Eligibility of extracorporeal cardiopulmonary resuscitation on in-hospital cardiac arrests in Sweden: a national registry study

Aims: Extracorporeal cardiopulmonary resuscitation (ECPR) for refractory cardiac arrest (CA) is used in selected cases. The incidence of ECPR-eligible patients is not known. The aim of this study was to identify the ECPR-eligible patients among in-hospital CAs (IHCA) in Sweden and to estimate the potential gain in survival and neurological outcome, if ECPR was to be used.

Methods and results: Data between 1 January 2015 and 30 August 2019 were extracted from the Swedish Cardiac Arrest Register (SCAR). Two arbitrary groups were defined, based on restrictive or liberal inclusion criteria. In both groups, logistic regression was used to determine survival and cerebral performance category (CPC) for conventional cardiopulmonary resuscitation (cCPR). When ECPR was assumed to be possible, it was considered equivalent to return of spontaneous circulation, and the previous logistic regression model was applied to define outcome for comparison of conventional CPR and ECPR. The assumption in the model was a minimum of 15 min of refractory CA and 5 min of cannulation. A total of 9209 witnessed IHCA was extracted from SCAR. Depending on strictness of inclusion, an average of 32-64 patients/year remains in refractory after 20 min of cCPR, theoretically eligible for ECPR. If optimal conditions for ECPR are assumed and potential negative side effects disregarded of, the estimated potential benefit of survival of ECPR in Sweden would be 10-19 (0.09-0.19/100 000) patients/year, when a 30% success rate is expected. The benefit of ECPR on survival and CPC scoring was found to be detrimental over time and minimal at 60 min of cCPR.

Conclusion: The number of ECPR-eligible patients among IHCA in Sweden is dependent on selection criteria and predicted to be low. There is an estimated potential benefit of ECPR, on survival and neurological outcome if initiated within 60 min of the IHCA.