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.

Background: The impact of dispatcher‐assisted bystander cardiopulmonary resuscitation ( CPR ) on neurological outcomes in children is unclear. We investigated whether dispatcher‐assisted bystander CPR shows favorable neurological outcomes (Cerebral Performance Category scale 1 or 2) in children with out‐of‐hospital cardiac arrest ( OHCA ). Methods and Results: Children (n=5009, age<18 years) with OHCA were selected from a nationwide Utstein‐style Japanese database (2008–2010) and divided into 3 groups: no bystander CPR (n=2287); bystander CPR with dispatcher instruction (n=2019); and bystander CPR without dispatcher instruction (n=703) groups. The primary endpoint was favorable neurological outcome at 1 month post‐ OHCA . Dispatcher CPR instruction was offered to 53.9% of patients, significantly increasing bystander CPR provision rate (adjusted odds ratio [ aOR ], 7.51; 95% confidence interval [ CI ], 6.60 to 8.57). Bystander CPR with and without dispatcher instruction were significantly associated with improved 1‐month favorable neurological outcomes (aOR, 1.81 and 1.68; 95% CI, 1.24 to 2.67 and 1.07 to 2.62, respectively), compared to no bystander CPR. Conventional CPR was associated with increased odds of 1‐month favorable neurological outcomes irrespective of etiology of cardiac arrest ( aOR , 2.30; 95% CI, 1.56 to 3.41). However, chest‐compression‐only CPR was not associated with 1‐month meaningful outcomes ( aOR , 1.05; 95% CI , 0.67 to 1.64). Conclusions: In children with OHCA , dispatcher‐assisted bystander CPR increased bystander CPR provision rate and was associated with improved 1‐month favorable neurological outcomes, compared to no bystander CPR . Conventional bystander CPR was associated with greater likelihood of neurologically intact survival, compared to chest‐compression‐only CPR, irrespective of cardiac arrest etiology.

Introduction: Few clinical trials have provided evidence that epinephrine administration after out-of-hospital cardiac arrest (OHCA) improves long-term survival. Here we determined whether prehospital epinephrine administration would improve 1-month survival in OHCA patients. Methods: We analyzed the data of 209,577 OHCA patients; the data were prospectively collected in a nationwide Utstein-style Japanese database between 2009 and 2010. Patients were divided into the initial shockable rhythm (n = 15,492) and initial non-shockable rhythm (n = 194,085) cohorts. The endpoints were prehospital return of spontaneous circulation (ROSC), 1-month survival, and 1-month favorable neurological outcomes (cerebral performance category scale, category 1 or 2) after OHCA. We defined epinephrine administration time as the time from the start of cardiopulmonary resuscitation (CPR) by emergency medical services personnel to the first epinephrine administration. Results: In the initial shockable rhythm cohort, the ratios of prehospital ROSC, 1-month survival, and 1-month favorable neurological outcomes in the non-epinephrine group were significantly higher than those in the epinephrine group (27.7% vs. 22.8%, 27.0% vs. 15.4%, and 18.6% vs. 7.0%, respectively; all P < 0.001). However, in the initial non-shockable rhythm cohort, the ratios of prehospital ROSC and 1-month survival in the epinephrine group were significantly higher than those in the non-epinephrine group (18.7% vs. 3.0% and 3.9% vs. 2.2%, respectively; all P < 0.001) and there was no significant difference between the epinephrine and non-epinephrine groups for 1-month favorable neurological outcomes (P = 0.62). Prehospital epinephrine administration for OHCA patients with initial non-shockable rhythms was independently associated with prehospital ROSC (adjusted odds ratio [aOR], 8.83, 6.18, 4.32; 95% confidence interval [CI], 8.01-9.73, 5.82-6.56, 3.98-4.69; for epinephrine administration times ≤9 min, 10-19 min, and ≥20 min, respectively), with improved 1-month survival when epinephrine administration time was <20 min (aOR, 1.78, 1.29; 95% CI, 1.50-2.10, 1.17-1.43; for epinephrine administration times ≤9 min and 10-19 min, respectively), and with deteriorated 1-month favorable neurological outcomes (aOR, 0.63, 0.49; 95% CI, 0.48-0.80, 0.32-0.71; for epinephrine administration times 10-19 min and ≥20 min, respectively). Conclusions: Prehospital epinephrine administration for OHCA patients with initial nonshockable rhythms was independently associated with achievement of prehospital ROSC and had association with improved 1-month survival when epinephrine administration time was <20 min.

Introduction: The 2010 cardiopulmonary resuscitation guidelines recommend emergency medical services (EMS) personnel consider prehospital termination-of-resuscitation (TOR) rules for out-of-hospital cardiac arrest (OHCA) following basic life support and/or advanced life support efforts in the field. However, the rate of implementation of international TOR rules is still low. Here, we aimed to develop and validate a new TOR rule for emergency department physicians to replace the international TOR rules for EMS personnel in the field. This rule aims to guide physicians in deciding whether to withhold further resuscitation attempts or terminate on-going resuscitation immediately after patient arrival. Methods: We analyzed data prospectively collected in a nationwide Utstein-style Japanese database between 2005 and 2009, from 495,607 adult patients with OHCA. Patients were divided into development (n = 390,577) and validation (n = 105,030) groups. The main outcome measures were specificity, positive predictive value (PPV), and area under the receiver operating characteristic (ROC) curve for the newly developed TOR rule. Results: We developed a new TOR rule that includes 3 criteria based on the results of multivariate logistic regression analysis for predicting a 1-month death after OHCA: no prehospital return of spontaneous circulation (adjusted odds ratio [OR], 25.8; 95% confidence interval [CI], 24.7–26.9), unshockable initial rhythm (adjusted OR, 2.76; 95% CI, 2.54–3.01), and unwitnessed by bystanders (adjusted OR, 2.18; 95% CI, 2.09–2.28). The specificity, PPV, and area under the ROC curve for this new TOR rule for predicting 1-month death in the validation group were 0.903 (95% CI, 0.894–0.911), 0.993 (95% CI, 0.992–0.993), and 0.874 (95% CI, 0.872–0.876), respectively. Conclusions: We developed and validated a new TOR rule for emergency department physicians consisting of 3 prehospital variables (no prehospital ROSC, unshockable initial rhythm, and unwitnessed by bystanders) that is a >99% predictor of very poor outcome. However, the implementation of this new rule in other countries or EMS systems requires further validation studies.

Background The response time of emergency medical services (EMS) is an important determinant of survival after out‐of‐hospital cardiac arrest. We sought to identify upper limits of EMS response times and bystander interventions associated with neurologically intact survival. Methods and Results We analyzed the records of 553 426 patients with out‐of‐hospital cardiac arrest in a Japanese registry between 2010 and 2014. The primary study end point was 1‐month neurologically intact survival (Cerebral Performance Category scale 1 or 2). Increased EMS response time was associated with significantly decreased adjusted odds of 1‐month neurologically intact survival (adjusted odds ratio [aOR] for each 1‐minute increase, 0.89; 95% confidence interval [CI], 0.89–0.90), although this relationship was modified by bystander interventions. The bystander interventions and the ranges of EMS response times that were associated with increased adjusted 1‐month neurologically intact survival were as follows: bystander defibrillation, from ≤2 minutes (aOR, 3.10 [95% CI, 1.25–7.31]) to 13 minutes (aOR, 5.55 [95% CI, 2.66–11.2]); bystander conventional cardiopulmonary resuscitation, from 3 minutes (aOR 1.48 [95% CI, 1.02–2.12]) to 11 minutes (aOR 2.41 [95% CI, 1.61–3.56]); and bystander chest‐compression‐only cardiopulmonary resuscitation, from ≤2 minutes (aOR 1.57 [95% CI, 1.01–2.25]) to 11 minutes (aOR 1.92 [95% CI, 1.45–2.56]). However, the increase in neurologically intact survival of those receiving bystander interventions became statistically insignificant compared with no bystander interventions when the EMS response time was outside these ranges. Conclusions The upper limits of the EMS response times associated with improved 1‐month neurologically intact survival were 13 minutes when bystanders provided defibrillation (typically with cardiopulmonary resuscitation) and 11 minutes when bystanders provided cardiopulmonary resuscitation without defibrillation.

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.