Public access defibrillation: a shocking idea?

Currently, survival from out-of-hospital cardiac arrest in the United Kingdom is poor. Ambulance response standards require that an ambulance reach 75 per cent of cardiac arrests within 8 min. But a short time to defibrillation from the onset of collapse is a key predictor of outcome from out-of-hospital cardiac arrest. The Department of Health has recently implemented a lay responder defibrillation programme, with the aim of shortening this time interval for victims in public places. This initiative utilizes automated external defibrillators (AEDs), which provide written and recorded voice prompts to minimize training requirements and errors in use. Lay responder AED programmes with very short response times have reported survival to discharge rates of up to 53 per cent for patients presenting in ventricular fibrillation (VF). This compares well with the results of a meta-analysis that reported a survival rate of only 6.4 per cent for traditional defibrillator-equipped ambulance systems. The annual incidence of out-of-hospital cardiac arrest in England is 123 per 100,000 population. Approximately half of these present in VF, and could benefit from an AED programme. But only 16 per cent of cardiac arrests occur in a public place. It has been calculated that there are approximately 5,000 instances of VF in public places each year in England. If half of these patients can be reached and administered a first shock within 4 min of their collapse, an additional 400 victims may survive each year. Given the current investment by the DoH of 2 million pounds, this suggests a cost per life saved of approximately 505 pounds over a 10 year period.