Hypothermia

Hypothermia is defined as core body temperature of less than 35 degrees Celsius. It can be divided into mild (temp 32 - 35), moderate (temp 28 - 32) and severe (< 28). It can also be classified as either Primary (exposure hypothermia) or Secondary. The latter is seen in the elderly, ill or intoxicated and will not be discussed here.

Risks for hypothermia in the adventure or wilderness setting include exposure (low temperatures, wind chill, wet clothing, immersion), trauma (head injuries, immobility), malnutrition, and alcohol.

Patients with mild hypothermia experience uncontrollable shivering, lethargy, confusion or unusual behaviour, urinary frequency and loss of coordination. Moderate hypothermia presents with slow breathing and pulse, loss of shivering, decreased level of consciousness and delerium. Patients with severe hypothermia are unconscious, cold to touch, have difficulty breathing and abnormal heart rhythms and may appear dead.

Treatment of hypothermia starts with prevention of further cooling. Remove wet clothes, apply warm blankets and avoid further exposure to cold environment. Warmed sweet drinks may be helpful. Avoid alcohol. Apply hot water bottles or commercial heat packs to the head, neck, armpits and groin. If severe, place the patient in a pre-warmed sleeping bag with another person. Use skin to skin contact to promote head transfer. Patients with moderate or severe hypothermia need urgent hospital care.