Researchers in Scotland used records of all out of hospital cardiac arrests due to heart disease from 1991-1998 to estimate the potential impact of public access defibrillators on overall survival after out of hospital cardiac arrest.
Of 15,189 arrests, 79% occurred in sites not suitable for the location of public access defibrillators, such as the person's home or a friend's home. Only 453 (3%) occurred in possibly suitable sites, such as buses and multi-storey car parks, and 18% occurred in suitable sites, such as shops, places of business, and sports centres.
The authors predict that locating public access defibrillators only in suitable sites would increase the survival rate from 5.0% to 6.3%. If defibrillators were located in suitable and possibly suitable sites, the survival rate would increase only slightly further to 6.5%.
This predicted increase in survival is less than the increase achievable through expansion of early defibrillation provision to non-ambulance first responders, such as other emergency services or community schemes, or of bystander cardiopulmonary resuscitation, explain the authors. Even so, the Department of Health is committed to providing 700 public access defibrillators in 72 sites across England and Wales.
Additional resources for wide scale coverage of public access defibrillators are probably not justified by the marginal improvement in survival, they conclude.