Automated external defibrillators and in-hospital cardiac arrest: patient survival and device performance at an Australian teaching hospital

Abstract

Aims: To evaluate the effect of automated external defibrillators (AEDs) on patient survival and to describe the performance of AEDs after in-hospital cardiac arrest.

Methods: Prospectively collected data were analysed for cardiac arrests in the general patient care areas of a teaching hospital during the 3 years before and the 3 years after the deployment of AEDs. The association between availability of an AED and survival to hospital discharge was assessed using multivariate logistic regression. AED performance during automated management of the initial rhythms was assessed using information captured by the AEDs.

Results: There were 84 cardiac arrests in the AED period and 82 in the pre-AED period. Patient and event characteristics were similar in each period. The initial rhythm was shockable in 16% of cases. Return of spontaneous circulation was higher in the AED period (54% vs. 35%, P=0.02) but the proportion of hospital survivors in each period was similar (22% vs. 19%, P=0.56). The adjusted odds ratio for hospital survival when an AED was available was 1.22 (95% CI 0.53-2.84, P=0.64). An AED was applied in 77/84 (92%) possible cases. Median interruption to chest compressions was 12s (inter-quartile range 12-13). An automated shock was delivered in 8/13 (62%) possible cases.

Conclusions: Availability of AEDs was not independently associated with hospital survival. Shockable presenting rhythms were not common and, in keeping with the manufacturer's specifications, the AEDs did not shock all potentially shockable rhythms. The hands-off time associated with automated rhythm management was considerable.