Resuscitation Enhancement to Avoid Rearrest Through Evidence-based Strategies in Prehospital Post-resuscitation Care

Inclusion Criteria: * Adults aged 18 years or older. * Patients with out-of-hospital cardiac arrest (OHCA) who received resuscitative care from the Siriraj Emergency Medical Services Center (SiEMS). Patients who achieved return of spontaneous circulation (ROSC) prior to hospital arrival. \- Patients subsequently transported to the Emergency Department of Siriraj Hospital for further treatment. Exclusion Criteria: * Suspected traumatic cardiac arrest. * ROSC patients whose legally authorized representative declined vasopressor administration, despite clinical indication according to the prehospital post-resuscitation care protocol. * ROSC patients who had not undergone endotracheal intubation, and whose legally authorized representative declined endotracheal intubation, despite protocol-based indication. * ROSC patients without rearrest whose legally authorized representative declined further blood investigations or additional procedures after arrival at the Emergency Department. * Patients whose legally authorized representative declined participation in the study. * Patients without an available legally authorized representative to provide consent for study participation.