Extracorporeal cardiopulmonary resuscitation in hypothermic cardiac arrest: A secondary analysis of multicenter extracorporeal cardiopulmonary resuscitation registry data in Japan.

Aim: Extracorporeal cardiopulmonary resuscitation (ECPR) is used to resuscitate patients with cardiac arrest; however, its effect in treating hypothermic cardiac arrest has not been well studied. Therefore, in this study, we aimed to examine the characteristics and outcomes of patients with hypothermic cardiac arrest who underwent ECPR, using a multicenter out-of-hospital cardiac arrest (OHCA) registry in Japan. Methods: Baseline characteristics of patients with hypothermic OHCA and body temperature below 32 °C were assessed. Logistic regression analysis was performed to identify factors associated with in-hospital mortality and neurological outcomes in these patients. Outcomes of hypothermic and cardiogenic OHCA cases were compared using propensity-score matching to investigate differences among subgroups. Results: We included 2,157 patients, with 102 and 1,646 in the hypothermic and cardiogenic groups, respectively. Higher age and longer low-flow time were independent risk factors for mortality, and higher age was an independent risk factor for unfavorable neurological outcomes in the hypothermic OHCA group.Eighty matched pairs were selected during propensity-score matching, and the mortality rate was lower in the hypothermic group than in the cardiogenic group (46.2% vs. 77.5%; p < 0.01). Unfavorable neurological outcome rate was lower in the hypothermic group than in the cardiogenic group (62.5% vs. 87.5%; p < 0.01). Conclusions: Increased age and prolonged low-flow time were identified as negative prognostic factors in patients with hypothermic OHCA who underwent ECPR. These patients showed lower mortality and unfavorable neurological outcome rates than patients with cardiogenic OHCA, suggesting that ECPR is a promising strategy for treating hypothermic OHCA.