• Survival to hospital discharge. [ Time Frame: Patients will be followed from the time of the cardiac arrest until death or hospital discharge, whichever occurs first. ] [ Designated as safety issue: No ]
  Patients may die in the field (outside of the hospital at the time of the cardiac arrest), at the emergency room, in the hospital, or they are discharged alive from the hospital. There is no average time frame for the hospitalization period as it may be less than one day or it can last 3-6 months.
  
  

• Neurologic status at discharge using modified Rankin Score and adverse events. [ Time Frame: Patients will be followed from the time of the cardiac arrest until death or hospital discharge, whichever occurs first. ] [ Designated as safety issue: Yes ]
  Patients may die in the field (outside of the hospital at the time of the cardiac arrest), at the emergency room, in the hospital, or they are discharged alive from the hospital. There is no average time frame for the hospitalization period as it may be less than one day or it can last 3-6 months.
  
  

The primary aim of the trial is to compare survival to hospital discharge after continuous chest compressions (CCC) versus standard American Heart Association (AHA) recommended cardiopulmonary resuscitation (CPR) with interrupted chest compressions (ICC) in patients with out-of-hospital cardiac arrest (OOHCA). For this study, CCC consists of a series of three cycles of continuous chest compressions without pauses for ventilation followed by rhythm analysis or until restoration of spontaneous circulation (ROSC), whichever occurs first. ICC consists of series of three cycles of standard CPR each cycle comprised of chest compressions with interposed ventilations at a compression:ventilation ratio of 30:2 (per AHA guidelines) followed by rhythm analysis or until ROSC, whichever occurs first. In either patient group, the duration of manual CPR before the first rhythm analysis will be 30 seconds or 120 seconds. This treatment period will be followed by two cycles of compressions then rhythm analysis (i.e. each of approximately 2 minutes duration) in either group. Other aims of the trial are to compare survival to discharge among patients grouped by first-recorded rhythm or other a priori subgroups, as well as to compare neurological status at discharge, mechanistic outcomes or adverse events between control and intervention groups.