Faculty of Medicine, Department of Family Medicine and Emergency Medicine, Université de Montréal, Montréal, QC, Canada.
Centre de Recherche de l'Hôpital du Sacré-Cœur de Montréal, Montréal, QC, Canada.
Crit Care Med. 2022 Oct 1;50(10):1494-1502. doi: 10.1097/CCM.0000000000005594. Epub 2022 Jun 8.
The no-flow time (NFT) can help establish prognosis in out-of-hospital cardiac arrest (OHCA) patients. It is often used as a selection criterion for extracorporeal resuscitation. In patients with an unwitnessed OHCA for whom the NFT is unknown, the initial rhythm has been proposed to identify those more likely to have had a short NFT. Our objective was to determine the predictive accuracy of an initial shockable rhythm for an NFT of 5 minutes or less (NFT ≤ 5).
Retrospective analysis of prospectively collected data.
Prehospital OHCA in eight U.S. and three Canadian sites.
A total of 28,139 adult patients with a witnessed nontraumatic OHCA were included, of whom 11,228 (39.9%) experienced an emergency medical service-witnessed OHCA (NFT = 0), 695 (2.7%) had a bystander-witnessed OHCA, and an NFT less than or equal to 5, and 16,216 (57.6%) with a bystander-witnessed OHCA and an NFT greater than 5.
Sensitivity, specificity, and likelihood ratios of an initial shockable rhythm to identify patients with an NFT less than or equal to 5 minutes.
The sensitivity of an initial shockable rhythm to identify patients with an NFT less than or equal to 5 was poor (25% [95% CI, 25-26]), but specificity was moderate (70% [95% CI, 69-71]). The positive and likelihood ratios were inverted (negative accuracy) (positive likelihood ratio, 0.76 [95% CI, 0.74-0.79]; negative likelihood ratio, 1.12 [95% CI, 1.10-1.12]). Including only patients with a bystander-witnessed OHCA improved the sensitivity to 48% (95% CI, 45-52), the positive likelihood ratio to 1.45 (95% CI, 1.33-1.58), and the negative likelihood ratio to 0.77 (95% CI, 0.72-0.83), while slightly lowering the specificity to 67% (95% CI, 66-67).
Our analysis demonstrated that the presence of a shockable rhythm at the time of initial assessment was poorly sensitive and only moderately specific for OHCA patients with a short NFT. The initial rhythm, therefore, should not be used as a surrogate for NFT in clinical decision-making.
无血流时间 (NFT) 可帮助确定院外心脏骤停 (OHCA) 患者的预后。它常被用作体外复苏的选择标准。对于 NFT 未知的未经目击的 OHCA 患者，初始节律已被提出用于识别那些 NFT 较短的可能性更大的患者。我们的目的是确定初始可电击节律对 NFT 为 5 分钟或更短（NFT ≤ 5）的预测准确性。
前瞻性收集数据的回顾性分析。
美国和加拿大的 8 个和 3 个地点的院前 OHCA。
共纳入 28139 名成年目击非创伤性 OHCA 患者，其中 11228 名（39.9%）经历了急救人员目击的 OHCA（NFT = 0），695 名（2.7%）经历了旁观者目击的 OHCA 和 NFT 小于或等于 5，16216 名（57.6%）经历了旁观者目击的 OHCA 和 NFT 大于 5。
初始可电击节律识别 NFT 小于或等于 5 分钟的患者的敏感性、特异性和似然比。
初始可电击节律识别 NFT 小于或等于 5 分钟的患者的敏感性较差（25% [95%CI，25-26%]），但特异性中等（70% [95%CI，69-71%]）。阳性和似然比是颠倒的（阴性准确性）（阳性似然比，0.76 [95%CI，0.74-0.79]；阴性似然比，1.12 [95%CI，1.10-1.12]）。仅包括旁观者目击的 OHCA 患者可将敏感性提高到 48%（95%CI，45-52），阳性似然比提高到 1.45（95%CI，1.33-1.58），阴性似然比提高到 0.77（95%CI，0.72-0.83），同时特异性略有下降至 67%（95%CI，66-67）。
我们的分析表明，初始评估时存在可电击节律对 NFT 较短的 OHCA 患者的敏感性较差，特异性仅中等。因此，初始节律不应在临床决策中用作 NFT 的替代指标。
