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

Objective: To evaluate the effect of the introduction of automated external defibrillators (AEDs) on survival after in-hospital 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% Cl, 0.84-2.04) and the relative risk of survival to hospital discharge was 1.33 (95% Cl, 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. Crit Care Resusc 2009; 11: 261-265