The Usability of Five Automated External Defibrillators by Minimally Trained Bystanders

Cardiac Arrest (SCA) by enabling more timely access to defibrillation. An AED should ideally be designed so that minimally trained bystanders can effectively and safely operate the device and deliver the necessary shock. This study evaluates the usability of five AEDs by bystanders with only a basic understanding of AED functionality and use. Methods- 125 subjects were recruited to participate as bystander rescuers. Each of the five AEDs was evaluated by a different set of 25 randomly assigned subjects. Subjects were first asked to review a brief memo that provided generic AED instructions. Subjects then deployed the assigned AED and delivered a shock to a simulated victim of cardiac arrest. The principle outcome was successful use of the AED, defined as safe and effective defibrillation shock delivery. The secondary outcome was time to shock, defined as the time from first contact with the AED to delivery of defibrillation shock. Subjects also completed a questionnaire to evaluate their experience using the AED. Results- The successful use rates for the Defibtech Lifeline (92%), Philips HeartStart OnSite (84%), Medtronic LifePak CRPlus (72%), and Zoll AED Plus (72%) were statistically equivalent (p>0.05 for all comparisons), while the successful use rate for the Cardiac Science PowerHeart G3 (36%) was substantially lower (p<0.05) due to inaccurate pad placement. Time to shock for the Medtronic LifePak CRPlus (63 sec), Defibtech Lifeline (64 sec), Cardiac Science PowerHeart G3 (69 sec), and Philips HeartStart OnSite (79 sec) were statistically equivalent (p>0.05 for all comparisons), while time to shock for the Zoll AED Plus (114 sec) was substantially greater (p<0.05). Subjects rate