Bystanders' willingness to assist using automated external defibrillators during cardiac arrest.

The "bystander effect," in which the presence of others inhibits rescue actions, has not been specifically examined in the context of cardiac arrest; understanding this effect in relation to rescue with automated external defibrillators (AEDs) is important. This study aims to identify the presence of others as a factor inhibiting rescue actions using an AED, from a social psychology perspective. We collected data through a web-based questionnaire involving registered residents in all 47 prefectures of Japan. The participants were presented with hypothetical scenarios of witnessing cardiac arrest events at train stations, under sparse or crowded conditions, and with or without the presence of competent parties (e.g., station staff or security guards). Their willingness to intervene was assessed across three levels of rescue behavior: (1) running and calling for help, (2) retrieving an AED, and (3) using an AED. This study found evidence of the bystander effect, indicating that the presence of competent others reduced behavioral interventions by bystanders during out-of-hospital cardiac arrest (OHCA) events. Moreover, the perceived presence of competent parties at the scene of a cardiac arrest reduced bystanders' willingness to initiate rescue under certain circumstances. While many bystanders were willing to initiate rescue efforts in response to calls for help, they resisted rescues involving an AED. This study observes that a bystander effect occurs among bystanders witnessing OHCA, explores the inhibiting effects of identifying competent parties on the initiation of rescue efforts, and suggests that there are significant invisible barriers to using AEDs in rescuing patients with OHCA.