Performing chest compressions during the initial phase of out-of-hospital cardiac arrest: continuous vs. alternating (CALM) – a study protocol for prospective, randomised, monocentric, non-blinded, mannequin study with German emergency medical servic

The protocol was approved by the ethics committee of the University of Heidelberg (S-252/2025, June 04, 2025). It is registered with the German Clinical Trials Register (DRKS00037157, June 10, 2025). Participation will be voluntary and based on informed consent. Data will be recorded only in a pseudonymised form. After completion, data will be kept on file for 10 years. The findings will be disseminated in a peer-reviewed academic journal. De-identified data from the case report form will be made publicly available within the first publication. The study will be conducted following the Declaration of Helsinki and relevant laws.