Introduction Public access defibrillation doubles the chances of neurologically intact survival following out-of-hospital cardiac arrest (OHCA). Although there are increasing numbers of defibrillators (automated external defibrillator (AEDs)) available in the community, they are used infrequently, despite often being available. We aimed to match OHCAs with known AED locations in order to understand AED availability, the effects of reduced AED availability at night and the operational radius at which they can be effectively retrieved.
Methods All emergency calls to South Central Ambulance Service from April 2014 to April 2016 were screened to identify cardiac arrests. Each was mapped to the nearest AED, according to the time of day. Mapping software was used to calculate the actual walking distance for a bystander between each OHCA and respective AED, when travelling at a brisk walking speed (4 mph).
Results 4012 cardiac arrests were identified and mapped to one of 2076 AEDs. All AEDs were available during daytime hours, but only 713 at night (34.3%). 5.91% of cardiac arrests were within a retrieval (walking) radius of 100 m during the day, falling to 1.59% out-of-hours. Distances to rural AEDs were greater than in urban areas (P<0.0001). An AED could potentially have been retrieved prior to actual ambulance arrival in 25.3% cases.
Conclusion Existing AEDs are underused; 36.4% of OHCAs are located within 500 m of an AED. Although more AEDs will improve availability, greater use can be made of existing AEDs, particularly by ensuring they are all available on a 24/7 basis.
- cardiac arrest
- health care delivery
- cardiac arrhythmias and resuscitation science
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Contributors CDD conceived the work. Data were collected by SA and GAH. Data analysis and interpretation was performed by CDD and SA. All authors drafted the article, critically revised it and gave final approval of the version to be published.
Funding This study was funded by a research grant from the Resuscitation Council (UK).
Competing interests CDD has received grants from the Resuscitation Council (UK) of which he is a member and is the ILCOR domain lead for ’Defibrillation'. All authors are employees of South Central Ambulance Service.
Patient consent Not required.
Ethics approval The National Health Service classified this study as a service evaluation and as such does not require ethics approval.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The authors will share non-patient identifiable data for the purposes of verification of the results of this study.
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