The hazards of exposure to cold on board, part 1
By Gino C. Bottino, M.D.
In part 1 of a two-part series on cold exposures, we’ll take a look at local cold injuries, including chilblain, immersion injuries of the hands and feet, trench foot and frostbite.
Although frequently unrecognized, chilblain is common. Some people, usually thin people, are prone to it. Chilblain mostly affects the hands and sometimes the lower extremities.
Chilblain is characterized by a bluish-red skin and mild swelling along with itching, burning and occasionally pain with movement of the fingers hands and feet. If exposure occurs on a regular basis, the condition can become chronic and persistent, leaving the skin discolored for long periods.
To treat, remove the offended areas from exposure, rewarm the exposed areas, and apply a soothing ointment to the skin.
Immersion exposures and trench foot
Unlike chilblain, immersion exposures and trench foot occur when extremities or shoe-clad feet have been immersed in water usually below 60 degrees Fahrenheit but above freezing. It occurs only after a prolonged exposure.
Clinical manifestations include swelling, skin discoloration and blistering with numbness, tingling, pain, itching and muscle cramping. Like chilblain, trench foot can be a chronic condition, and secondary infections are common. The treatment is the same as for chilblain.
The term “frostbite” is reserved for injuries with tissue destruction. Pain only occurs early on or not at all, and as the tissues freeze, only a sensation of numbness remains. The patient may not even be aware of the frostbite until someone mentions it. When the damage is superficial, the surface will feel hard but the underlying tissues will feel soft when depressed gently and firmly. In deep frostbite, the entire area feels hard.
The most important aspects of treatment are getting the patient to a place of ultimate treatment before immediately and rapidly thawing and rewarming the exposed areas. In deep frostbite, the rewarming process can lead to serious complications and death. For this reason, patients should be transported to a facility where they will ultimately be treated before beginning rewarming.
Even moderate-size superficial frostbite can lead to serious complications and must be taken seriously. In the field or onboard when transportation to a treatment facility may be many days away, first provide general warmth to the patient and plenty of fluids. Do not give alcohol. Then, as quickly as possible, immerse the affected extremity in water heated to 105 to 107 degrees Fahrenheit. Test water temperature frequently to maintain the correct temperature. Wet heating will thaw an area four times as fast as air heating. This process can be very painful, and pain medications should be given beforehand. After thawing, treat the area as a burn. Dead tissues may need to be cut away and antibiotics given.
On inland waters, any frostbite victim should be immediately transported to a treatment facility as quickly as possible. Obtain outside help, and do not take chances.
On an offshore passage where transport to a medical facility is one to three days away, rewarming should not be attempted for deep frostbite. It would be safer to wait and transfer the patient to an adequate facility for medical attention.
Gino Bottino, M.D., has had wide experience in medical practice and emergency medical matters. A member of United States Power Squadrons First Aid Support Team (FAST) and the Safety Committee, Gino also has a background in competitive sail racing and is familiar with health-related problems afloat.
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