Prospective observational study to evaluate the body temperature difference in patients in out of hospital cardiac arrest on site and at arrival at the hospital.~If the patient fulfills the inclusion criteria and after establishment of CPR measures according the ERC resuscitation guidelines (2015 or newer) an esophageal probe will be inserted and bodytemperature is measured; on site ambiental temperature will also be measured. Weather conditions, altitude on site, activity of the patient and hypothermia protection (eg. clothes) will bei documented. On arrival in hospital the body temperature will be measured with the esophageal probe;
A prospective observational study aiming to monitor core temperature via an esophageal probe in out of hospital cardiac arrest during transport and until arrival in hospital. Insertion of an esophageal temperature probe will be done on scene during ongoing resuscitation manoeuvres based on European Resuscitation Council Guidelines 2015 (or newer). Environmental temperature influence and hypothermia prevention interventions will be monitored.