OBJECTIVE: There is international variation in the rates of bystander cardiopulmonary resuscitation (CPR). 'Bystander CPR' is defined in the Utstein definitions, however, differences in interpretation may contribute to the variation reported. The aim of this cross-sectional survey was to understand how the term 'bystander CPR' is interpreted in Emergency Medical Service (EMS) across Europe, and to contribute to a better definition of 'bystander' for future reference.

METHODS: During analysis of the EuReCa ONE study, uncertainty about the definition of a 'bystander' emerged. Sixty scenarios were developed, addressing the interpretation of 'bystander CPR'. An electronic version of the survey was sent to 27 EuReCa National Coordinators, who distributed it to EMS representatives in their countries. Results were descriptively analysed.

RESULTS: 362 questionnaires were received from 23 countries. In scenarios where a layperson arrived on scene by chance and provided CPR, up to 95% of the participants agreed that 'bystander CPR' had been performed. In scenarios that included community response systems, firefighters and/or police personnel, the percentage of agreement that 'bystander CPR' had been performed ranged widely from 16% to 91%. Even in scenarios that explicitly matched examples provided in the Utstein template there was disagreement on the definition.

CONCLUSION: In this survey, the interpretation of 'bystander CPR' varied, particularly when community response systems including laypersons, firefighters, and/or police personnel were involved. It is suggested that the definition of 'bystander CPR' should be revised to reflect changes in treatment of OHCA, and that CPR before arrival of EMS is more accurately described.