Fibrinogen levels and bleeding risk in adult extracorporeal cardiopulmonary resuscitation: multicenter observational study subanalysis.

•Hypofibrinogenemia frequently occurs in extracorporeal cardiopulmonary resuscitation (ECPR) and may heighten bleeding risk. This subanalysis of a multicenter observational study (SAVE-J II) included 2,100 adult patients receiving ECPR after out-of-hospital cardiac arrest at 36 facilities in Japan.•Overall, 7.5% of patients experienced non-cannulation hemorrhagic complications, and those with fibrinogen levels below 140 mg/dL at ECPR initiation faced significantly higher bleeding risk. These findings underscore the importance of monitoring and managing fibrinogen levels in ECPR to mitigate hemorrhagic events and improve patient outcomes.