Transient mild hypothermia (core body temperature 35-32°C) is common and usually without consequences for the brain or other organs. However, prolonged severe accidental hypothermia (core body temperature below 28°C) due to accidents is rare, and usually fatal in more than 50% of cases. Little is known on its physiopathology, on prognostic factors for rewarming decision or ideal rewarming techniques for better survival. Furthermore, complications after successful rewarming are extremely frequent and very often severe or fatal.

Accidental hypothermia is a frequent problem during the winter months and can be caused by snow sport accidents, near drowning and urban cold exposure. The International Hypothermia Registry's principle goal is to increase knowledge on accidental hypothermia by creating the largest database on accidental hypothermia which will comprise enough patient data to give a statistical power since the causes of accidental hypothermia and its treatment varies greatly.

The International Hypothermia Registry (IHR) will enable improvement of pre- and in-hospital treatment and rewarming methods, study survival predictors and prevention of post-rewarming complications. By this way, the IHR will permit the establishment of evidence-based diagnosis and treatment guidelines.

The aim of the International Hypothermia Registry is to improve rescue, treatment and outcome of accidental hypothermia victims.

The principal objectives of the International Hypothermia Registry are:

• Improving the outcome of accidental hypothermic patients (survival and normal neurologic function);
• This outcome is dependent on the presenting status of the patient (temperature, trauma, cardiac arrest, etc.);
• The hospital treatment and rewarming method will also influence the outcome, invasive vs. non-invasive rewarming and rewarming rate.
• Quality control, assessment of hypothermia cases

This IHR is mainly prospective but retrospective entries are welcome.

There is no data limit on retrospective cases: cases of any year can be entered.

Inclusion Criteria:

• Accidental hypothermia with body core temperatures equal or less than 35°C/95°F;
• Any cause leading to accidental hypothermia (e.g. mountain, water, urban);
• Any age, gender, or comorbidities;
• Any pre-hospital and hospital treatment and rewarming;
• Any outcome.

Exclusion Criteria:

• Patient opposition to be part of a study;
• Essential missing values, e.g. temperature.

The investigators aim to include patients of any age.