 Through collaboration of clinicians from all areas and with BCEHS, this study will examine the benefit of a regional ECPR protocol established in one of the metropolitan areas the ECPR Protocol Region, in comparison to the other areas the Usual Care Region. The primary aim is to determine the benefit of incorporating ECPR services into a regional medical system of care for out-of-hospital cardiac arrest. All patients with out-of-hospital cardiac arrest treated by emergency medical services EMS in both regions will be prospectively evaluated for study eligibility. 