Bystander automated external defibrillator application in non-shockable out-of-hospital cardiac arrest.

Background: An increasing proportion of patients with OHCA present with non-shockable rhythms, among whom the benefit from AED application is not known.

Methods: We performed a retrospective analysis of adults with non-traumatic, public, bystander-witnessed, non-shockable OHCA occurring between 2005-2015 at 9 locations participating in the Resuscitation Outcomes Consortium. Non-shockable arrest was defined as when no shock was administered by a bystander applied AED and confirmed by the initial rhythm on EMS arrival. Outcomes were compared between patients with non-shockable OHCA in whom a bystander AED was or was not applied.

Results: Among 2809 patients with non-shockable public, witnessed OHCA, 8.4% had an AED applied. CPR was more often performed in the AED-applied group (99% vs. 51% of patients, p < 0.001). Among patients in whom an AED was not applied, 39.8% had any pre-hospital ROSC, 29.6% had a pulse at ED arrival and 11.1% survived to hospital discharge compared to 44.1%, 29.6% and 9.7%, respectively with AED application. After adjustment for the Utstein variables excluding bystander CPR, the OR for survival to hospital discharge for AED application was 0.90 (95% CI:0.57-1.42); when adjusted for the higher frequency of CPR in the AED group the OR was 0.92 (95% CI:0.57-1.47).

Conclusions: The application of an AED in non-shockable public witnessed OHCA was associated with a higher frequency of bystander CPR. The probabilities of pre-hospital ROSC, pulse at ED arrival, and survival to hospital discharge were not altered by the application of an AED.