Usability of Automated External Defibrillators by untrained Bystanders in a Simulated Cardiac Arrest Scenario

Background Public Access Automated External Defibrillators (AEDs) are intended for use by laypersons during out–of-hospital cardiac arrest, yet bystander use remains limited. Usability differences between devices may influence AED deployment in emergency situations. Methods A randomized comparative simulation study evaluated four commercially available AEDs used by untrained participants in a standardized adult cardiac arrest scenario. Objective task performance measures and subjective usability ratings were collected and analyzed using one-way ANOVA with post-hoc testing. Results Significant differences were observed across devices, particularly during pad placement, shock delivery, and initiation of cardiopulmonary resuscitation (p < 0.0001). Devices providing clearer visual and verbal instructions were associated with faster task completion, higher accuracy, and greater user confidence. Conclusions AED usability varies substantially across devices. Human factors-driven design features that reduce cognitive load may improve bystander AED use in emergency settings. Trial registrations: not applicable