Objectives: Automated external defibrillators (AEDs) provide an opportunity to improve survival in out-of-hospital, ventricular fibrillation (VF) cardiac arrest by enabling laypersons not trained in rhythm recognition to deliver lifesaving therapy. The potential role of emergency dispatchers in the layperson use of AEDs is uncertain. This study was performed to examine whether dispatcher telephone assistance affected AED skill performance during a simulated VF cardiac arrest among a cohort of older adults. The hypothesis was that dispatcher assistance would increase the proportion who were able to correctly deliver a shock, but might require additional time.
Methods: One hundred fifty community-dwelling persons aged 58-84 years were recruited from eight senior centers in King County, Washington. All participants had received AED training approximately six months previously. For this study, the participants were randomized to AED operation with or without dispatcher assistance during a simulated VF cardiac arrest. The proportions who successfully delivered a shock and the time intervals from collapse to shock were compared between the two groups.
Results: The participants who received dispatcher assistance were more likely to correctly deliver a shock with the AED during the simulated VF cardiac arrest (91% vs 68%, p = 0.001). Among those who were able to deliver a shock, the participants who received dispatcher assistance required a longer time interval from collapse to shock [median (25th, 75th percentile) = 193 seconds (165, 225) for dispatcher assistance, and 148 seconds (138, 166) for no dispatcher assistance, p = 0.001].
Conclusions: Among older laypersons previously trained in AED operation, dispatcher assistance may increase the proportion who can successfully deliver a shock during a VF cardiac arrest.