Abstract 236: Agency Factors Associated With First Response Systems That Improve Out-of-Hospital Cardiac Arrest Outcomes

Abstract

Background: Data are conflicting regarding the association between first responder (FR) cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) with improved outcomes after out-of-hospital cardiac arrest (OHCA). Additionally, little is known about why this association varies between EMS agencies, with FR interventions being associated with better survival for only some agencies. Hypothesis: Agency characteristic differ between agencies that do a do not successfully implement FR CPR/AED for OHCA. Methods: We studied the 2016-2021 national cardiac arrest registry to enhance survival (CARES) database. We defined the exposures as FR CPR and FR AED. The outcome was survival with favorable neurologic status. We used logistic regression models to evaluate the association between FR CPR/AED and OHCA outcome for each individual agency. Based on each agency’s association between FR AED/CPR and outcomes, we stratified agencies into positive association (95% confidence interval falling entirely above 1) and no association (95% confidence below or including 1). Agencies with poor model fit were excluded. We then compared characteristics between strata. Results: For the association between FR CPR and outcomes, 21 agencies caring for 42,856 patients had a positive association; 371 agencies caring for 449,824 OHCAs had no association. For FR AED, 47 agencies caring for 103,120 OHCAs had a positive association;262 agencies caring for 327,761 OHCAs had no association. For FR CPR and compared to the no association strata, agencies with a positive association had more annual OHCAs (+300), a lower rate of FR CPR (-11.3%), and a lower rate of FR AED (-10.8%). For FR AED and compared to the no association strata, agencies with a positive association FR AED and outcomes had more OHCAs per year (+150.5), a lower rate of FR CPR (-6.8%), a lower rate of FR AED (-13.3%), lower response times (-0.6 minutes), and more OHCAs from high-income neighborhoods (+3.7%). Conclusion: More agencies had a positive association between FR AED and survival with favorable neurologic outcome than between FR CPR and survival with favorable neurologic outcome. Agencies with better outcomes from FR interventions treated more OHCAs and had lower rates of FR intervention.