Abstract 86: AED Allocation: Creating Rules for AED Placement Based on Urban Risk Maps

Abstract

Background: Although the prompt use of automatic external defibrillators (AEDs) in out of hospital cardiac arrest (OHCA) can be lifesaving, policies to guide placement of publicly accessible AEDs are not clearly defined. Objectives: To use location-based risk, location density, and presence of a designated responder to create a risk-based mapping framework to guide urban AED placement. Methods: Literature reporting frequency of OHCA by location type in urban areas was used to create a list of candidate sites in downtown Philadelphia, PA. Location-based risk areas were plotted using ArcGIS with a kernel density surface that reflected walking time of approximately 1.5 minutes. Locations were identified through available public records and the Google search engine. Designated responder status was assigned by location type. Sites were weighted by risk of arrest and multiplied by density of designated responders to create a composite “opportunity” layer. Hypothetical sites for 20 new AEDs were then mapped by selecting the point with the highest opportunity score, “placing” an AED, and recalculating opportunity scores for the entire study area. This process was iterated until 20 hypothetical AEDs were sited. Results: Thirty types of locations with previously-studied frequency of OHCA were identified. Figure 1 identifies several high-risk areas for OHCAs with AED caretakers present to use devices in an emergency that could benefit from close proximity to an AED. Conclusions: A location-based risk map for OHCA identifies specific higher-risk locations to locate AEDs in an urban area. The metrics to build this theoretical framework for device allocation can be used by cities to guide more strategic AED placement based on their unique cardiac arrest data and current AED placement. Figure 1: