In Silico Trial of Optimized Versus Actual Public Defibrillator Locations

Christopher L F Sun; Lena Karlsson; Christian Torp-Pedersen; Laurie J Morrison; Steven C Brooks; Fredrik Folke; Timothy C Y Chan

doi:10.1016/j.jacc.2019.06.075

In Silico Trial of Optimized Versus Actual Public Defibrillator Locations

J Am Coll Cardiol. 2019 Sep 24;74(12):1557-1567. doi: 10.1016/j.jacc.2019.06.075.

Authors

Christopher L F Sun¹, Lena Karlsson², Christian Torp-Pedersen³, Laurie J Morrison⁴, Steven C Brooks⁵, Fredrik Folke², Timothy C Y Chan⁶

Affiliations

¹ Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
² Department of Cardiology, Copenhagen University Hospital Gentofte, Copenhagen, Denmark; Emergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark.
³ Department of Health, Science, and Technology, Aalborg University, Aalborg, Denmark.
⁴ Division of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Rescu, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
⁵ Rescu, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; Department of Emergency Medicine, Queen's University, Kingston, Ontario, Canada.
⁶ Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada; Rescu, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada. Electronic address: tcychan@mie.utoronto.ca.

PMID: 31537265
DOI: 10.1016/j.jacc.2019.06.075

Abstract

Background: Automated external defibrillators (AEDs) are often placed in areas of low risk and limited temporal availability. Mathematical optimization can improve AED accessibility but has not been compared with current practices.

Objectives: This study sought to determine whether, compared with real AED locations, optimized AED locations improve coverage of out-of-hospital cardiac arrests (OHCAs).

Methods: The authors conducted the first retrospective in silico trial of an AED placement intervention. This study identified all public OHCAs of presumed cardiac cause and real AED deployed (control group) from 2007 to 2016 in Copenhagen, Denmark. Optimization models trained on historical OHCAs (1994 to 2007) were used to optimize an equal number of AEDs to the control group in locations with availabilities based on building hours (intervention #1) or 24/7 access (intervention #2). The 2 interventions and control scenario were compared using the number of OHCAs that occurred within 100 m of an accessible AED ("OHCA coverage") during the 2007 to 2016 period. Change in bystander defibrillation and 30-day survival were estimated using multivariate logistic regression.

Results: There were 673 public OHCAs and 1,573 registered AEDs from 2007 to 2016. OHCA coverage of real AED placements was 22.0%. OHCA coverage of interventions #1 and #2 was significantly higher at 33.4% and 43.1%, respectively; relative gains of 52.0% to 95.9% (p < 0.001). Bystander defibrillation increased from 14.6% (control group) to 22.5% to 26.9% (intervention #1 to intervention #2); relative increase of 52.9% to 83.5% (p < 0.001). The 30-day survival rates increased from 31.3% (control group) to 34.7% to 35.4%, which is a relative increase of 11.0% to 13.3% (p < 0.001).

Conclusions: Optimized AED placements increased OHCA coverage by approximately 50% to 100% over real AED placements, leading to significant predicted increases in bystander defibrillation and 30-day survival.

Keywords: automated external defibrillator; cardiac arrest; public access defibrillation; resuscitation.

Publication types

Comparative Study

MeSH terms

Aged
Computer Simulation*
Defibrillators*
Denmark
Female
Health Services Accessibility
Humans
Male
Middle Aged
Out-of-Hospital Cardiac Arrest / therapy*
Public Facilities
Retrospective Studies