Frostbite is trauma from exposure to freezing temperatures and actual freezing of the tissue fluids in the cell and intercellular spaces. It results in cellular and vascular damage. Body parts most frequently affected by frostbite include the feet, hands, nose, and ears. Frostbite ranges from first degree (redness and erythema) to fourth degree (full-depth tissue destruction).
A frozen extremity may be hard, cold, and insensitive to touch and may appear white or mottled blue-white. The extent of injury from exposure to cold is not always initially known. The history of the patient should include environmental temperature, duration of exposure, humidity, and the presence of wet conditions.
The goal of management is to restore normal body temperature. Constrictive clothing and jewelry that could impair circulation are removed. If the lower extremities are involved, the patient should not be allowed to ambulate.
Controlled yet rapid rewarming is instituted. The extremity is usually placed in a 37° to 40°C (98.6° to 104°F) circulating bath for 30- to 40-minute spans. This treatment is repeated until cir-culation is effectively restored. Early rewarming appears to de-crease the amount of ultimate tissue loss. During rewarming, an analgesic for pain is administered as prescribed, because the re-warming process may be very painful. To avoid further mechanical injury, the body part is not handled. Massage is contraindicated.
Once rewarmed, the part is protected from further injury and is elevated to help control swelling. Sterile gauze or cotton is placed between affected fingers or toes to prevent maceration. A foot cradle may be used to prevent contact with bedclothes if the feet are involved. Blebs, which develop 1 hour to a few days after rewarming, are left intact and not ruptured, especially if they are hemorrhagic.
A physical assessment is conducted with rewarming to observe for concomitant injury, such as soft tissue injury, dehydration, alcohol coma, or fat embolism. Problems such as dehydration, hyperkalemia, and hypovolemia, which occur frequently in people with frostbite, are corrected. Risk for infection is also great; there-fore, strict aseptic technique is used during dressing changes, and tetanus prophylaxis is administered as indicated. Antiinflammatory medication is also prescribed.
Additional measures that may be carried out when appropri-ate include the following:
· Whirlpool bath for the affected extremity to aid circulation, debride necrotic tissue, and help prevent infection
· Escharotomy (incision through the eschar) to prevent fur-ther tissue damage, allow for normal circulation, and permit joint motion
· Fasciotomy to treat compartment syndrome
After rewarming, hourly active motion of the affected digits is encouraged to promote maximal restoration of function and to prevent contractures. Refreezing is avoided. The patient is also encouraged to avoid tobacco, alcohol, and caffeine because of their vasoconstrictive effects, which further reduce the already de-ficient blood supply to injured tissues.
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