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I immigrated to the USA at the invitation of the University of Iowa to start what was probably the first academic hand surgery unit in the USA. The winter temperatures were so extreme that I seriously thought of returning to damp but mildly cold England. In my first Iowa winter I experienced temperatures of −30°F and had to dig down through the snow to find my mailbox—and I saw my first cases of frostbite.
Potential patients are policemen, farmers, mail carriers, homeless people, chronic alcoholics, psychiatric patients, fishermen, victims of automobile breakdowns, and returning recreational skiers (1).
Our bodies are thought to conserve body heat by first constricting vessels to organs not essential to life. The areas first affected are those furthest from the heart, “ears and nose, fingers and toes.” Frostbite occurs when unprotected skin is exposed to temperatures of 21°F; the insult is made worse by cold winds. The tissues freeze and ice crystals form in the cells. Most cells can survive freezing and subsequent thawing, but the small blood vessels are usually so damaged that clots obstruct the circulation. This risk is increased in those with diabetes or Raynaud's disease, as well as heavy alcohol consumers (1).
Those exposed to the risk of frostbite need to wear layers of insulated nonconstrictive clothing and protect themselves from moisture. Our feet are particularly susceptible; gravity drains sweat into one's socks, increasing the risk of frostbite. Swedish research has shown that wet socks combined with motion may reduce insulation protection by 45% (1).
Frostbite is described in four degrees:
This is a useful classification, but it is important to realize that tissue damage may not be disclosed in frostbitten areas for many days. In severe cases, treatment must be expected to last a number of weeks and entail several sessions of surgical debridement and skin grafting.
The best immediate treatment for hands and feet is placing them in warm water at 40° to 41°C (104° to 107°F) for at least 30 minutes. The water temperature must be constantly checked and maintained at the proper temperature. The patient should be given sponges to repeatedly dunk in the water and hold over the nose or ears if they are affected.
As thawing occurs, the area will turn red and nerve reactivation will produce pain, for which strong medication may be needed. Massage to the frozen areas is not recommended, nor is holding the frostbitten site in front of an open fire, which will cause desiccation of the affected area.
After the water immersion, intact blisters should be wrapped in dry gauze dressings. Ruptured blisters should be debrided; raw areas should be treated with antibiotic ointment and covered with nonadherent dressings. Hemorrhagic blisters should not be drained unless they are infected.
Severe and late cases with blackened digits, nose, and ears must be kept under observation and allow adjacent tissues to recover as much circulation as they can before amputation is considered (2, 3).
Early aggressive debridement will risk removing potentially viable tissue. The only rational surgical care is to delay tissue excision except for draining any infection beneath scarred tissue and relieving any constrictions caused by the scarred tissue (2, 3).
A severe case is illustrated in the Hand Exhibit in Truett Lobby by the kindness of Beck Weathers, MD, who was “left for dead” on Everest mountain in a 1996 expedition. His right hand had to be amputated and his left hand has only three “stump” fingers, a central and one on either side. He continues to practice as a pathologist in Medical City Hospital.
Recently, thrombolytic therapy is being tried in severe cases using agents such as tissue plasminogen activator. I have no personal experience with this therapy, and references 4 to 7 are informative.
There are two long-term problems. In children, damage to digital epiphyses leads to growth irregularities and shortening (Figure (Figure33). Adults often show early onset of arthritis in digital joints.
P.S. Note to Dallas readers: Frostbite is not associated with 12½ inches of snow!