Survival and neurological outcome in patients treated with extracorporeal membrane oxygenation and therapeutic hypothermia: an updated systematic review and meta-analysis

Why clinicians should know about it

• Picked for Cardiology and Cardiovascular Medicine (top studies of the week, 26 July 2026): Meta‑analysis of ECMO + therapeutic hypothermia after cardiac arrest
• Picked for Emergency Medicine (top studies of the week, 26 July 2026).
• Picked for Epidemiology (top studies of the week, 26 July 2026).

Abstract

OBJECTIVE: To assess the impact of therapeutic hypothermia on survival, neurological outcome, and complications in adult patients with cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation (ECPR). METHODS: A systematic search of PubMed, Embase, Web of Science, the Cochrane Library, and major Chinese databases was conducted from their inception to March 31, 2026. Randomized controlled trials (RCTs) and non-randomized studies of interventions comparing therapeutic hypothermia with normothermia or fever prevention alone in adult patients undergoing ECPR were included. The primary outcomes were survival and favorable neurological outcome. The secondary outcome was the incidence of complications. A random-effects model was used to calculate pooled risk ratios (RRs) and their 95% confidence intervals (CIs), with results stratified by study design. RESULTS: A total of 31 studies involving 6,184 ECPR patients were included, of which only 3 were RCTs. Pooled randomized trials did not demonstrate a significant benefit of therapeutic hypothermia for either survival to hospital discharge (RR = 1.30, 95% CI: 0.70-2.40, P = 0.41) or favorable neurological outcome at discharge (RR = 1.80, 95% CI: 0.86-3.77, P = 0.12), and no benefit was demonstrated at 1, 3, or 6 months. In contrast, observational studies showed that therapeutic hypothermia was associated with better survival (RR = 1.41, 95% CI: 1.14-1.74, P = 0.002) and more favorable neurological outcomes (RR = 1.61, 95% CI: 1.21-2.14, P = 0.001), though these were based on crude, unadjusted data with substantial heterogeneity. Among these observational studies, the associations appeared confined to a moderate target temperature (32.0-34.0°°C; survival RR = 1.73; neurological RR = 2.27), with no significant association at mild temperatures (34.0-36.0 °C). Therapeutic hypothermia was not associated with an increased risk of major complications in ECPR patients. CONCLUSIONS: Pooled randomized evidence did not demonstrate better survival or more favorable neurological outcomes with therapeutic hypothermia in ECPR patients; more favorable outcomes were confined to crude observational data at high risk of bias. With certainty of evidence rated low to very low, adequately powered randomized trials are needed before firm conclusions can be drawn. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/, identifier CRD42023435353.

Abstract as published, via PubMed.