injuries poisoning
Frostbite
Treatment of Frostbite
Rewarming in warm (37 to 39° C) water Supportive measures Local wound care Sometimes delayed surgery In the field, frostbitten extremities should be rewarmed rapidly by totally immersing the affected area in water that is tolerably warm to the touch (37 to 39° C). Because the area is numb, rewarming with an uncontrolled dry heat source (eg, fire, heating pad) risks burns. Rubbing may further damage tissue and is avoided. The longer an area remains frozen, the greater the ultimate damage may be. However, thawing the feet is inadvisable if a patient must walk any distance to receive care because thawed tissue is particularly sensitive to the trauma of walking and, if refrozen, will be more severely damaged than if left frozen. If thawing must be delayed, the frozen area is gently cleansed, dried, and protected in sterile compresses. Patients are given analgesics, if available, and the whole body is kept warm. Once the patient is in the hospital, core temperature is stabilized and extremities are rapidly rewarmed in large containers of circulating water kept at about 37 to 39° C; 15 to 30 minutes is usually adequate. Thawing is often mistakenly ended prematurely because pain may be severe during rewarming. Parenteral analgesics, including opioids, may be used. may be considered. If flow remains absent, intra-arterial or intravenous thrombolytic (fibrinolytic) therapy may be considered ( Treatment reference ). This treatment should be followed with Anti-inflammatory measures (eg, topical aloe vera every 6 hours andibuprofen400 to 600 mg orally every 8 hours) probably help. Affected areas are left open to warm air, and extremities are elevated to decrease edema. Anticoagulants, IV low molecular weightdextran, and intra-arterial vasodilators (eg, reserpine, tolazoline) have no proven clinical benefit.Phenoxybenzamine, a long-acting alpha-blocker, at a dosage of 10 to 60 mg orally once a day may theoretically decrease vasospasm and improve blood flow. For severe injury presenting within 48 hours, infusion of a prostacyclin analog such asiloprostshould be considered. Preventing infection is fundamental; streptococcal prophylaxis (eg, with penicillin) should be considered, especially if there is gross contamination or crush injury. If wet gangrene is present, broad-spectrum antibiotics are used. Treatment is given if vaccination is not up to date. If tissue damage is severe, tissue pressure is monitored (see Adequate nutrition is important to sustain metabolic heat production. Pre-thaw, consider using Doppler to assess pulses and tissue appearance. Other imaging tests include radionuclide scanning, MRI, microwave thermography, and laser-Doppler flowmetry to help assess circulation, determine tissue viability, and thus guide treatment. MRI and particularly magnetic resonance angiography may establish the line of demarcation before clinical demarcation and thus make earlier surgical debridement or amputation possible. However, whether earlier surgery improves long-term outcome is unclear. Usually, surgery is delayed as long as possible because the black carapace is often shed, leaving viable tissue. Patients with severe frostbite are warned that many weeks of observation may be required before demarcation and the extent of tissue loss become apparent. Whirlpool baths at 37° C 3 times a day followed by gentle drying, rest, and time are the best long-term management. No totally effective treatment for the long-lasting symptoms of frostbite (eg, numbness, hypersensitivity to cold) is known, although chemical or surgical sympathectomy may be useful for late neuropathic symptoms. 1.Hickey S, Whitson A, Jones L, et al: Guidelines for Thrombolytic Therapy for Frostbite.Journal of Burn Care & Research, 41:1, 2020. 