This study examines the incidence and predictors of bleeding and thrombosis in patients treated with extracorporeal cardiopulmonary resuscitation (ECPR) after out-of-hospital cardiac arrest due to ventricular tachycardia/fibrillation. Among 200 patients, 67.5% experienced major bleeding, primarily from CPR-related trauma. Decreased fibrinogen levels were linked to bleeding, but bleeding did not significantly affect in-hospital mortality. Thrombosis occurred in 23.5% of patients and was not associated with in-hospital death.