The frequencies of autonomous bystander-initiated cardiopulmonary resuscitation (CPR) and public access defibrillation have not yet been clarified. We aimed to evaluate the frequency of autonomous actions by citizens not having a duty to act.

This retrospective observational study included patients who suffered an out-of-hospital cardiac arrest (OHCA) in Tokyo between January 1, 2013 and December 31, 2017. The Delphi method with a panel of 11 experts classified the locations of OHCA resuscitations into 3 categories as follows; autonomous, non autonomous, and undetermined. The locations determined as autonomous were further divided into 2 groups; home and other locations. Bystander-initiated CPR and application of an automated external defibrillator (AED) pad were evaluated in 43,460 patients with OHCA.

Group A (non autonomous), group B (autonomous, not home), and group C (home), consisted of 7,352, 3,193, and 32,915 patients, respectively. Compared with group A, group B and group C had significantly lower rates of bystander-initiated CPR (group A, B, C; 68.3% versus 38.6% versus 23.9%) and AED pad application (groups A, B, C; 26.8% versus 15.1% versus 0.6%). In addition, multivariate analysis demonstrated that an autonomous location of resuscitation was independently associated with the frequencies of bystander-initiated CPR and AED pad application, even after adjusting for age, sex, and witness status.

Autonomous actions by citizens were unacceptably infrequent. Therefore, the education and training of citizens is necessary to further enhance autonomous CPR.