CURRENT Essentials of Critical Care.pdf

Chapter 17 Environmental Injuries 249■■■FrostbiteEssentials of Diagnosis• Superficial frostbitten skin and subcutaneous area typically painless,numb, blanched; deep frostbite area may have woody appearance• Occurs when tissues become frozen; may see line of demarcationbetween frozen and unfrozen areas• Severity of frostbite best determined after rewarming; first degreewith hyperemia, edema, no blisters; second degree addsblisters, pain during rewarming; third degree with skin necrosis,eschars, hemorrhagic blisters; fourth degree with completesoft tissue, muscle, bone necrosisDifferential Diagnosis• Peripheral arterial disease• Raynaud disease• Necrotizing fasciitis, cellulitis• Immersion foot (prolonged exposure to cold water, non-freezinginjury)Treatment• Limit cold exposure as soon as possible; avoid rewarming if refreezinglikely• Rewarm extremities in warm water bath between 40–42°C; continuerewarming until all blanched tissues perfused with blood• Opioid analgesics for pain during rewarming; epidural blockduring lower extremity rewarming can be used• Débride white-blistered tissue after rewarming• Aloe vera, applied topically every 6 hours to affected areas, andibuprofen both inhibit thromboxane; may reduce tissue injury• Antibiotic prophylaxis, usually with penicillin, for 48–72 hours• Avoid amputation until amount of tissue loss clearly defined;may be weeks or months after injury• Treat likely concomitant hypothermia■ PearlFrostbite rarely occurs unless environmental temperature is less than6.7°C (20°F).ReferenceMurphy JV et al: Frostbite: pathogenesis and treatment. J Trauma 2000;48:171.[PMID: 10647591]