The Effect of Prehospital Combination of Epinephrine, Vasopressin, and Steroid in OHCA

Inclusion Criteria: * Adult patients (aged \>= 18 ) * Out-of-hospital cardiac arrest in the studied regions * Treated by paramedics authorized and capable of giving prehospital medication Exclusion Criteria: * OHCA with traumatic etiology * Obvious signs of death like decapitation, rigor mortis, livor mortis, decomposition, etc. * DNR (Do Not Resuscitation) or termination of resuscitation requested by the family * Patients with known or suspected pregnancy * No vascular access was established before hospital arrival * ROSC before the administrated medication * No patient contact (cancelled ambulance call or the patient was transported to the hospital before the arrival of trial-trained paramedics) * Received epinephrine prior to the arrival of trial-trained paramedics