Optimization of automated external defibrillator deployment outdoors: An evidence-based approach

The benefits of available automatic external defibrillators (AEDs) for out-of-hospital cardiac arrests (OHCAs) are well known, but strategies for their deployment outdoors remain somewhat arbitrary. Our study sought to assess different strategies for AED deployment.All OHCAs in Paris between 2000 and 2010 were prospectively recorded and geocoded. A guidelines-based strategy of placing an AED in locations where more than one OHCA had occurred within the past five years was compared to two novel strategies: a grid-based strategy with a regular distance between AEDs and a landmark-based strategy. The expected number of AEDs necessary and their median (IQR) distance to the nearest OHCA were assessed for each strategy.Of 4176 OHCAs, 1372 (33%) occurred in public settings. The first strategy would result in the placement of 170 AEDs, with a distance to OHCA of 416 (180-614) m and a continuous increase in the number of AEDS. In the second strategy, the number of AEDs and their distance to the closest OHCA would change with the grid size, with a number of AEDs between 200 and 400 seeming optimal. In the third strategy, median distances between OHCAs and AEDs would be 324m if placed at post offices (n=195), 239 at subway stations (n=302), 137 at bike-sharing stations (n=957), and 142 at pharmacies (n=1466).This study presents an original evidence-based approach to strategies of AED deployment to optimize their number and location. This rational approach can estimate the optimal number of AEDs for any city.