Cardiac arrest in children: A Europe-wide epidemiological study on out-of-hospital cardiac arrest in children. A protocol for a subgroup analysis of the European registry of cardiac arrest THREE study.

Background: Out-of-hospital cardiac arrest affecting children may result in death or hypoxic brain injury, with potentially devastating consequences for children, families, and societies. Efforts to reduce this impact require sound knowledge of current epidemiology. This protocol outlines a study of the epidemiology of out-of-hospital cardiac arrest in persons aged <18 years across 28 European countries. Methods/design: The European Registry of Cardiac Arrest (EuReCa) THREE study, a prospective, multi-centre cohort study, collected data for cases of out-of-hospital cardiac arrest between September 1st and November 30th 2022. This paediatric substudy will analyse features of cardiac arrests in children. Subsequently, the paediatric group will be compared to a cohort of younger adults (18-65 years) to identify differences. Incidences of out-of-hospital cardiac arrest will be calculated using relevant population data and presented per 100,000 child- and person-years for participating countries and overall, alongside national groupings of precipitating causes underlying cardiac arrest. Logistic regression will be performed to identify modifiable factors impacting the outcomes survived event and survival to hospital discharge or 30 days. Independent variables will include features of cardiac arrest, including presumed cause, witnessed status, shockable rhythm, epidemiological, and resuscitation factors. Logistic regression analysis results will be displayed in tables, and statistical significance set at the 0.05 level. Discussion: The results will be used to identify possible targets for preventing cardiac arrest, e.g. by raising awareness of important causes among the public and healthcare providers. Furthermore, the study may identify opportunities for optimising resuscitation chains in Europe to improve outcomes.