Strategic Automated External Defibrillator Deployment Based on Geospatial Analysis of Historical Cardiac Arrest Locations

Abstract Objective We hypothesized that historical out-of-hospital sudden cardiac arrest (SCA) event locations can inform deployment of automated external defibrillators (AEDs). Methods Consecutive SCA events attended by EMS were ascertained prospectively in two identically designed community-based studies in California (Ventura County, SCA n=2,935) and Oregon (Multnomah County, SCA n=2,213). Clusters of ≥3 historical SCA events within a 100-meter radius were plotted using geospatial analysis. Proposed AED locations were positioned within 200-meters of the clusters. An existing AED registry in Ventura County (n=998) with coordinates was also plotted. Distances between SCAs and proposed AEDs were calculated. Results In Ventura County, 97 clusters of ≥3 SCAs were identified, covering 22% (n=653) of total SCAs with 90 proposed AEDs assigned to the clusters. The mean distance between individual SCA events and the nearest AED was 99.7 (SD=53.1) meters, representing a bystander AED response time of 3.0 (SD=1.6) minutes. Proposed bystander AED response times were significantly shorter than actual EMS response times [mean difference: 3.1 (95% CI: 2.9-3.4), p<0.0001]. Similar results were observed in Multnomah County. Compared to the existing AED registry in Ventura County, 18.9% (n=17) of our 90 proposed AEDs were within 200 meters of an existing AED. Of total SCAs in Ventura County,11.4% (n=334) were within 200 meters of an existing AED. Conclusions 16-22% of historical SCA events could potentially be covered by 78-90 AEDs. The remainder could be served by utilizing the standard EMS response. Outcomes studies that compare this geospatial event-localization strategy to current AED location strategies are warranted. Data Sharing statement The entire deidentified dataset, data dictionary and analytic code for this investigation are available upon request, from the date of article publication by contacting Sumeet S. Chugh, MD, at sumeet.chugh@cshs.org .