Background: Over 60% of out-of-hospital cardiac arrests (OHCA) that occur in public locations have an initial shockable rhythm, making these patients optimal for rapid defibrillation by a bystander with an automatic external defibrillator (AED). We recently reported that survival to hospital discharge was 67% (2011-2015) if the patient is shocked by a bystander vs 45% in EMS shock. Substantial resources have been invested over the last ten years to increase the proportion of OHCA that are shocked by a bystander. In Europe, police have been successfully utilized to increase the rate of AED application.
Methods: We assessed the rate of bystander and police AED shock in shockable observed public OHCA (SOP-OHCA) for 9 Resuscitation Outcomes Consortium (ROC) sites from 2005-2015. The overall and site-specific rate of bystander AED shock was analyzed longitudinally via spline interpolation. The American Red Cross and American Heart Association provided training statistics and Philips, Zoll, Physio Control and Markets and Markets provided AED sales data by region.
Results: There were 4692 SOP-OHCA, of which 740 were shocked by a bystander. The percent of SOP-OHCA with bystander shock was 10% in 2005 and increased to 22% in 2015 (see figure). In 2015 this varied among ROC sites from 7% to 35%. There was an apparent temporal association of intensified training by the American Red Cross and the American Heart Association and greater bystander AED use for the site with the largest increase in bystander AED use. There was no appreciable association between increased AED sales as recorded by the manufacturers and AED shocks. Police applied the AED in 10% of bystander AED applications.
Conclusions: AED shock by bystanders in SOP-OHCA increased significantly from 2005-2015. Police were only a minor contributor to overall bystander AED applications in OHCA at ROC sites. Nonetheless, major advances in bystander use at ROC sites appear sensitive to intensified community efforts.