Hypothermia Versus Normothermia After Extracorporeal Cardiopulmonary Resuscitation for Out-of-hospital Cardiac Arrest

Inclusion Criteria: * OHCA * Age of 18-75 years, known or estimated * An initial cardiac arrest rhythm of ventricular fibrillation/pulseless ventricular tachycardia or pulseless electrical activity Exclusion Criteria: * ECMO initiated after sustained return of spontaneous circulation (ROSC) and patients with sustained ROSC before ECMO initiation * OHCA of presumed non-cardiac etiology * Time from emergency call or witnessed arrest to hospital arrival of \>60 min * Time from hospital arrival to ECMO initiation of \>60 min * Pre-hospital ECPR * Unavailability of the ECMO heat exchanger for temperature control * Glasgow Coma Scale score before temperature control of \>8 * Core body temperature upon hospital arrival of ≤32ºC * Surgical intervention before temperature control (e.g., surgical intervention for the primary disease or complications related to resuscitation/ECMO procedures) * Do Not Attempt Resuscitation) order confirmed prior to temperature control * Limitations in intensive care before temperature control * Known cerebral performance category (CPC) of 3-4 before cardiac arrest * Known chronic obstructive pulmonary disease with home oxygen therapy * Known or suspected pregnancy * Concomitant illness, such as malignancy, shortens life expectancy (180-day survival unlikely) * Consent not obtained or withdrawn by the participant or surrogate * Other reasons, physician's decision not to enroll the patient