The Potential for Bystander Automated External Defibrillator Deployment in London, UK

Christopher M Smith, Ranjit Lall, Gavin D. Perkins
Clinical Trials Unit, Warwick Medical School, University of Warwick, CV4 7AL, UK

Purpose: Bystander Automated External Defibrillator (AED) use is associated with increased survival from out-of-hospital cardiac arrest (OHCA) [1]. However, it is only used in a minority of cases, limiting its effectiveness at population level [2]. The effective coverage area of an AED (the maximum distance it can be from an OHCA to be deployed effectively) is a subject for debate, but a range of 100m to 500m are often quoted in the literature [2]. The aim of this study was to determine the proximity of OHCA to AEDs in London, to assess the current potential for bystander AED use.
Materials and Methods: We obtained the locations of OHCA in the area served by London Ambulance Service between 1st April 2016 and 31st March 2017 from the national OHCA Outcomes Registry, and the locations of AEDs known to London Ambulance Service. We have mapped these locations using ArcGIS (Geographical Information Systems) software. Subsequently, we will calculate the proportion of OHCA occurring within 100m, 200m, 300m, 400m, 500m of the nearest AED.
Results: There were xxxx OHCA and 2948 AEDs registered with London Ambulance Service in this time period. Results available by July 2018 will report upon the number of OHCA occurring within the specified distances of the nearest AED, as measured by both a simple radius and by using actual walking distance (using paths, roads etc.)
Conclusions: These results will give an indication of the potential for bystander AED in London. Comparing this to the actual rate of bystander AED use will indicate the additional potential for bystander AED in London. 

References

1.	Holmberg MJ, Vognsen M, Andersen MS et al. Bystander automated external defibrillator use and clinical outcomes after out-of-hospital cardiac arrest: A systematic review and meta-analysis. Resuscitation 2017;120:77-87

2.	Smith CM, Lim Choi Keung SN, Khan MO et al. Barriers and facilitators to public access defibrillation in out-of-hospital cardiac arrest: a systematic review. Eur Heart J Qual Care Clin Outcomes 2017;3:264-273

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