Salt Lake City, UT – It may be hard to think about frostbite and hypothermia as summer chugs onward, but winter isn’t far off and brushig up now on how to deal with hypothermia and frostbite could make all the difference once the snow starts flying.
Hypothermia, the result of the inability to overcome heat loss by the generation and conservation of body heat, can be acute or chronic, according to a recent article in the journal Wilderness Medicine authored by Dr. Sam Schimelpfenig, M.D. Acute signifies a sudden drop of core body temperature, and chronic hypothermia is when there is a gradual drop in core temperature. Surprising to some, chronic hypothermia is more common, often occurring in ambient temperatures between 30 and 50 degrees Fahrenheit.
More important than the classification is the recognition of the signs and symptoms. An easy way to remember this is by remembering the “umbles” —- mumbling, grumbling, fumbling, and stumbling —- that represent the intellectual and physical impairments often observed.
Hypothermia can be further divided into mild, moderate, or severe hypothermia. Patients with mild hypothermia will be able to rewarm themselves as long as the symptoms are recognized and treated appropriately. In mild hypothermia (associated with a core temperature in the 90°F to 95°F range) the shivering mechanism will be very active as the body attempts to generate body heat through muscular contraction. The patient can also be recognized by slurred speech, fatigue and irritability, a loss of fine motor coordination, and ataxia. Setting up a tent or finding shelter, getting into dry clothes and a sleeping bag, and sipping a hot drink are good places to start. Heat sources can be applied to areas such as the chest and armpits, taking care not to place the heat sources directly against the skin to avoid burning the patient. The process of shivering consumes a large amount of energy, and the patient may feel exhausted even after he or she is rewarmed. As their shivering stops and their symptoms improve, patients can resume gradual activities as conditions permit as long as they are well hydrated, better prepared, and feel up to it.
If hypothermia is not recognized and treated early, the core temperature will continue to drop and the patient progresses from mild to severe hypothermia. Patients with moderate and severe hypothermia will not be able to rewarm themselves, and the application of any external sources of heat, including body-to-body rewarming, will likely be inadequate, so they should be evacuated to a medical facility immediately. The shivering mechanism slows and eventually stops. The patient’s mental status continues to deteriorate resulting in irrational behavior, apathy, and eventual unconsciousness. A patient with severe hypothermia will be unconscious, cold to the touch, and have faint vital signs that are often difficult to detect.
Patients with hypothermia in the moderate (core temperature 82°F to 90°F) or severe (core temperature less than 82°F) range should be handled gently as there is a risk of inducing ventricular fibrillation with aggressive movements. External heat sources should be applied to the neck, armpits, chest, and groin, again using care to avoid burns, although there is some debate as to how effective these measures actually are at rewarming the patient. Caution should be used in giving anything by mouth to avoid aspiration, as is the case in any patient with an altered mental status. Avoid extremity massage, the theory being that the cold blood returning to the core can actually lower the patient’s temperature further and may also induce ventricular fibrillation.
Hypothermia can be difficult to manage, but is much easier to prevent. Maintaining an adequate amount of energy intake and hydration is vital. Dressing appropriately and having a few extra layers available may seem obvious but is easy to forget, especially if one is only planning a short foray into the outdoors. If traveling alone, ask yourself the question, “What would I do if I got cold?” When traveling in a group, remain constantly vigilant so that hypothermia can be recognized and treated early.
Whereas hypothermia involves a reduction of the core temperature, frostbite is a local process and is the result of actual freezing of the cells and soft tissues. Risk factors for frostbite include freezing temperatures, high wind and altitude, tobacco and drug use, contact with heat-conducting materials such as metal, and a previous history of frostbite.
Like hypothermia, frostbite can occur in varying degrees. The degree of severity —- superficial, partial-thickness, or full-thickness frostbite, the most severe -— determines the course of action that needs to be taken. Superficial frostbite, also called frostnip, can be recognized by a small patch of white skin that rapidly goes away with warming. No specific care is needed although the area may remain painful for weeks to months afterward. Partial thickness frostbite is the freezing of the deeper layers of skin, and is recognized by pale, cold, and numb skin; the underlying tissues, however, remain soft and mobile. As long as there is no danger of refreezing, the area should be rewarmed as quickly as possible. Refreezing after the area has been thawed has been shown to cause much more extensive damage.
Rewarming can be accomplished by immersion in warm circulating water or by direct contact with a warm object, but can be problematic to do in the field. After rewarming, the skin will likely develop blistering with a clear fluid; blistering with bloody fluid indicates more severe frostbite.
Frostbite can be extremely painful, and the patient should be given analgesics such as ibuprofen prior to rewarming. The area should be treated in a similar manner to a burn with local wound care and prevention of infection. Once in a
medical facility, these patients may require extensive debridement of devitalized tissue.
Full thickness frostbite involves both the skin and the underlying soft tissue. The affected body part will be cold and non-pliable, often described as feeling “like a block of wood.” These patients need to be immediately evacuated. Pain control will again be an issue and damage to the skin and underlying tissue can be extensive. As is the case with partial thickness frostbite, these patients will need long-term follow-up. Amputation should be delayed for as long as possible to allow accurate demarcation of viable tissue.
The severity of a frostbite injury has been shown to be most related to the duration of time the area remained frozen. However, one needs to consider the chance of refreezing, progression of the frostbite, and the ease of evacuation when managing frostbite in the field. In cases of full thickness frostbite of a foot, for example, it may be better to allow the patient to walk out on his own rather than try to carry him out, or not to warm an area that will then become painful.
Frostbite is often seen in high-risk types of activities such as high-altitude mountaineering but can also occur in unplanned situations closer to home. It is important to recognize the loss of sensation or an inability to move the affected area and seek immediate ways to reverse the situation. Take time to periodically check in with everyone in the group and make sure they are paying attention to their own bodies as well.