This analysis will be based on data from the national electronic based Danish OHCA registry. Data on OHCAs with resuscitative attempts in Denmark have been collected in the electronic based Danish Medical Service report system since 2016. The registry covers detailed data including the EMS report, executive entries, and advanced text searches of prehospital charts. All cases go through an elaborate validation process where all identified events are read through manually by an external verification team. This ensures high quality of data, collected according to the Utstein recommendations, throughout the approximately 5400 cases of OHCA in Denmark annually. During this verification process, supplementary sources of data are linked to each OHCA, among others information about survival, localization, initiation of bystander CPR and EMS personnel operation.
The goal of this observational study is to investigate characteristics in out-of-hospital cardiac arrests (OHCA) related to sex differences.~The main questions it aims to answer are:~are there possible differences in help provision by bystanders, cardiopulmonary resuscitation (CPR), pre-hospital treatment by emergency medical services (EMS)?~are there differences in the presence of shockable initial rhythm (SIR) and survival rates after OHCA at successive stages of treatment? Researchers will compare all emergency medical services treated resuscitations in Denmark between 2016 and 2021 to see if there are possible differences between sexes.