Dispatcher assistance and automated external defibrillator performance among elders

Objectives: Automated external defibrillators (AEDs) provide an opportunity to improve survival in out-of-hospital, ventricular fibrillation (VF) card iac arrest by enabling laypersons not trained in rhythm recognition to deli ver lifesaving therapy. The potential role of emergency dispatchers in the layperson use of AEDs is uncertain. This study was performed to examine whe ther dispatcher telephone assistance affected AED skill performance during a simulated VF cardiac arrest among a cohort of older adults. The hypothesi s was that dispatcher assistance would increase the proportion who were abl e to correctly deliver a shock, but might require additional time. Methods: One hundred fifty community-dwelling persons aged 58-84 years were recruit ed from eight senior centers in King County, Washington. All participants h ad received AED training approximately six months previously. For this stud y, the participants were randomized to AED operation with or without dispat cher assistance during a simulated VF cardiac arrest. The proportions who s uccessfully delivered a shock and the time intervals from collapse to shock were compared between the two groups. Results: The participants who receiv ed 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). Am ong those who were able to deliver a shock, the participants who received d ispatcher assistance required a longer time interval from collapse to shock [median (25th, 75th percentile) = 193 seconds (165, 225) for dispatcher as sistance, and 148 seconds (138, 166) for no dispatcher assistance, p = 0.00 1]. Conclusions: Among older laypersons previously trained in AED operation , dispatcher assistance may increase the proportion who can successfully de liver a shock during a VF cardiac arrest.