Climbing often takes us to high, wild places with harsh conditions. And one consequence of prolonged exposure to cold temperatures and high winds can be frostbite: the freezing and subsequent death of body tissues. Frostbite generally occurs to extremities that are farthest from the heart, including the fingers, toes, nose, ears, cheeks, and chin. It can cause permanent numbness or loss of use of the affected area, and, in the worst cases, the body part must be amputated. Avoiding temperatures below freezing is impossible for high-altitude and winter climbers, so it’s essential to know how to prevent and treat this destructive ailment.
Environment. The three main risk factors for frostbite are temperature, wind chill, and the length of time of exposure. The wind chill chart (fig.1) is an excellent resource to determine risk for frostbite.
Gear. Tight clothing, ill-fitting boots, rings, watches, and bracelets— anything that restricts circulation—can contribute to the onset of frostbite. Wet clothing and prolonged contact to metal items can also be a factor. Proper-fitting clothing that is layered to prevent overheating and sweating is essential.
Nutrition. Dehydration, alcohol, smoking, and poor diet can all negatively affect circulation and contribute to frostbite.
Frost nip. In this first stage, affected tissue becomes white and numb, and it may have a waxy appearance. The tissue will recover, often within 30 minutes of rewarming, but it might become red and swollen. Sensation loss is possible.
Superficial frostbite. This level includes freezing of the skin and other underlying tissue. The damaged area will be pale, waxy, cold, hard, and have a loss of sensation. However, deeper tissue such as muscle and bone are not affected. After rewarming, blisters will appear, tissue will be red and swollen, and the affected area will eventually become hard and blackened. This often appears worse than the actual damage inflicted.
Deep/severe frostbite. This has the same characteristics as superficial frostbite, but will include deeper tissue such as muscles, tendons, blood vessels, and nerves. They will become hard and have zero sensation. Purple blisters will develop and turn black—some may be filled with blood. There may be some leakage of fluid, followed by blackened and gangrenous lesions. The affected areas might fall off or require amputation.
Warning: Rewarming in the field should only be done if there is no possibility of evacuation to a controlled environment.
Before treating frostbite, address any life-threatening conditions related to trauma or altitude illness.
Management of hypothermia also takes priority over frostbite. The climber should be moved to a warm, dry shelter immediately to prevent further heat loss.
If possible, evacuate the patient to a controlled environment for rewarming.
Handle the affected body parts with extreme care to prevent further injury. If possible, do not let a patient walk on frostbitten feet.
Remove wet or restrictive clothing on affected parts. Remove any constrictive jewelry.
If evacuation is not possible and rewarming must be conducted, immerse the affected tissue in clean water at 104°F (40°C). Stir water to promote transfer of heat evenly over the affected region and to prevent overheating the water. Air-dry the body part.
You can also rewarm by placing affected areas against a partner’s heat-producing groin or armpits.
Pain medication (ibuprofen) should be given during and after the rewarming process. If available, an antibiotic such as ciprofloxacin or amoxicillin will prevent infection.
Ensure the climber is wellhydrated.
After rewarming, protect limb from any direct pressure, dress wounds with bulky sterile dressings, and keep blisters intact.
Rub frostbitten skin and tissue.
Attempt to rewarm using a fire or stove.
Rewarm if there is any possibility of refreezing.
Allow the tissue to refreeze if it is successfully thawed.
Red: Frostbite within five minutes at this temperature and wind. Gray: Frostbite within 10 minutes at this temperature and wind. White: Frostbite within 30 minutes at this temperature and wind.Adapted from Wilderness Medicine by Paul Auerbach (page 797, 5th Edition)