Clinical Outcomes After Rescue Extracorporeal Cardiopulmonary Resuscitation for Out-of-hospital Cardiac Arrest

Aim: Extracorporeal cardiopulmonary resuscitation (ECPR) has been shown to have survival benefit in patients who had in-hospital cardiac arrest (IHCA). However, limited data are available on the role of extracorporeal membrane oxygenation (ECMO) for out-of-hospital cardiac arrest (OHCA). Therefore, we aimed to investigate clinical outcomes and predictors of in-hospital mortality in patients who had OHCA and who underwent ECPR.

Methods: From January 2004 to December 2013, 235 patients who received ECPR were enrolled in a retrospective, single-centre, observational registry. Among those, we studied 35 adult patients who had OHCA. The primary outcome was in-hospital mortality.

Results: Among 35 patients with a median age of 55 years (IQR 45-64), 29 (82.9%) of whom were male, ECMO implantation was successful in all and 10 patients (28.6%) lived to be discharged from the hospital. In 18 cases (51.4%), first monitored rhythms were identified as ventricular tachycardia/ventricular fibrillation, that is, shockable rhythm. There were no differences between in-hospital survivors and non-survivors regarding median time of arrest to cardiopulmonary resuscitation (CPR) (survivors: 23.5 min (IQR 18.8-27.3) vs non-survivors: 20.0 min (IQR 15.0-24.5); p=0.41) and median time of CPR to ECMO pump-on (survivors: 61.0 min (IQR 39.8-77.8) vs non-survivors 50.0 min (IQR 44.0-72.5); p=0.50). In 23 cases (65.7%), ischaemic heart disease was diagnosed and successful revascularisation was achieved in a significantly higher proportion of the survivor group (8/10 (80.0%)) than the non-survivor group (8/25 (32.0%)) (p=0.02). Witnessed arrest (HR=3.96; 95% CI 1.38 to 11.41; p=0.01), bystander CPR (HR=4.05; 95% CI 1.56 to 10.42; p=0.004) and successful revascularisation (HR=2.90; 95% CI 1.23 to 6.86; p=0.02) were independent predictors of survival-to-discharge in patients who had OHCA in univariate Cox regression analysis.

Conclusion: Survival rate for ECPR in the setting of OHCA remains poor. Our findings suggest that ECMO implantation should be very carefully considered in highly selected patients who had OHCA with little no-flow time and a reversible cause.