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

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Wilderness and Rescue Medicine

the use of medication and desensitizing exposure to cold and hot stimulus. Risk Versus Benefit Rewarming deep frostbite is a high-risk field treat- ment primarily because you will have rendered your patient incapable of using his or her hands or feet. This can be a real survival problem in some situations. Even so, it can be difficult to convince a person not to rewarm when the opportunity presents itself. It may be counterintuitive, but the discovery of fully frozen feet is not an invitation to warm up by the campfire. It is a mandate to return to the trailhead and find a hospital immediately. The formation of blisters and swelling in rewarmed frostbite is an indication of moderate tissue damage that would become devastating with additional mechanical trauma or refreezing. Continuing use of an extremity in this condition risks permanent damage and infection, yet people routinely overlook this to finish a race series or bag one more peak. This is unwise under any cir- cumstance and can be lethal if critical mobility becomes impaired. The prevention of frostbite is not just a convenience; it is an essential survival skill.

General Principles

Trench Hands

The mechanism is prolonged vasoconstriction in cold and wet conditions.

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Raynaud’s Phenomenon Raynaud’s is a disorder of the blood vessels near the skin, most often affecting the hands and fin- gers and aggravated by cold exposure. Profound vasoconstriction causes temporary ischemia, with the typical white or blue appearance and numb- ness and tingling. Raynaud’s is usually self-limit- ing if the extremity is protected from further cold exposure. Predisposing factors include repetitive use injury, vibration injury, and previous cold frostbite. Raynaud’s can also be a feature of other systemic illness.

General Principles

Raynaud’s Phenomenon

“With Raynaud’s, profound vasoconstriction causes temporary ischemia, with the typical white or blue appearance and numbness and tingling.”

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Of primary concern in backcountry medicine is that Raynaud’s patients are at high risk for frostbite in freezing weather and for prolonged ischemia in cool weather, with the attendant tis- sue breakdown and inflammation. These people need to be especially conscientious about wear- ing gloves and staying warm and well hydrated. Definitive treatment is prolonged and may involve