Author + information
- Received April 7, 2019
- Revision received June 6, 2019
- Accepted June 16, 2019
- Published online September 16, 2019.
- Christopher L.F. Sun, PhDa,
- Lena Karlsson, MDb,c,
- Christian Torp-Pedersen, MD, DMScd,
- Laurie J. Morrison, MDe,f,
- Steven C. Brooks, MDf,g,
- Fredrik Folke, MD, PhDb,c and
- Timothy C.Y. Chan, PhDa,f,∗ (, )@uoftmie@UofT
- aDepartment of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
- bDepartment of Cardiology, Copenhagen University Hospital Gentofte, Copenhagen, Denmark
- cEmergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark
- dDepartment of Health, Science, and Technology, Aalborg University, Aalborg, Denmark
- eDivision of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- fRescu, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
- gDepartment of Emergency Medicine, Queen’s University, Kingston, Ontario, Canada
- ↵∗Address for correspondence:
Dr. Timothy C.Y. Chan, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Office MC315, Toronto, Ontario M5S 3G8, Canada.
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.
This work was supported by the Danish foundation TrygFonden with no commercial interest in the field of cardiac arrest. Dr. Torp-Pedersen has received grant support from Bayer for a clinical trial and Novo Nordisk for an epidemiological study. Dr. Morrison has received financial support from the Canadian Institute of Health Research, the Heart and Stroke Foundation of Canada, and the American Heart Association. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Listen to this manuscript's audio summary by Editor-in-Chief Dr. Valentin Fuster on JACC.org.
- Received April 7, 2019.
- Revision received June 6, 2019.
- Accepted June 16, 2019.
- 2019 American College of Cardiology Foundation
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