Clinical Question: Do automated external defibrillator devices save lives?

Setting: Population-based

Study Design: Randomized controlled trial (nonblinded)

Allocation: Uncertain

Synopsis: In this community-based study, researchers identified 993 community facilities, such as shopping centers, gymnasiums, office buildings, and hotels, in 21 research centers throughout the United States and Canada. All of the sites had to have an identifiable group of volunteer responders, although facilities with onsite rescue personnel were excluded. All of the volunteers were trained in cardiopulmonary resuscitation (CPR) at the start of the study and were retrained two or more times during the study. Community facilities were randomized so that one half received automated external defibrillator devices and were trained to use them. The two groups were similar at baseline with the exception that the sites with automated external defibrillators had approximately 25 percent more volunteers, perhaps because of the novelty of the devices. Outcomes were assessed by blinded adjudicators after a mean of 21.5 months. The authors had two concerns: (1) the study results could have been influenced by the presence of the device that made volunteers more likely to respond to the events; and (2) classification bias could have occurred because patients in the automated external defibrillator group received early electrocardiography. Therefore, the primary outcome was simply the number of survivors in each community unit, a statistic presumably less subject to these biases. In the CPR-only sites, 107 definite cardiac arrests occurred with 15 survivors, 13 of whom were classified as normal or mildly impaired at hospital discharge. Centers with automated external defibrillator units had 128 definite cardiac arrests, 30 survivors, and 27 patients who went home in good or mildly impaired condition.

Bottom Line: Use of automated external defibrillators, accompanied by an intensive training program of local volunteers, results in a greater number of patients surviving to hospital discharge. However, the number of additional survivors (14 in 497 community facilities during a 22-month period) is relatively small, and the cost of the defibrillators is high; whether this is the best allocation of health care resources remains uncertain. (Level of Evidence: 1b)