Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Section V: Environmental Medicine

Rewarmed frostbite is a high-risk wound. Early surgical referral is indicated. Blister formation will occur over hours to days, and the sloughing of dead tissue will continue for weeks. With com- petent treatment, most of the damaged tissue can be salvaged. The spontaneous rewarming of deep frostbite without the benefit of warmwater immersion has been shown to produce a worse outcome but may be the side effect of rewarming and protecting a cold patient. As a treatment, it is a last resort. However, most experts agree that it is better than intentionally keeping a foot or hand frozen while Anything that restricts the circulation of warm blood to tissues allows freezing to occur more readily. In people who are already a little chilled, shell/core compensation reduces perfusion to the extremities to maintain core temperature. Constricting clothing such as ski boots or a splint tied too tightly can reduce blood flow as well. Cigarette smoking is an additional in core temperature factor, infusing the body tissues with nicotine, which is a powerful vasoconstrictor. Certainly, well-insulated and fitted boots, gloves, and a face mask can go a long way toward prevent- ing frostbite in extreme conditions. But equally important is maintaining an active and warm body core. This ensures a good supply of warm blood to the extremities. That is why proper nutri- tion and warm clothing are so important. the rest of the patient is rewarmed. Prevention of Frostbite

Trench Foot Trench foot is an example of one of the several conditions that develop with prolonged exposure to cold and wet conditions above freezing. It is not limited to feet and often involves the hands of paddlers, fishermen, and others working or playing on the water. Inflammation results from prolonged vasoconstriction and tissue breakdown, an example of ischemia to infarction. Blisters can develop, with the possibility of secondary infec- tion where the dermis has been exposed.

General Principles

Trench Foot

Inflammation results from prolonged vasoconstriction and tissue breakdown, an example of ischemia to infarction.

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Treatment of Trench Foot (or Hand)

Because the mechanism is ischemia from being wet and cold, the ideal treatment is to improve perfusion by keeping the feet warm and dry. Treat any open wounds to prevent infection and allow for healing. Ibuprofen may help with inflam- mation and pain. Like rewarmed frostbite, tis- sue damage can be exacerbated by further use. Walking may be difficult or impossible. Prevention is well worth the trouble. In “trench” conditions, try to give your hands and feet several dry and warm hours each day. Reverse shell/core compensation by maintaining hydration, calories, and activity. It’s okay to dry your wet socks in your sleeping bag at night, but not while wear- ing them. Take your wetsuit booties and gloves off whenever possible. Inside waterproof boots, change your socks frequently to keep your feet as dry as you can.

General Principles

• Don’t be lazy, act to correct cold response! • Stay hydrated and well fed. • Keep insulation dry. • Don’t underestimate heat loss. • Dress for the conditions. • Avoid vasoconstrictors and tight boots. Frostbite Prevention

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“Early recognition = easy cure”

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