Introduction: The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in extracorporeal cardiopulmonary resuscitation (eCPR) in selected patients (pts) after out of hospital cardiac arrest (OHCA) is an established method if return of spontaneous circulation cannot be achieved. Mechanical CPR (mCPR) devices facilitate transportation of pts under ongoing CPR and might thus improve outcome. We sought to evaluate prognostic influence of mCPR and a variety of other parameters in pts presenting with OHCA treated with eCPR including VA-ECMO.

Methods: We retrospectively analysed data of 152 consecutive pts treated for OHCA using eCPR in our cardiac arrest center from the years 2008 to 2020. A survival regression model was used to identify favourable characteristics.

Results: Of the 152 analysed pts (84% male, mean age 58 years) 19% (29) survived the initial hospitalization with favourable neurological outcome. Primary reason for OHCA was an acute coronary event (72%) followed by primary arrhythmia (10%) and cardiogenic shock (6.8%). In most cases, the collapse was witnessed (83%) and bystander CPR was performed (86%). The mean time from collapse to VA-ECMO was 84 min (±32 min). Multivariable analysis showed that the use of a mechanical CPR device (HR: 0.53 [95%CI: 0.34 – 0.83]), as well as a coronary event as primary reason for OHCA (HR: 0.58 [95%CI: 0.35 – 0.96]) were favourable for overall survival. Known atrial fibrillation prior to OHCA was also associated with a higher probability of survival (HR: 0.4 [95%CI: 0.23 – 0.7]). Pts in whom mCPR was performed presented with overall longer times from collapse to ECMO than those who were resuscitated manually (85 min; 95%CI: 74 – 102 min vs. 68 min; 95%CI: 57 – 84 min).

Conclusion: Our analysis suggests a significant survival benefit for the use of mCPR devices before eCPR is established, despite longer time from collapse to ECMO, likely due to the limited availability of mCPR devices in pre-clinical paramedic service at the time of observation. Increasing availability of these devices might thus improve treatment of OHCA, presumably by providing more efficient CPR during transportation and transfer. Interestingly we found that known atrial fibrillation was associated with a beneficial outcome. This might be explained by prior anticoagulation therapy and thus less thrombotic mass in cases of acute coronary events, which were the most common cause of OHCA in the studied collective.