24 Early CPR One of the critical interventions to achieving successful resuscitation is early CPR. If CPR is started before an ambulance arrives, the patient’s chances of survival dramatically increase. In 2017, bystander CPR was initiated on 38.2% of CARES patients. Of note, CARES excludes 911 Responder witnessed events as well as those that occurred in a nursing home or healthcare facility from our bystander CPR rate, as these are scenarios where we would expect CPR to be performed by a trained medical provider. Bystander CPR provision was strongly correlated with arrest witness status (Figure 13). Bystander CPR was initiated after 46.9% of bystander witnessed events, compared with 31.7% of unwitnessed events (p