Cardiac arrest occurs frequently and the outcome after out-of-hospital resuscitation is often fatal. Disturbing is that more than half of the surviving patients suffer from permanent impairment of cognitive functions, such attention, memory and executive functioning. With all the efforts to achieve a high quality initial resuscitation management the time delay between cardiac arrest and the beginning the initial resuscitation maneuver is the main reason for the still poor outcome. To shorten this fatal time delay, current efforts of national and supranational health authorities aime at the non-medically trained lay person, who should carry out basic life support directly on the scene supported by the use of public available semi-automatic defibrillators (AED).

It is a combined retrospective and prospective observational single center study. Data of all Out of Hospital patients suffered a cardiac arrest in Zurich city will be collected according to the Utstein criteria. The aim of this study is to investigate the impact of trained police forces in the resuscitation outcome.

Inclusion Criteria:

• All Out of hospital patients suffering cardiac arrest in Zurich City, resuscitated by lay persons, city police and or trained emergency medical services

Exclusion Criteria:

• individuals with cardiac arrest occurring in the presence of EMS
• individuals in whom there were apparent toxic, traumatic or suicidal etiologies for unconsciousness
• drowned individuals and individuals with terminal illness
• documented negation of data collection

Out of hospital patients suffered or suffering cardiac arrest, who were or will be resuscitated by laypersons, city police and/or trained emergency medical services teams who were called to the emergency