Selection of patients for mechanical circulatory support for refractory out-of-hospital cardiac arrest: a Danish nationwide multicenter study

Abstract Background Extracorporeal cardiopulmonary resuscitation (ECPR) is a potential salvage therapy for selected patients with refractory out-of-hospital cardiac arrest (OHCA). Purpose The objective of this study was to describe the characteristics of potential ECPR patients. Methods This retrospective, observational cohort study included 579 patients admitted with refractory OHCA for possible ECPR at all tertiary cardiac arrest centers in Denmark between 2015 and 2020. Presenting characteristics, reasons for refraining from ECPR, and survival to hospital discharge were recorded. Results After initial evaluation, 221 patients (38%) proceeded to ECPR, and 358 (62%) were considered futile. Median prehospital low-flow time was 70 minutes [interquartile range 56–85] in ECPR patients and 62 minutes [48–81] in no-ECPR patients, p<0.001. Intra arrest transport was more than 50 km in 92 (42%) ECPR patients and 135 in no-ECPR patients (38%), p=0.25. Treatment decision was taken by a team of three specialists in 513 cases (97%). The leading cause for not initiating ECPR was duration of low flow time (39%). Severe metabolic derangement and low end-tidal CO2 (ETCO2) were contributing factors in 35% and 31%, respectively, Figure 1. 83% of the patients had two or more contributing factors recorded as reasons for not initiating ECPR, Figure 2. The most prevailing combination of contributing factors were non-shockable rhythm, low ETCO2, and metabolic derangement or duration of prehospital low flow time combined with low ETCO2. Survival to discharge was achieved in six patients (1.7%) in the no-ECPR group and 50 (23%) in the ECPR group. Conclusions In this large nationwide study of patients admitted for possible ECPR, 62% were not treated with ECPR. The most frequent reasons to abstain from ECPR were duration of prehospital low flow time, metabolic derangement, and low ETCO2. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation