Introduction: Improved out-of-hospital cardiac arrest (OHCA) outcomes are possible when cardiopulmonary resuscitation (CPR) and defibrillation are provided quickly and with an effective system of care. The only published study of OHCA in Chicago is now over 25 years old and reported a survival to hospital discharge rate of only 2%. In this study we examine temporal changes in OHCA outcomes in Chicago with implementation of systems-wide complementary initiatives.
Methods: Using raw Chicago data obtained from the Cardiac Arrest Registry to Enhance Survival (CARES), we measured temporal OHCA outcomes during implementation of multiple city initiatives including telephone-assisted and community CPR training programs, comprehensive changes in cardiac arrest care implemented by Chicago Fire Department Emergency Medical System (EMS) including high performance CPR and team based simulation training, new post resuscitation care and destination protocols, and case review for EMS providers. Hospital initiatives included implementation of therapeutic hypothermia and comprehensive outcomes tracking and reporting. Outcomes measured included rates of bystander CPR, return of spontaneous circulation (ROSC), hospital admission and survival, and favorable neurologic outcomes. Relative risk was determined by logistic regression model where observed group-specific outcomes are expressed as odds ratios (OR).
Results: Between September 1, 2013 and August 31, 2016, 6949 OHCA cases were recorded in the Chicago CARES dataset. Significantly improved outcomes (p<0.05) were observed when comparing year 1 to year 3 for bystander CPR (22.1% vs 28.3%, OR 1.39), ROSC (18.3% vs 24.7%, OR 1.46), hospital admission (22.7% vs 27.7%, OR 1.31), hospital survival (7.0% vs 8.6%, OR 1.26), and CPC 1-2 (4.2% vs 5.8%, OR 1.40).
Conclusions: Implementation of complementary initiatives at the community, prehospital, and hospital level have led to improvements in OHCA survival outcomes in Chicago. Ongoing research is focused on identifying hotspots with disparate incidence and outcomes in order to target systems-wide interventions to promote health equity.