Extracorporeal cardiopulmonary resuscitation for adults with shock‐refractory cardiac arrest

BACKGROUND: Veno‐arterial extracorporeal membrane oxygenation has increasingly emerged as a feasible treatment to mitigate the progressive multiorgan dysfunction that occurs during cardiac arrest, in support of further resuscitation efforts. OBJECTIVES: Because the recent systematic review commissioned in 2018 by the International Liaison Committee on Resuscitation Advanced Life Support task did not include studies without a control group, our objective was to conduct a review incorporating these studies to increase available evidence supporting the use of extracorporeal cardiopulmonary resuscitation (ECPR) for cardiac arrest patients, while waiting for high‐quality evidence from randomized controlled trials (RCTs). METHODS: MEDLINE, Embase, and Science Citation Index (Web of Science) were searched for eligible studies from database inception to July 20, 2020. The population of interest was adult patients who had suffered cardiac arrest in any setting. We included all cohort studies with 1 exposure/1 group and descriptive studies (ie, case series studies). We excluded RCTs, non‐RCTs, and observational analytic studies with a control group. Outcomes included short‐term survival and favorable neurological outcome. Short‐term outcomes (ie, hospital discharge, 30 days, and 1 month) were combined into a single category. RESULTS: Our searches of databases and other sources yielded a total of 4302 citations. Sixty‐two eligible studies were included (including a combined total of 3638 participants). Six studies were of in‐hospital cardiac arrest, 34 studies were of out‐of‐hospital cardiac arrest, and 22 studies included both in‐hospital and out‐of‐hospital cardiac arrest. Seven hundred and sixty‐eight patients of 3352 (23%) had short‐term survival; whereas, 602 of 3366 (18%) survived with favorable neurological outcome, defined as a cerebral performance category score of 1 or 2. CONCLUSIONS: Current clinical evidence is mostly drawn from observational studies, with their potential for confounding selection bias. Although studies without controls cannot supplant case‐control or cohort studies, several ECPR studies without a control group show successful resuscitation with impressive results that may provide valuable information to inform a comparison.