Eligibility for Extracorporeal Cardio-Pulmonary Resuscitation in Out-of-Hospital Cardiac Arrests in Sweden

Extracorporeal Cardio-Pulmonary Resuscitation (ECPR) can potentially enhance outcomes following out-of-hospital cardiac arrest (OHCA). Selection criteria determine candidacy for ECPR and affect outcomes, as do numbers of ECPR treatments per centre. The objective of this study was to evaluate ECPR eligibility amongst witnessed OHCA in Sweden, by means of the Swedish Registry for Cardiopulmonary Resuscitation.

Data of witnessed OHCA was extracted from the registry between Jan 2015 and Aug 2019. Evaluation of ECPR-candidacy was based on selection criteria and transport time. Treatment was considered contraindicated if no-flow time extended beyond 5 min. Two groups were defined: Group Restrictive (GR); 18-65 years of age with shockable rhythm and Group Liberal (GL); 18-70 years of age, independent of rhythm. Emergency medical services stations of corresponding OHCA was plotted on a map and time of transportation calculated. Maximum time for transportation was set to 40 min.

Out of 15,911 witnessed OHCA, 6372 were considered ECPR-ineligible due to extended no-flow time. GR constituted of 1519 and GL 5851 OHCA. Cases with return of spontaneous circulation at admission were subtracted from both groups. The remaining OHCA in GR (636) and GL (3558) were considered ECPR-candidates. After excluding cases due to extended time of transport, 218 and 1246 candidates remained ECPR-eligible in GR and GL respectively.

The quantity of ECPR-eligible patients amongst OHCA is highly dependent on selection criteria and geographics. In Sweden, we estimate an annual incidence of 46-267 potential candidates per 10.5 M inhabitants, corresponding to 1.4%-7.8% of all witnessed OHCA.

This analysis of the national database for out of hospital cardiac arrest in Sweden from a selected period uses case characteristics to estimate how many might be eligible for extra-corporeal cardiopulmonary resuscitation given today's criterial for this type of treatment.