Prevalence, natural history, and time-dependent outcomes of a multi-center North American cohort of out-of-hospital cardiac arrest extracorporeal CPR candidates

Aim: Estimate prevalence of ECPR-eligible subjects in a large, North American, multi-center cohort, describe natural history with conventional resuscitation, and predict optimal timing of transition to ECPR.

Methods: Secondary analysis of clinical trial enrolling adults with non-traumatic OHCA. Primary outcome was survival to discharge with favorable outcome (mRS 0-3). Subjects were additionally classified as survival with unfavorable outcome (mRS 4-5), ROSC without survival (mRS 6), or without ROSC. We plotted subject accrual as a function of resuscitation duration (CPR onset to return of spontaneous circulation (ROSC) or termination of resuscitation), and estimated time-dependent probabilities of ROSC and mRS 0-3 at discharge. Adjusted logistic regression models tested the association between resuscitation duration and survival with mRS 0-3.

Results: Of 11,368 subjects, 1237 (10.9%; 95%CI 10.3-11.5%) were eligible for ECPR, Of these, 778 (63%) achieved ROSC, 466 (38%) survived to discharge, and 377 (30%) had mRS 0-3 at discharge. Half with eventual mRS 0-3 achieved ROSC within 8.8min (95%CI 8.3-9.2min) of resuscitation, and 90% within 21.0min (95%CI 19.1-23.7min). Time-dependent probabilities of ROSC and mRS 0-3 declined over elapsed resuscitation, and the likelihood of additional cases with mRS 0-3 beyond 20min was 8.4% (95%CI 5.9-11.0%). Resuscitation duration was independently associated with survival to discharge with mRS 0-3 (OR 0.95; 95%CI 0.92-0.97).

Conclusion: Approximately 11% of subjects were eligible for ECPR. Only one-third survived to discharge with favorable outcome. Performing 9-21min of conventional resuscitation captured most ECPR-eligible subjects with eventual mRS 0-3 at hospital discharge.