Automated external defibrillators and survival after in-hospital cardiac arrest: early experience at an Australian teaching hospital

Abstract

Objective: To evaluate the effect of the introduction of automated external defibrillators (AEDs) on survival after inhospital cardiac arrest.

Design, setting and participants: Before-and-after study that compared patients during the 2 years before (8 November 2005 to 7 November 2007) and the year after (8 November 2007 to 7 November 2008) the deployment of AEDs to the non-critical care areas of a university teaching hospital.

Main outcome measures: Return of spontaneous circulation (ROSC) and survival to hospital discharge.

Results: 55 in-hospital cardiac arrests occurred in the 2-year pre-AED period and 31 in the 1-year AED period. Patients had similar baseline characteristics in the pre-AED and AED periods including witnessed arrest (53% v 48%), arrest in an acute inpatient ward (78% v 90%), and initial arrest rhythm of pulseless ventricular tachycardia or ventricular fibrillation (18% v 16%). The proportions of patients with ROSC were similar in the pre-AED and AED periods (42% v 55%), as were the proportions who survived to hospital discharge (22% v 29%). In the AED period, the relative risk of ROSC was 1.31 (95% CI, 0.84- 2.04) and the relative risk of survival to hospital discharge was 1.33 (95% CI, 0.63-2.80).

Conclusions: ROSC and survival to hospital discharge did not change significantly after deployment of AEDs. The existence of a timely and robust resuscitation response with relatively good baseline outcomes, and the low proportion of initial shockable arrest rhythms may have limited the capacity of AEDs to improve survival.