There is considerable variation in the incidence of out-of-hospital cardiac arrest (OHCA) across Europe. The likelihood of attempted resuscitation also varies. To better understand the factors that contribute to variation, more data on incidence, management and outcomes from OHCA is required. A European, multi-centre study provides the opportunity to uncover differences throughout Europe and may help find explanations for these differences. Results may also have potential to support the development of quality benchmarking between European Emergency Medical Services (EMS).

This prospective European study will involve 27 different countries. It provides a common Utstein-based dataset, data collection methodology and a common data collection period for all participants, thereby potentially increasing comparability.

Study research questions will address the following: OHCA incidence in different European regions; incidence of cardiopulmonary resuscitation (CPR) attempted; initial presenting rhythm in patients where bystanders or EMS starts CPR or any other resuscitation intervention; rate of any return of spontaneous circulation (ROSC); patient status at handover to a hospital i.e. ROSC, ongoing CPR, dead; incidence of patients still alive 30 days after OHCA; incidence of patients discharged alive from hospital.

The participating registries will transfer unprocessed anonymised data. Transmission of aggregated data should be avoided whenever possible; only in case of limitations due to national laws or ethical requirements should a participating registry transmit aggregated data. Every single case requires a data sheet (DS). Data will be collected within the national, regional or local participating registries (either as a computer-based export from the national, regional or local registry or as a paper-based DS. After validation and anonymisation of data by participating registries the data will then be transferred only via the national coordinator (computer-based) to the study centre. National coordinators are responsible for quality control i.e. the completeness reliability and accuracy of the of data, including timely submission of data to the study management group. Every DS will be identified by a unique number, including the country and region of origin. Registries that cannot transfer unprocessed original data due to the reasons mentioned above will collect data themselves. These registries will then send aggregated data to the study centre. Participating registries must collect basic EMS data on the region and population served. This registry-specific information must only be transmitted once during the study period. Data (computer and paper-based) will be handled according to national laws concerning data security; the national coordinator is responsible for maintaining the necessary standards. Access to the data will be protected by username and password.

Inclusion Criteria:

• All patients who suffer an out of hospital cardiac arrest and are attended by the EMS at any stage during the event.

Residents of 27 European countries