Evaluate and treat the patient for associated systemic hypothermia, concurrent conditions, and injury. Early use of systemic analgesics is recommended for nonfrozen injuries. Fluids and electrolytes must be monitored. Hydrate patients orally or parenterally to avoid hypovolemia and to improve perfusion.
Rapid rewarming at temperatures slightly above normal body temperature may significantly decrease tissue necrosis and reverse the tissue crystallization. If there is any possibility of refreezing, the frostbitten part must not be thawed. Refreezing results in increased tissue necrosis. Ideally, the frozen extremity must not be used, but if required for evacuation, the affected frozen extremity must be padded and splinted to avoid additional injury. Rewarming is best accomplished by warm bath immersion. The frozen extremity is immersed in a moving water bath heated to 37–39°C for approximately 30 minutes until the area becomes soft and pliable to the touch. In the absence of a thermometer, the temperature may be checked by an unaffected extremity, ideally of a caregiver rather than the patient. Water in this temperature range feels warm but not hot to the normal hand or wrist. If warm water is not available, then passive thawing in a warm environment must be allowed. Dry heat (eg, stove or open fire) is not recommended because it is more difficult to regulate and increases the likelihood of accidental burns. Thawing may cause tenderness and burning pain. Once the frozen part has thawed and returned to normal temperature (usually in about 30 minutes), discontinue external heat. In the early stage, rewarming by exercise, rubbing, or friction is contraindicated. The patient must be kept on bed rest with the affected parts elevated and uncovered at room temperature. Avoid application of casts, occlusive dressings, or bandages. Blisters must be left intact unless signs of infection supervene.
2. Anti-infective measures and wound care
Frostbite increases susceptibility to tetanus and infection. Tetanus prophylaxis status must be verified and updated as needed. Infection risk may be reduced by aseptic wound care and protection of skin blebs from physical contact. Wounds must be kept open and allowed to dry before applying dressings. Nonadherent sterile gauze and fluffy dressing must be loosely applied to wounds and cushions used for all areas of pressure. Topical aloe vera cream or gel should be applied to the thawed tissue before application of dressings. Antibiotics should not be administered empirically. Systemic antibiotics are reserved for deep infections not responding to local wound care. Whirlpool therapy at 37–39°C twice daily for 15–20 minutes for a period of 3 or more weeks helps cleanse the skin and debride superficial sloughing tissue.
B. Medical and Surgical Treatment Options
Telemedicine may be used so that specialists can provide advice on early field treatment of cold-injured patients in remote areas, thereby improving outcomes. Nonsteroidal anti-inflammatory drugs should be administered (in the absence of contraindications) until frostbite wounds are healed or surgical management occurs (usually for 4–6 weeks). Clinicians must watch for evidence of compartment syndrome and need for fasciotomy. The extent of cold damage and the degree of likely tissue loss can be assessed through triple phase bone scanning, magnetic resonance imaging with angiography, and technetium scintigraphy. Infrared thermography is used to assess the extent of injury in a non-freezing injury. Eschar formation without evidence of infection (even black eschar formation) may be conservatively treated. The underlying skin may heal spontaneously with the eschar acting as a biologic dressing. Rates of amputation have been reduced with the use of intravenous infusions of synthetic prostaglandins and of tissue plasminogen activators, and with intra-arterial administration of a thrombolytic within 24 hours of exposure. The rate of tissue salvage decreases with every hour of delay from rewarming to thrombolytic therapy; thrombolytic therapy should be reserved for deep injuries with the potential for significant morbidity and must include a risk-benefit analysis prior to administration of the medication by experienced providers in a facility with intensive care capabilities. Angiography can be used to monitor progress before and after treatment. There is insufficient evidence to recommend hyperbaric oxygen, heparin, or sympathectomy.
Patient education must include ongoing care of the cold injury and prevention of future hypothermia and cold injury. Gentle, progressive physical therapy to promote circulation should be instituted as tolerated. Debridement and amputation may be considered only after it is established that the tissues are necrotic.