by John Browning
January 1997
During the next few months we'll hear reports that someone, or a group of individuals, got lost in the woods or on a mountain somewhere. When found, these individuals are frequently suffering from cold weather injuries, the most common being frostbite and/or hypothermia. Fortunately, most of these people survive their ordeal. Unfortunately, however, the injuries suffered can usually have been prevented with proper planning and an understanding of the conditions and the human body.
Hypothermia is a killer! Hypothermia is a general cooling of the body. As the body cools, blood is shunted from the extremities to the core in an effort to protect our organs from cooling. Unless the cooling is reversed, the inner core becomes chilled to the point that the body cannot generate heat to stay warm, thus the body loses heat faster than it can produce it.
There are two types of hypothermia. Hypothermia brought on by a gradual heat loss through respiration, evaporation or poor insulation is often referred to as "exposure". Exposure may be caused by a gradual heat loss brought on by exposure to cold conditions over a long period of time, but it is not just a "cold weather" problem. Gradual heat loss can be brought on by temperatures above freezing when other environmental factors such as wind and rain, or wind and sweat are combined with cool temperatures (30 to 60 degrees). Hypothermia brought on by rapid heat loss is called "acute" and is frequently caused by cold water immersion--either falling through the ice, or capsizing a canoe or kayak in cold water.
Early recognition of hypothermia and the proper treatment to prevent its progression, is critical to the victim's well being. As we get cold, we move about , swinging our arms, stomping our feet, wrapping our arms around our chest, all in an effort to ward off the chill. As the chilling continues, we begin to shiver, which is the body's way to try and produce more heat to preserve the normal temperature of the vital organs. We get the "umbles" (stumble, fumble, mumble, tumble, grumble). Don't be fooled by a stopping of the shivering, this could be a signal of the core temperature continuing to drop and the victim's condition is worsening, they are slipping from "mild" hypothermia (90 - 96 degrees Fahrenheit rectal) to "severe" (below 90 degrees Fahrenheit rectal). Unless these signs are recognized, and treatment started, it is possible that the victim could go into a coma and die.
In assessing a potential victim of hypothermia, it is important to assess the symptoms and not what the victim says. "I'll be all right, I'm just a little cold" is another way of saying "I'm mildly hypothermic, but I don't want to burden the rest of you by stopping right now for a warm drink, something to eat and to seek shelter from this wind." So, what would you do? I would suggest that we seek shelter from the wind, even if that means putting up the tent. Fire up the stove and fix a warm sugared drink for all. Eating a bagel and some cheese with the victim will help add fuel to the body's furnace and by eating along with the victim it encourages them to eat--no one likes to eat alone while the others are just hanging around watching.
Out of the wind, I'd make sure that the clothing our "victim" has on is dry, paying particular attention to the layer next to the skin--sweat soaked is just as bad as rain soaked, they're both wet and increase heat loss. I would increase the insulation layers to preserve what heat is being produced. If sitting, I'd make sure that we're insulated from the cold ground by sitting on our sleeping pad. I'd continue to observe the victim, if improvement is not seen fairly quickly, I would "fire up" some chemical heat packs and place inside the victim's clothing near the skin. Care needs to be taken to ensure that these packs, or any other warm object placed near the skin, don't burn the victim. Or, I'd place the victim in a sleeping bag along with heat packs, bottles filled with warm water, or another rescuer of normal body temperature. It's best to make skin to skin contact when putting two bodies in a sleeping bag. Simply placing the victim in a sleeping bag without a heat source is not enough, the problem is that their body is not generating enough heat as it is. At a minimum, their sleeping bag needs to be pre-warmed so there won't be further heat loss, and then there needs to be additional heat production to re-warm their body. Again, caution does need to be exercised though to protect the victim from being burned by objects placed close to their body to generate heat. Keep the victim awake until they recover. Continue the re-warming until the victim's core temperature has returned to normal (99 - 100 degrees Fahrenheit rectal).
If there is still no improvement, or if the victim's condition worsens either by loosing consciousness, or the core temperature continues to drop, then evacuation to definitive medical care is necessary. During treatment and evacuation, hypothermic victims need to be handled gently since they most likely have an irritable heart and rough handling may cause cardiac arrest. During evacuation, care must also be taken to continue to protect the victim from the environment and further heat loss. Additionally, severely hypothermic victims are often thought to be dead since neither a pulse nor respiration may be easily detectable. Resist the temptation to immediately start CPR, as chest compressions on a severely hypothermic person are likely to "convert" a slow, low output heart rhythm into a heart attack. Check for a carotid pulse (side of the windpipe) for a full minute before starting chest compressions. Once CPR is started, you are committed to continuing until the victim is re-warmed. You have probably heard the saying: "A hypothermic person isn't dead until they are warm and dead."
Turning to the other fairly common cold weather injury, frostbite. Unlike hypothermia, frostbite is a more localized injury. Simply stated, frostbite is the freezing of tissue and usually occurs in the toes, fingers, nose and ear lobes. Frostnip is the freezing of the top layers of skin tissue and is superficial frostbite. Frostnip is generally reversible by re-warming the area by placing a warm body part on the affected area. For example, a warm hand over a frostnipped nose or ear, frostnipped fingers under an armpit, or frostnipped toes on a partner's warm stomach. Care should be taken not to rub the affected areas though as the ice crystals in the affected tissue can tear the cells. Frostnip is characterized by numbness and redness that turns pale or yellowish looking. The top layer feels hard and rubbery but the deeper tissue remains soft. Untreated, frostnip may become frostbite.
In frostbite, the skin is white and waxy looking but the affected part now feels like wood. Treatment for frostbite includes rapid re-warming of the affected part in a water bath of 105 - 108 degrees Fahrenheit. However, if you cannot guarantee that the tissue will stay warm and not refreeze, do not re-warm it. Care must be taken to monitor the temperature of the water in order to prevent additional damage by burning the tissue. Re-warming may take 30 to 45 minutes. The water should be circulated to maintain an even temperature. As is the case with frostnip, do not rub the affected area. Thawing is completed when the skin has turned to a pink or red color, the skin is soft again and sensation has returned to the area. There is likely to be significant pain during the re-warming process, and pain medication may be given, but the victim should not be given alcohol.
After the thawing, the frostbitten part will be sensitive to further injury and must be protected. An application of aloe vera gel on the affected area, placement of gauze between frostbitten fingers and toes and a non-adherent dressing covered with sterile bandages to immobilize and protect from the cold should be applied. Care should be taken in the application of the bandages so as not to restrict blood flow to the affected area. Further use of frostbitten feet and fingers may cause further damage, thus use should be avoided when possible. An anti-inflammatory drug such as Ibuprofen should be administered as well.
Finally, if the victim is both hypothermic and frostbitten, treat the hypothermia first. Hypothermia can kill you. I've never heard of anyone dying from frostbite. Do not re-warm the frostbitten areas until the core temperature reaches 96 degrees Fahrenheit.
Prevention is still the best treatment. Extreme care must exercised when refilling stoves with white gas in cold weather. Spilling white gas on exposed skin can lead to instant frostbite. Also, touching metal with bare skin can cause your skin to freeze to the metal. Always wear gloves when working with fuels, metal stoves, tent poles, ski and snowshoe bindings, anything metal, in cold weather. Many cases of frostbitten feet have occurred due to boots that were too tight. Boots that fit well in the warmer months may be too tight when thicker socks are worn in the colder months. Dehydration and lack of enough food/fuel also contribute to cold weather injuries, as does nicotine and consumption of alcoholic beverages.
This discussion is only on two of the more common cold weather injuries. I've also written about Cold Water Immersion. For further discussion on hypothermia and frostbite, the following are recommended for additional reading:
NOLS Wilderness First Aid, Tod Schimelphenig and Linda Lindsey.
A Comprehensive Guide to Wilderness & Travel Medicine, Eric A. Weiss, M.D.
Hypothermia, Frostbite & Other Cold Injuries, James A Wilkerson, MD, ed.
Hypothermia - Death by Exposure, William Forgey, MD
