Abstract 22: Geographic Proximity of Automated External Defibrillators to Out-of-hospital Sudden Deaths in Wake County, North Carolina

Abstract

Introduction: Survival rates for out-of-hospital sudden cardiac arrest are substantially improved by access to automated external defibrillators (AEDs) prior to Emergency Medical Services (EMS) arrival. However, AED use may be inhibited if their locations are unknown or far from the bystander. Objectives: We sought to classify out-of-hospital sudden death (OHSD) event locations, ascertain if bystanders utilized AEDs prior to EMS arrival, and calculate the distance to the nearest AED. Methods: From 2013 to 2015, we screened all EMS-reported out-of-hospital deaths aged 18-64 within Wake County, North Carolina to identify OHSDs. We geocoded event locations from EMS records and classified them as residential, commercial, public, or unknown using US Postal Service Residential Delivery Indicator, EMS narratives, and web searches. AED locations and installation dates, registered by law, were obtained from North Carolina Department of Health and Human Services. We used EMS narratives to determine AED use prior to EMS arrival. Walking distance between coordinates of an OHSD location and every AED installed prior to the death date was estimated using the Great-Circle distance. Results: Of 434 adjudicated OHSDs, 390 (90%) were residential, 31 (7%) were commercial, and 11 (2.5%) were public. Of commercial locations, 12 (39%) occurred in hotels. Of public locations, 6(46%) occurred in parking lots or parks. Wake County had 168 registered AEDs during the study period. The mean distance from OHSD to closest AED was 3.2 km (95% CI: 3.0-3.5 km). Only 20 (4.6%) of OHSDs were within 500 meters of an AED; the closest AED was 77 meters from an OHSD. Bystanders used AEDs prior to EMS arrival twice. Conclusions: While potentially lifesaving, AEDs are not placed optimally with respect to OHSD locations and are rarely utilized by bystanders, even in non-residential spaces. Public health strategies should be considered that incentivize optimal AED placement to witnessed cardiac arrest locations.