b"Early CPROne of the critical interventions for successful resuscitation is early CPR. Starting CPR before the arrival of an ambulance significantly increases a patient's chances of survival. In 2023, bystander CPR was initiated on 41.2% of CARES patients. Of note, CARES excludes events witnessed by 911 Responders as well as those that occurred in a nursing home or healthcare facility from our bystander CPR rate, as CPR in these scenarios is typically performed by trained medical providers.Bystander CPR provision was strongly correlated with arrest witness status (Figure 13). Bystander CPR was initiated after 49.7% of bystander witnessed events, compared to 34.8% of unwitnessed events (p.0001).70% 65.2%60%50% 49.7% 50.3%40% 34.8%30%20%10%0%Bystander Witnessed UnwitnessedBystander CPR No Bystander CPRFigure 13. Bystander CPR provision by arrest witness status.Return of spontaneous circulation (ROSC) in the field, survival to hospital admission, and survival to hospital discharge were all strongly associated with receipt of bystander CPR (Figure 14). The survival to discharge rate for patients receiving bystander CPR (12.5%) was significantly higher (p.0001) than that of patients who did not receive bystander CPR (7.6%).30% 29.2% 28.5%23.9% 22.7%20%12.5%10% 7.6%0%Bystander CPR No Bystander CPRSustained ROSC Survived to admission Survived to dischargeFigure 14. Unadjusted survival outcomes after bystander CPR.36 37"