Overcoming Spatial and Temporal Barriers to Public Access Defibrillators Via Optimization.

Area of Science:

• Public Health
• Emergency Medicine
• Health Informatics

Background:

• Immediate access to automated external defibrillators (AEDs) is critical for out-of-hospital cardiac arrest (OHCA) survival.
• Current AED deployment strategies primarily focus on spatial accessibility, often assuming 24/7 availability.
• This assumption overlooks temporal accessibility, leading to potential gaps in emergency response coverage.

Purpose of the Study:

• To develop an optimization model for AED deployment that incorporates both spatial and temporal accessibility.
• To evaluate the improvement in OHCA coverage compared to deployment models based solely on spatial accessibility.
• To quantify the coverage loss attributed to limited temporal access of AEDs.

Main Methods:

• Retrospective population-based cohort trial using cardiac arrest data from Toronto.
• Identified nontraumatic public OHCAs and registered AED locations.
• Developed a spatiotemporal optimization model to maximize AED coverage, considering actual availability times.

Main Results:

• A significant coverage loss of 21.5% was observed when considering AED temporal availability versus assumed 24/7 access.
• The spatiotemporal optimization model achieved a 25.3% relative increase in actual OHCA coverage compared to spatial-only deployment.
• One in five OHCAs occurred near an AED that was not available at the time of the event.

Conclusions:

• A substantial proportion of OHCAs occur when nearby AEDs are inaccessible due to time constraints.
• Spatiotemporal optimization of AED deployment significantly enhances potential AED utilization.
• Integrating temporal factors into AED deployment models is crucial for improving OHCA survival rates.