythms, patients who received early defibrillation by EMS providers had increased 1-month favorable neurological outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1028-0) contains supplementary material, which is available to authorized users.