Which building types give optimal public access defibrillator coverage for out-of-hospital cardiac arrest?

Public access defibrillation is a key component of the early links in the chain of survival. Despite growing numbers of PADs in the community, actual use remains poor, partly because of the difficulties in locating the nearest PAD. We aimed to establish the cover that would be provided if PADs were located in any given building type, which would enable the public to know where the nearest PAD was located.

Mapping software was used to classify each and every building type in the South Central Ambulance Service region. The 52 commonest building types were then mapped to all cardiac arrest calls in the same geographical area from Jan 2014 - July 2018. The walking distance from each cardiac arrest to each nearest building type was calculated.

A total of 22,382 cardiac arrests were mapped to a total of 24,155 buildings considered suitable for potential PAD location. Post boxes ranked first in both urban and rural areas, covering 11.7% of cardiac arrests at 100 m and 85.6% of cardiac arrests at 500 m. In urban areas, bus shelters and telephone boxes also provided good coverage (9.7%, 9.5% @ 100 m; 69.2%, 71.9% @ 500 m respectively). In rural areas, good coverage was provided by nursing/care homes and pubs/bars (4.9%, 4.6% @ 100 m; 15.2%, 31.8% @ 500 m respectively).

Locating PADs at all post boxes would provide the most effective geographical coverage in both urban and rural areas according to building type. This may be an effective strategy to improve rapid PAD locating.