Functional Access to Public Defibrillators and Out-of-Hospital Cardiac Arrest Outcomes: A Population-Based Geospatial...

Area of Science:

• Public health
• Emergency medicine
• Geospatial analysis

Background:

• Public access defibrillation programs aim to increase automated external defibrillator (AED) availability.
• Real-world bystander use of AEDs remains limited, with functional accessibility not systematically evaluated.
• Functional accessibility considers the realistic ability of bystanders to retrieve and use an AED within a critical time window.

Purpose of the Study:

• To evaluate the functional accessibility of publicly installed AEDs.
• To integrate factors influencing AED usability during out-of-hospital cardiac arrest events.
• To assess the association between AED accessibility, bystander use, and survival outcomes.

Main Methods:

• Population-based geospatial analysis of 39,563 out-of-hospital cardiac arrests (2021-2023).
• Matching incidents to nearest public AEDs via network-based walking routes.
• Measuring functional accessibility by walking time/distance, stratified by urbanization, time, and location; logistic regression used to assess associations.

Main Results:

• Median walking time to nearest AED was 1.9 minutes; only 25.4% of rural arrests were within 3 minutes.
• Bystander AED use occurred in 2.9% of 17,285 resuscitation-attempted cases.
• Shorter walking time predicted AED use and survival; nighttime/residential arrests showed reduced use, with <2% bystander defibrillation at homes.

Conclusions:

• Functional accessibility is a key determinant of AED device use and survival outcomes.
• Policies should enhance 24/7 AED availability and integrate dispatcher-assisted public access defibrillation programs.
• Novel delivery systems, like drones, may be needed to overcome spatial and temporal access gaps.