BACKGROUND In patients with out-of-hospital cardiac arrest who present with an initial shockable rhythm, a longer delay to the first shock decreases the probability of survival, often attributed to cerebral damage. The mechanisms of this decreased survival have not yet been elucidated. Estimating the probability of successful defibrillation and other factors in relation to the time to first shock may guide prehospital care systems to implement policies that improve patient survival by decreasing time to first shock. METHODS Patients with a witnessed out-of-hospital cardiac arrest and ventricular fibrillation (VF) as an initial rhythm were included using the prospective ARREST registry (Amsterdam Resuscitation Studies). Patient and resuscitation data, including time-synchronized automated external defibrillator and manual defibrillator data, were analyzed to determine VF termination at 5 seconds after the first shock. Delay to first shock was defined as the time from initial emergency call until the first shock by any defibrillator. Outcomes were the proportion of VF termination, return of organized rhythm, transportation with return of spontaneous circulation, and survival to discharge, all in relation to the delay to first shock. A Poisson regression model with robust standard errors was used to estimate the association between delay to first shock and outcomes. RESULTS Among 3723 patients, the proportion of VF termination declined from 93% when the delay to first shock was <6 minutes to 75% when that delay was >16 minutes (Ptrend<0.001). Every additional minute in VF from emergency call was associated with 6% higher probability of failure to terminate VF (adjusted relative risk, 1.06 [95% CI, 1.04-1.07]), 4% lower probability of return of organized rhythm (adjusted relative risk, 0.96 [95% CI, 0.95-0.98]), and 6% lower probability of surviving to discharge (adjusted relative risk, 0.94 [95% CI, 0.93-0.95]). CONCLUSIONS Every minute of delay to first shock was associated with a significantly lower proportion of VF termination and return of organized rhythm. This may explain the worse outcomes in patients with a long delay to defibrillation. Reducing the time interval from emergency call to first shock to ≤6 minutes could be considered a key performance indicator of the chain of survival.

中文翻译：

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在目击到院外心脏骤停的患者中，延迟首次电击与成功终止首电击心室颤动之间的关联。


背景 对于最初表现为可电击心律的院外心脏骤停患者，首次电击延迟时间越长，生存概率越低，这通常归因于脑损伤。这种生存率降低的机制尚未阐明。估计除颤成功的可能性和与首次电击时间相关的其他因素可以指导院前护理系统实施通过缩短首次电击时间来提高患者生存率的政策。方法 使用前瞻性 ARREST 登记 （阿姆斯特丹复苏研究） 纳入目睹院外心脏骤停和心室颤动 （VF） 作为初始节律的患者。分析患者和复苏数据，包括时间同步自动体外除颤器和手动除颤器数据，以确定第一次电击后 5 秒的 VF 终止。延迟到第一次电击定义为从最初的紧急呼叫到任何除颤器第一次电击的时间。结局是 VF 终止的比例、有组织心律的恢复、自主循环恢复的运输和出院存活率，所有这些都与首次电击的延迟有关。使用具有稳健标准误差的泊松回归模型来估计延迟首次休克与结果之间的关联。结果 在 3723 例患者中，VF 终止的比例从延迟至首次电击 <6 分钟时的 93% 下降到延迟为 >16 分钟时的 75% （Ptrend<0.001）。紧急呼叫导致 VF 每增加一分钟，终止 VF 失败的可能性就会增加 6%（调整后的相对风险，1.06 [95% CI，1.04-1。07]），有组织心律恢复概率降低 4%（调整后的相对风险，0.96 [95% CI，0.95-0.98]），存活至出院的概率降低 6%（调整后的相对风险，0.94 [95% CI，0.93-0.95]）。结论 首次电击每延迟一分钟，VF 终止和有组织心律恢复的比例显着降低。这可能解释了除颤长期延迟的患者的较差结果。将从紧急呼叫到第一次电击的时间间隔缩短到 ≤6 分钟可以被认为是生存链的关键绩效指标。