• environmental medicine, hypothermia

Accidental hypothermia has become much better understood over the last 25 years. Not only is it recognised that it significantly worsens the prognosis if it occurs alongside many medical conditions including major trauma1 2 and elective surgery,3 but it is also well established that severe accidental hypothermia (core temperature <28°C) is eminently survivable if treated correctly, even in the presence of cardiac arrest.4 In practice, hypothermia can be divided into two groups: mild hypothermia (core temperature 32°−35°C, table 1) and everything else. In the presence of trauma, mild hypothermia starts at 36°C,5 reflecting its deleterious effect on outcome. Mild hypothermia is very common so prehospital and hospital staff will have experience managing it. The condition per se is not lethal and there is a lot of latitude regarding general management and to which hospital a patient is taken. By contrast, severe hypothermia is relatively rare and very unforgiving. There are special requirements for managing the patient with wet clothes, packaging and the use of heat. Above all, the peri-arrest and cardiac arrest situations must be managed differently from the normothermic patient. Moving a patient with severe hypothermia can easily trigger a cardiac arrest that is resistant to treatment until rewarming to >30°C has occurred (thereby making the rewarming process more difficult and worsening the ultimate prognosis), and once an arrest has occurred, resuscitation should not be stopped until the patient is warm. Personnel who rarely encounter patients with hypothermia cannot be reasonably expected to remember all the special requirements …