Accidental hypothermia can be of multiple aetiologies and is often related to an accident in a cold environment and contrasts with urban hypothermia. People living in the cold such as workers, fishermen and military personnel are at risk. More recently there is an increase in unprepared lay people practicing leisure activities such as winter sports, thus exposing themselves to hypothermia in case of an accident. Most of the cases concern mild hypothermia which does not need hospitalization or medical assistance. In contrast, deep hypothermia, with or without cardiac arrest, is rare and carries a high mortality in healthy adults and children [1, 2, 3].

Induced hypothermia which has been used for cardiac surgery as well as therapeutic hypothermia used for brain ischaemia, are medically indicated and highly monitored and therefore cannot be compared to accidental hypothermia. Patients with induced hypothermia may reach the same degree (< 28°C) but are in controlled narcosis and are normally cooled down and rewarmed by Cardiopulmonary Bypass (CPB) [4]. Therapeutic hypothermia cools the patient to mild hypothermia (32–34°C) to enhance a better and faster functional brain recovery [5].

The concept of applying the technique of CPB rewarming, as used in induced deep hypothermic cardiac arrest, to victims of accidental hypothermia with temperatures below 28°C and cardio-respiratory arrest was initiated successfully by Prof. Ueli Althaus at the University Hospital Insel in Bern, Switzerland over 30 years ago [6]. Since that time our team and other Swiss universities started to use this method and we published a multi-centre study showing a long-term sequelae-free survival rate of 47% after rewarming of 32 deep accidental hypothermic patients in cardiac arrest using cardiopulmonary bypass (CPB) [7]. Due to the fact that many patients died from post-rewarming complications, we and others have shown the beneficial effect of using extra-corporeal life support (ECLS) such as prolonged ECMO use after rewarming for cardiovascular and pulmonary dysfunctions [8, 9].