Chapter 020. Hypothermia and Frostbite (Part 6)

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Frostbite with vesiculation, surrounded by edema and erythema.The two most common nonfreezing peripheral cold injuries are chilblain (pernio) and immersion (trench) foot. Chilblain results from neuronal and endothelial damage induced by repetitive exposure to dry cold. Young females, particularly those with a history of Raynaud's phenomenon, are at greatest risk. Persistent vasospasticity and vasculitis can cause erythema, mild edema, and pruritus. Eventually plaques, blue nodules, and ulcerations develop. These lesions typically involve the dorsa of the hands and feet. In contrast, immersion (trench) foot results from repetitive exposure to wet cold above the freezing point. The feet initially appear...

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Chapter 020. Hypothermia and Frostbite (Part 6) Frostbite with vesiculation, surrounded by edema and erythema.The two most common nonfreezing peripheral cold injuries are chilblain (pernio) and immersion (trench) foot. Chilblain results from neuronal and endothelial damage induced by repetitive exposure to dry cold. Young females, particularly those with a history of Raynaud's phenomenon, are at greatest risk. Persistent vasospasticity and vasculitis can cause erythema, mild edema, and pruritus. Eventually plaques, blue nodules, and ulcerations develop. These lesions typically involve the dorsa of the hands and feet. In contrast, immersion (trench) foot results from repetitive exposure to wet cold above the freezing point. The feet initially appear cyanotic, cold, and edematous. The subsequent development of bullae is often indistinguishable from frostbite. This vesiculation rapidly progresses to ulceration and liquefaction gangrene. Patients with milder cases complain of hyperhidrosis, cold sensitivity, and painful ambulation for many years. Frostbite: Treatment
Frozen tissue should be rapidly and completely thawed by immersion in circulating water at 37°–40°C. Rapid rewarming often produces an initial hyperemia. The early formation of large clear distal blebs is more favorable than smaller proximal dark hemorrhagic blebs. A common error is the premature termination of thawing, since the reestablishment of perfusion is intensely painful. Parenteral narcotics will be necessary with deep frostbite. If cyanosis persists after rewarming, the tissue compartment pressures should be monitored carefully. Numerous experimental antithrombotic and vasodilatory treatment regimens have been evaluated. There is no conclusive evidence that dextran, heparin, steroids, calcium channel blockers, hyperbaric oxygen, or prostaglandin inhibitors salvage tissue. A treatment protocol for frostbite is summarized in Table 20-4. Table 20-4 Treatment for Frostbite Before During Thawing After Thawing Thawing Remove Consider parenteral Gently dry and protect from environment analgesia and ketorolac part; elevate; pledgets between toes, if macerated
Prevent Administer ibuprofen, If clear vesicles are partial thawing and 400 mg PO intact, aspirate sterilely; if refreezing broken, debride and dress with antibiotic or sterile aloe vera ointment Stabilize Immerse part in 37°– Leave hemorrhagic core temperature 40°C (thermometer- vesicles intact to prevent and treat monitored) circulating water dessication and infection hypothermia containing an antiseptic soap until distal flush (10–45 min) Protect Encourage patient to Continue ibuprofen frozen part—no gently move part 400 mg PO (12 mg/kg per friction or massage day) q8–12h Address If pain is refractory, Consider tetanus and medical or surgical reduce water temperature to streptococcal prophylaxis; conditions 35°–37°C and administer elevate part
parenteral narcotics Hydrotherapy at 37°C Consider phenoxybenzamine in severe cases Unless infection develops, any decision regarding debridement or amputation should be deferred until there is clear evidence of demarcation, mummification, and sloughing. Magnetic resonance angiography may demonstrate the line of demarcation earlier than clinical demarcation. The most common symptomatic sequelae reflect neuronal injury and the persistently abnormal sympathetic tone, including paresthesias, thermal misperception, and hyperhidrosis. Delayed findings include nail deformities, cutaneous carcinomas, and epiphyseal damage in children. Management of the chilblain syndrome is usually supportive. With refractory perniosis, alternatives include nifedipine, steroids, or limaprost, a prostaglandin E1 analogue. FURTHER READINGS Brieva J et al: Severe hypothermia: Challenging normal physiology. Anesth
Intensive Care 33:662, 2005 [PMID: 16235489] Danzl DF: Accidental hypothermia, in Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed, J Marx et al (eds). St. Louis, Mosby, 2006, p 2236 Ervasti O et al: The occurrence of frostbite and its risk factors in young men. Int J Circumpolar Health 63:71, 2004 [PMID: 15139242] Giesbrecht GG: Cold stress, near drowning and accidental hypothermia: A review. Aviat Space Environ Med 71:733, 2000 [PMID: 10902937] Jurkovich GJ: Environmental cold-induced injury. Surg Clin North Am 87(1):247, viii, 2007 Kempainen RR, Brunette DD: The evaluation and management of accidental hypothermia. Respir Care 49:192, 2004 [PMID: 14744270] Vassal T et al: Severe accidental hypothermia treated in an ICU: Prognosis and outcome. Chest 120:1998, 2001 [PMID: 11742934]