Association between driving distance from nearest fire station and survival of out-of-hospital cardiac arrest

Background-Firefighter first responders dispatched in parallel with emergency medical services (EMS) personnel for out-ofhospital cardiac arrests (OHCA) can provide early defibrillation to improve survival. We examined whether survival following first responder defibrillation differed according to driving distance from nearest fire station to OHCA site. Methods and Results-From the CARES (Cardiac Arrest Registry to Enhance Survival) registry, we identified non-EMS witnessed OHCAs of presumed cardiac cause from 2010 to 2014 in Durham, Mecklenburg, and Wake counties, North Carolina. We used logistic regression to estimate the association between calculated driving distances (≤1, 1-1.5, 1.5-2, and >2 miles) and survival to hospital discharge following first responder defibrillation compared with defibrillation by EMS personnel. In total, 5020 OHCAs were included in the study. First responders more often applied the first automated external defibrillators at the shortest distances (≤1 mile) versus longest distances (>2 miles) (53.4% versus 46.6%, respectively, P<0.001). When compared with EMS defibrillation, first responder defibrillation within 1 mile and 1 to 1.5 miles of the nearest fire station was associated with increased survival to hospital discharge (odds ratio 2.01 [95% confidence interval 1.46-2.78] and odds ratio 1.61 [95% confidence interval 1.10-2.35], respectively). However, at the longest distances (1.5-2.0 and >2.0 miles), survival following first responder defibrillation did not differ from EMS defibrillation (odds ratio 0.77 [95% confidence interval 0.48-1.21] and odds ratio 0.97 [95% confidence interval 0.67-1.41], respectively). Conclusions-Shorter driving distance from nearest fire station to OHCA location was associated with improved survival following defibrillation by first responders. These results suggest that the location of first responder units should be considered when organizing prehospital systems of OHCA care.