Association Between Driving Distance From Nearest Fire Station and Survival of Out-of-Hospital Cardiac Arrest

Abstract

Background Firefighter first responders dispatched in parallel with emergency medical services ( EMS ) personnel for out-of-hospital 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 OHCA s 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 OHCA s 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.

Keywords: driving distance; early defibrillation; firefighter; first responder; out‐of‐hospital cardiac arrest.

Figure 1

Flowchart showing the out‐of‐hospital cardiac arrest study population. EMS indicates emergency medical service; OHCA, out‐of‐hospital cardiac arrest.

Figure 2

Survival and favorable neurological outcome according to distance to nearest fire station. Odds ratios of survival to discharge after out‐of‐hospital cardiac arrest for patients defibrillated by first responders within 1 mile, 1 to 1.5 miles, 1.5 to 2 miles, and >2 miles, and patients not defibrillated compared with defibrillation by emergency medical services personnel (reference). A, Associations for survival to hospital discharge. B, Associations for a favorable neurological outcome for both unadjusted and adjusted logistic regression analyses. *Adjusted for age, sex, layperson CPR, location of arrest, witnessed arrest status, year of arrest, and neighborhood characteristics (unemployment rate, poverty rate, and percentage of white or other races). CI indicates confidence interval; CPR, cardiopulmonary resuscitation; EMS, emergency medical services; OR, odds ratio.

Figure 3

Survival to hospital discharge and favorable neurological outcome following first responder or EMS defibrillation at different driving distances from fire stations to OHCA sites. A, Survival to hospital discharge following first responder defibrillation (n=776) or EMS defibrillation (n=725) at different driving distances from nearest fire station. B, Survival with a favorable neurological outcome following first responder defibrillation (n=776) or EMS defibrillation (n=725) at different driving distances from nearest fire station. Logistic regression with restricted cubic splines (knots at 1, 1.5, and 2 miles) was used to make the models. EMS, emergency medical services; OHCA, out‐of‐hospital cardiac arrest.

Figure 4

Overall out‐of‐hospital cardiac arrest survival to hospital discharge at different driving distances from fire stations to OHCA sites. Overall survival for all OHCA patients (n=5020) to hospital discharge according to driving distance from nearest fire station to the OHCA site. Logistic regression with restricted cubic splines (knots at 1, 1.5, and 2 miles) was used to make the model. OHCA indicates out‐of‐hospital cardiac arrest.