School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, China.
Xi'an Radio Research Institute, Xian, Shaanxi Province, China.
Am J Emerg Med. 2023 Aug;70:163-170. doi: 10.1016/j.ajem.2023.05.027. Epub 2023 May 26.
VA-ECMO can greatly reduce mortality in critically ill patients, and hypothermia attenuates the deleterious effects of ischemia-reperfusion injury. We aimed to study the effects of hypothermia on mortality and neurological outcomes in VA-ECMO patients.
A systematic search of the PubMed, Embase, Web of Science, and Cochrane Library databases was performed from the earliest available date to 31 December 2022. The primary outcome was discharge or 28-day mortality and favorable neurological outcomes in VA-ECMO patients, and the secondary outcome was bleeding risk in VA-ECMO patients. The results are presented as odds ratios (ORs) and 95% confidence intervals (CIs). Based on the heterogeneity assessed by the I statistic, meta-analyses were performed using random or fixed-effects models. GRADE methodology was used to rate the certainty in the findings.
A total of 27 articles (3782 patients) were included. Hypothermia (33-35 °C) lasting at least 24 h can significantly reduce discharge or 28-day mortality (OR, 0.45; 95% CI, 0.33-0.63; I = 41%) and significantly improve favorable neurological outcomes (OR, 2.08; 95% CI, 1.66-2.61; I = 3%) in VA-ECMO patients. Additionally, there was no risk associated with bleeding (OR, 1.15; 95% CI, 0.86-1.53; I = 12%). In our subgroup analysis according to in-hospital or out-of-hospital cardiac arrest, hypothermia reduced short-term mortality in both VA-ECMO-assisted in-hospital (OR, 0.30; 95% CI, 0.11-0.86; I = 0.0%) and out-of-hospital cardiac arrest (OR, 0.41; 95% CI, 0.25-0.69; I = 52.3%). Out-of-hospital cardiac arrest patients assisted by VA-ECMO for favorable neurological outcomes were consistent with the conclusions of this paper (OR, 2.10; 95% CI, 1.63-2.72; I = 0.5%).
Our results show that mild hypothermia (33-35 °C) lasting at least 24 h can greatly reduce short-term mortality and significantly improve favorable short-term neurologic outcomes in VA-ECMO-assisted patients without bleeding-related risks. As the grade assessment indicated that the certainty of the evidence was relatively low, hypothermia as a strategy for VA-ECMO-assisted patient care may need to be treated with caution.
VA-ECMO 可显著降低危重症患者的死亡率，而低温可减轻缺血再灌注损伤的有害影响。我们旨在研究低温对 VA-ECMO 患者死亡率和神经结局的影响。
从最早可获得的日期到 2022 年 12 月 31 日，对 PubMed、Embase、Web of Science 和 Cochrane 图书馆数据库进行了系统检索。主要结局为 VA-ECMO 患者的出院或 28 天死亡率和良好的神经结局，次要结局为 VA-ECMO 患者的出血风险。结果以比值比（OR）和 95%置信区间（CI）表示。根据 I 统计评估的异质性，使用随机或固定效应模型进行荟萃分析。使用 GRADE 方法对研究结果的确定性进行评级。
共纳入 27 篇文章（3782 例患者）。持续至少 24 小时的 33-35°C 的低温可显著降低 VA-ECMO 患者的出院或 28 天死亡率（OR，0.45；95%CI，0.33-0.63；I = 41%），并显著改善其良好的神经结局（OR，2.08；95%CI，1.66-2.61；I = 3%）。此外，低温与出血风险无关（OR，1.15；95%CI，0.86-1.53；I = 12%）。根据院内或院外心脏骤停的亚组分析，低温可降低 VA-ECMO 辅助院内（OR，0.30；95%CI，0.11-0.86；I = 0%）和院外心脏骤停（OR，0.41；95%CI，0.25-0.69；I = 52.3%）患者的短期死亡率。VA-ECMO 辅助院外心脏骤停患者的神经结局良好，与本文的结论一致（OR，2.10；95%CI，1.63-2.72；I = 0.5%）。
我们的研究结果表明，持续至少 24 小时的轻度低温（33-35°C）可显著降低 VA-ECMO 辅助治疗患者的短期死亡率，并显著改善其短期神经结局，同时无出血相关风险。由于证据等级评估表明证据的确定性相对较低，因此低温作为 VA-ECMO 辅助患者治疗的一种策略可能需要谨慎对待。
