Background: Previous studies have demonstrated that earlier epinephrine administration is associated with improved survival from out-of-hospital cardiac arrest (OHCA) with shockable initial rhythms. However, the effect of epinephrine timing on patients with nonshockable initial rhythms is unclear. The objective of this study was to measure the association between time to epinephrine administration and survival in adults and children with emergency medical services (EMS)–treated OHCA with nonshockable initial rhythms.

Methods: We performed a secondary analysis of OHCAs prospectively identified by the Resuscitation Outcomes Consortium network from June 4, 2011, to June 30, 2015. We included patients of all ages with an EMS-treated OHCA and an initial nonshockable rhythm. We excluded those with return of spontaneous circulation in <10 minutes. We conducted a subgroup analysis involving patients <18 years of age. The primary exposure was time (minutes) from arrival of the first EMS agency to the first dose of epinephrine. Secondary exposure was time to epinephrine dichotomized as early (<10 minutes) or late (≥10 minutes). The primary outcome was survival to hospital discharge. We adjusted for Utstein covariates and Resuscitation Outcomes Consortium study site.

Results: From 55 568 EMS-treated OHCAs, 32 101 patients with initial nonshockable rhythms were included. There were 12 238 in the early group, 14 517 in the late group, and 5346 not treated with epinephrine. After adjusting for potential confounders, each minute from EMS arrival to epinephrine administration was associated with a 4% decrease in odds of survival for adults, odds ratio=0.96 (95% confidence interval, 0.95–0.98). A subgroup analysis (n=13 290) examining neurological outcomes showed a similar association (adjusted odds ratio, 0.94 per minute; 95% confidence interval, 0.89–0.98). When epinephrine was given late in comparison with early, odds of survival were 18% lower (odds ratio, 0.82; 95% confidence interval, 0.68–0.98). In a pediatric analysis (n=595), odds of survival were 9% lower (odds ratio, 0.91; 95% confidence interval, 0.81–1.01) for each minute delay in epinephrine.

Conclusions: Among OHCAs with nonshockable initial rhythms, the majority of patients were administered epinephrine >10 minutes after EMS arrival. Each minute delay in epinephrine administration was associated with decreased survival and unfavorable neurological outcomes. EMS agencies should consider strategies to reduce epinephrine administration times in patients with initial nonshockable rhythms.

背景：先前的研究表明，早期肾上腺素的给药可以改善院外心脏骤停（OHCA）并具有令人震惊的初始节律，从而提高生存率。但是，尚不清楚肾上腺素时机对最初的不可节律患者的影响。这项研究的目的是测量在急诊医疗服务（EMS）治疗的OHCA成人和儿童中，肾上腺素给药时间与存活率之间的相关性。

方法：我们对从2011年6月4日至2015年6月30日由复苏结果联盟网络预先确定的OHCA进行了二级分析。我们纳入了所有年龄段接受EMS治疗的OHCA且初始不可电击的患者。我们排除了<10分钟内自发性循环恢复的患者。我们进行了<18岁患者的亚组分析。主要暴露时间是从第一个EMS代理商到达第一剂肾上腺素的时间（分钟）。二次暴露是将肾上腺素的时间分为早期（<10分钟）或晚期（≥10分钟）。主要结局是出院生存。我们针对Utstein协变量和复苏成果联盟研究站点进行了调整。

结果：从55 568 EMS治疗的OHCA中，纳入了32 101例具有最初不可电击的节律的患者。早期组有12 238例，晚期组有14 517例，未用肾上腺素治疗的有5346例。在对潜在的混杂因素进行调整后，从EMS到肾上腺素给药的每一分钟，成年人的生存几率降低4％，几率比= 0.96（95％置信区间，0.95-0.98）。一项检查神经系统结果的亚组分析（n = 13 290）显示出相似的关联（调整后的优势比，每分钟0.94； 95％置信区间，0.89-0.98）。与早期相比，肾上腺素给药较晚，生存几率降低了18％（赔率，0.82； 95％的置信区间，0.68-0.98）。在儿科分析中（n = 595），生存几率降低了9％（几率0.91； 95％置信区间0.81–1）。

结论：在最初节律不可改变的OHCA中，大多数患者在EMS到达后10分钟以上给予肾上腺素。肾上腺素给药的每分钟延迟都与存活率降低和神经系统不良结局有关。EMS机构应考虑采取策略以减少最初无法电击的节律患者的肾上腺素给药时间。