Cohort study on the factors associated with survival post-cardiac arrest

CONTEXT AND OBJECTIVE: Cardiac arrest is a common occurrence, and even with efficient emergency treatment, it is associated with a poor prognosis. Identification of predictors of survival after cardiopulmonary resuscitation may provide important information for the healthcare team and family. The aim of this study was to identify factors associated with the survival of patients treated for cardiac arrest, after a one-year follow-up period. DESIGN AND SETTING: Prospective cohort study conducted in the emergency department of a Brazilian university hospital. METHODS: The inclusion criterion was that the patients presented cardiac arrest that was treated in the emergency department (n = 285). Data were collected using the In-hospital Utstein Style template. Cox regression was used to determine which variables were associated with the survival rate (with 95% significance level). RESULTS: After one year, the survival rate was low. Among the patients treated, 39.6% experienced a return of spontaneous circulation; 18.6% survived for 24 hours and of these, 5.6% were discharged and 4.5% were alive after one year of follow-up. Patients with pulseless electrical activity were half as likely to survive as patients with ventricular fibrillation. For patients with asystole, the survival rate was 3.5 times lower than that of patients with pulseless electrical activity. CONCLUSIONS: The initial cardiac rhythm was the best predictor of patient survival. Compared with ventricular fibrillation, pulseless electrical activity was associated with shorter survival times. In turn, compared with pulseless electrical activity, asystole was associated with an even lower survival rate.

研究背景与研究目的：心脏骤停（Cardiac Arrest）是一种常见急症，即便接受高效的急诊救治，其预后仍较差。识别心肺复苏（Cardiopulmonary Resuscitation）后患者的生存预测因子，可为医疗团队及患者家属提供重要参考信息。本研究旨在明确接受治疗的心脏骤停患者经1年随访期后的生存相关影响因素。
研究设计与研究地点：本研究为前瞻性队列研究，于巴西某大学医院急诊科开展。
研究方法：纳入标准为在急诊科接受治疗的心脏骤停患者（共285例）。数据采用院内Utstein模式模板（In-hospital Utstein Style template）进行采集。采用Cox回归（Cox regression）分析确定与生存率相关的变量，显著性水平设定为95%。
研究结果：随访1年后总体生存率较低。纳入的治疗患者中，39.6%实现了自主循环恢复（Return of Spontaneous Circulation, ROSC）；18.6%存活至24小时，其中5.6%的患者出院，4.5%的患者在随访1年后仍存活。无脉电活动（Pulseless Electrical Activity, PEA）患者的生存概率仅为心室颤动（Ventricular Fibrillation, VF）患者的一半。心搏停止（Asystole）患者的生存率较无脉电活动患者低3.5倍。
研究结论：初始心脏节律是患者生存的最佳预测因子。与心室颤动相比，无脉电活动与更短的生存时长相关；而与无脉电活动相比，心搏停止的生存率更低。