ECMO-facilitated resuscitation may improve survival compared to ACLS in patients with out-of-hospital cardiac arrests

1. Survival to hospital discharge was higher among patients in the ECMO-facilitated resuscitation group versus those receiving ACLS resuscitation.

2. Patients who received early ECMO had significantly higher survival at 3 and 6 months compared to the ACLS group.

Evidence Rating Level: 2 (Good)

Study Rundown: Out-of-hospital cardiac arrest (OHCA) accounts for a large number of cardiac mortalities in North America. Among patients with OHCA and ventricular fibrillation, nearly half present with refractory ventricular fibrillation that is unresponsive to advanced cardiac life support (ACLS). This single centre, open-label, randomized controlled trial aimed to compare survival to hospital discharge between patients treated with ACLS and extracorporeal membrane oxygenation (ECMO)-facilitated resuscitation. Primary outcome for this study was survival to hospital discharge, while secondary endpoints included cumulative survival and functionally favourable status at hospital discharge, and at 3 and 6 months after discharge.

Study results demonstrated a significant increase in survival to discharge among patients in the ECMO group compared to the ACLS group. In addition, cumulative survival was significantly better with early ECMO than with standard ACLS treatment. However, many patients in the early ECMO group reported hospitalization-related reduced functional assessment at discharge. This randomized controlled trial was limited by a small sample size since only 29 patients – all from a single medical centre – were included in the analysis. Nonetheless, this study is the first to show that ECMO-facilitated resuscitation improves survival in patients presenting with OHCA and refractory ventricular fibrillation versus standard ACLS.

Click to read the study in The Lancet

Relevant Reading: Extracorporeal Cardiopulmonary Resuscitation (ECPR) for Out-of-Hospital Cardiac Arrest due to Pulseless Ventricular Tachycardia/Fibrillation

In-depth [randomized controlled trial]: Between Aug 8, 2019, and Jun 14, 2020, 36 patients were assessed for eligibility at the University of Minnesota Medical Center (USA). Included patients were those between 18-75 years of age with OHCA and refractory ventricular fibrillation, no return of spontaneous circulation (ROSC) after three shocks, automated cardiopulmonary resuscitation, and estimated transfer time to catheterization laboratory <30 minutes. Patients with initial pulseless electrical activity (PEA), transfer time > 30 minutes, and ROSC with second shock were excluded. Altogether, 30 patients were enrolled in the study and 29 patients (14 in the ECMO group and 15 in the ACLS group) were included in the analysis. Baselines characteristics were similar between the study groups.

Among enrolled patients, the mean age was 59 years (standard deviation [SD] 10, range 36-73) and 83% were male. The primary outcome of survival to hospital discharge was observed among 6 patients (43%, 95% credible interval 21.3-67.7) in the early ECMO group compared to 1 patient (7%, 95% CI 1.6-30.2) in the standard ACLS group (risk difference 36%, 95% credible interval 3.7-59.2, posterior probability of ECMO superiority 0.9861). Survival at 3 and 6 months was significantly improved in the early ECMO group (6 out of 14 patients at 3 and 6 months) compared to that in the standard ACLS group (none at 3 and 6 months, p=0.0063). The secondary outcome of cumulative survival was significantly better with early ECMO than with standard ACLS treatment (hazard ratio [HR] 0.16, 95% confidence interval [CI] 0.06-0.41, log-rank test p<0.0001). In the early ECMO group, 2 patients met the resuscitation discontinuation criteria and died prior to treatment whereas 13 patients in the standard ACLS group died due to unsuccessful resuscitation. Findings from this study suggest that early ECMO-facilitated resuscitation significantly improved survival to hospital discharge for patients with OHCA and refractory ventricular fibrillation compared to standard ACLS resuscitation.

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