Abstract 16773: Optimal Defibrillator Placement in a High-rise Building
Background: Increasing urbanization is leading to higher population density and more people living in high-rise buildings. This “vertical” population is subject to unique challenges in OHCA response, most importantly lower survival and longer delays until paramedic arrival on upper floors. Although optimal AED placement based on travel in two-dimensions is well-studied, there has been no analysis in the vertical dimension to date.
Objective: To determine whether elevator-based or lobby-based AED placement results in shorter response distance to OHCAs in a high-rise building.
Methods: We developed a model of a single-elevator, n-floor high-rise building. We calculated and compared the average distance from AED to floor of arrest when an AED was located in the elevator versus the lobby. We modeled OHCA occurrences using floor-specific Poisson processes and the relative risk of OHCA on the ground floor (λ1) to risk on any above-ground floor (λ). The elevator was modeled with an override function enabling direct travel to the target floor—upper floor or lobby depending on AED and OHCA locations. Elevator location upon override was modeled as a discrete uniform random variable. Calculations used the laws of probability considering all possible OHCA and elevator locations.
Results: Elevator-based AED placement had shorter average response distance in buildings where the number of floors (n) exceeded three quarters of the ratio of ground-floor OHCA risk to above-ground floor risk (λ1/λ) plus one half (n ≥ 3λ1/4λ+0.5). Otherwise, a lobby-based AED had shorter average response distance. An elevator-based AED was guaranteed to have shorter average response distance if OHCA risk was equal on all floors (if λ1=λ).
Conclusions: Elevator-based AEDs travel less distance to OHCAs in very tall buildings or those with uniform risk vertically. In buildings with substantial lobby, underground, and nearby street-level traffic and OHCA risk, lobby-based AEDs travel less distance.
Author Disclosures: T.C. Chan: None.
- © 2016 by American Heart Association, Inc.