Extracorporeal cardiopulmonary resuscitation without target temperature management for out-of-hospital cardiac arrest patients prolongs the therapeutic time window: a retrospective analysis of a nationwide multicentre observational study in Japan

Background Extracorporeal cardiopulmonary resuscitation (ECPR) with extracorporeal membrane oxygenation (ECMO) is a promising therapy for out-of-hospital cardiac arrest (OHCA) compared with conventional cardiopulmonary resuscitation (CCPR). The no and low-flow time (NLT), the interval from collapse to reperfusion to starting ECMO or to the return of spontaneous circulation (ROSC) in CCPR, is associated with the neurological outcome of OHCA. Because the effects of target temperature management (TTM) on the outcomes of ECPR are unclear, we compared the neurological outcomes of OHCA between ECPR and CCPR without TTM. Methods We performed retrospective subanalyses of the Japanese Association for Acute Medicine OHCA registry. Witnessed cases of adult cardiogenic OHCA without TTM were selected. We performed univariate, multivariable and propensity score analyses to compare the neurological outcomes after ECPR or CCPR in all eligible patients and in patients with NLT of > 30 min or > 45 min. Results We analysed 2585 cases. Propensity score analysis showed negative result in all patients (odds ratio 0.328 [95% confidence interval 0.141-0.761],P= 0.010). However, significant associated with better neurological outcome was shown in patients with NLT of > 30 min or > 45 min (odds ratio 2.977 [95% confidence interval 1.056-8.388],P= 0.039, odds ratio 5.099 [95% confidence interval 1.259-20.657],P= 0.023, respectively). Conclusion This study revealed significant differences in the neurological outcomes between ECPR and CCPR without TTM, in patients with NLT of > 30 min.