Background:

Annually English NHS Ambulance Services treat over 30,000 out-of-hospital cardiac arrest (OHCA) patients. Defibrillation is one of the most effective treatments and if delivered within a few minutes of an arrest, over half the people treated survive. However, despite ambulance services best efforts less than 10% survive, because in many cases it takes too long for an ambulance to get to the patient. It is now possible for members of the public to use an automated external defibrillator (AED), however, for them to make best use of these machines they need to be in the right places. AEDs have been placed in public locations but their placement in the community has not been coordinated that makes them unavailable to treat the majority of OHCAs.

Policy and Practice Partners:

Prof. Theodoros Arvanitis, Warwick Manufacturing Group

Dr Lazaros Andronis, Warwick Clinical Trials Unit

Dr Ranjit Lall, Warwick Clinical Trials Unit

Dr Christopher Smith, Warwick Clinical Trials Unit

Prof. Aloysius Siriwardena, University of Lincoln

Dr Gareth Clegg, University of Edinburgh

Dr Steven Brooks, Queens University, Kingston, Ontario, Canada

Prof Charles Deakin, University of Southampton

Prof Timothy Chan, University of Toronto, Canada

Mr John Long, PPI

Co-Funding partners:

NIHR Health Services and Delivery Research Programme

Aims and Objectives:

The project aims to optimise the placement of public access AEDs in England, using mathematical modelling techniques, to maximise the likelihood that an individual suffering an OHCA will have access to public access defibrillation, improving their chances of survival. To assess the cost-effectiveness of optimised public access AED placement compared to current practice. The specific project objectives are:

1. Determine the current coverage of known public access AEDs relative to historical OHCAs.

2. Model the locations of different deployment strategies (based on building types and grid centroids) for public access AEDs.

3. Develop a mathematical optimisation model for AED deployment, accounting for spatial and temporal accessibility.

4. Determine the costs and benefits associated with the placement strategies developed and compare these against current practice.

Methods:

This is a retrospective analysis of data from the OHCA Outcomes registry, supplemented by AED location information available at each English Ambulance Service, and the location of different building types (e.g. pubs, places of worship, schools, etc.). Using geographic information systems software, we will examine where OHCAs have occurred in relation to where AEDs are located to determine whether each OHCA is covered. We will then see if putting a defibrillator in specific building types improves the coverage. We will also examine whether placing an AED in the centre of every 1km2 grid in the country or census output area also has an impact on coverage. Lastly, we will analyse the impact of a mathematical optimisation model on coverage. Once this is completed we will then undertake a cost-effectiveness analysis of the various strategies to determine the most economical strategy.

Main Results:

Not available yet

Conclusions:

Not available yet

Implications for Implementation:

There is a need for the research to understand where the best location for AEDs are to improve the likelihood they will be used to treat an OHCA, and therefore increase the chances of survival.