Hypothermia occurs when your core body temperature falls to a level where internal organs cease functioning effectively. As a result, your body loses heat faster than you can produce it. Hypothermia can develop quickly and it can be fatal. Wet, cold, windy weather combined with hard physical effort can lead to exhaustion and leave you vulnerable to hypothermia. Temperatures need not be especially cold for hypothermia to develop; it frequently sets in at temperatures between -2° to 10°C (30°F to 50°F). Field party members should watch out for early warning signs of hypothermia in one another; the buddy system is the most effective way to monitor each other. This is important because victims often do not recognize their own symptoms. You can prevent hypothermia. Be prepared by being well nourished, well rested and properly dressed. Use good judgment and respect safe outdoor procedures.
Hypothermia is a progressive disorder. Mild hypothermia can be treated in the field, but severe hypothermia is life-threatening and extremely difficult to treat in the field. For this reason, it is vitally important to recognize and deal with the early symptoms so that hypothermia does not progress to a severe stage. Early symptoms can be subtle and hard to recognize and no single symptom is diagnostic of hypothermia. Never leave a victim alone as their condition may suddenly deteriorate.
Here is a list of progressive symptoms:
- Feeling chilled and numb is the first symptom. Do not ignore this symptom.
- Loss of focus on the task at hand or a negative attitude toward anything but getting warm indicates mild hypothermia. Be alert for fatigue.
- Loss of fine muscle performance and control, especially in your hands and feet, indicates mild hypothermia.
- A blue or gray pallor develops on your lips and fingertips, depending on your race.
- Uncontrollable shivering; this stops as the victim progresses into severe hypothermia.
- Slurred speech, irrational behavior or the inability to walk or stand all indicate moderate to severe hypothermia.
- A slow, weak pulse that is very hard to measure indicates severe hypothermia. As the heart and lung control centers of the brain cease functioning, unconsciousness and death soon follow.
Take immediate action when you encounter someone suffering from hypothermia. You can treat mild hypothermia in the field. For severe hypothermia, you should stabilize the victim to stop further heat loss and gently transport him or her to a medical facility. Rough handling may cause ventricular fibrillation which often results in death.
- Get the victim into some sort of shelter. If there is no indoor shelter, use whatever is available: a tent, an overturned canoe, a space blanket or tarp to create a tent, branches, rocks or snow for a windbreak. Build a fire as soon as possible. Beware of carbon monoxide poisoning from a heat source in an enclosed space.
- Remove the victim’s wet clothes if possible. A group can share dry clothing to the extent that no other member becomes endangered.
- The ideal way to warm a victim is to place him or her, stripped, in a warmed sleeping bag next to or between one or two other stripped people who are not suffering from hypothermia. Their body heat will warm the victim. You can place warmed objects such as chemical hot-packs, hot water bottles or even heated rocks next to the victim if they are wrapped to prevent burning. Concentrate on warming the trunk, chest and head areas of the victim. Insulate all their extremities (hat, gloves, socks, etc.) to prevent further heat loss.
The following measures will also help treat hypothermia:
- Give warm drinks (without caffeine or alcohol) to a victim who is conscious and not shivering uncontrollably.
- Always handle the victim gently. Do not rub the skin or make the victim perform vigorous exercise; rough handling can cause cardiac problems.
- Seek medical attention as soon as possible; complications frequently develop with hypothermia.
- Severe hypothermia may result in respiration and pulse rates that are undetectable (the pulse may be less than 20 beats per minute and even as low as 1 beat per minute). For this reason, never consider a victim to be dead until he or she is “warmed and dead”.
- STAY WARM
- STAY DRY
- AVOID FATIGUE
Pay strict attention to these tips and you will avoid hypothermia:
- Dress intelligently and appropriately. Wear several layers of loose-fitting clothing with enough space between each layer to entrap 4 mm or 1/4 inch of air. Wool clothing is recommended, as it retains 80% of its insulating qualities even when wet. Down is a good insulator only when it is dry. Always carry waterproof rain gear, preferably the “breathable” kind, as it allows perspiration to escape. Put on rain gear before you get wet for the most effective protection.
- Try to maintain comfortable body temperature. Try not to work up a sweat to avoid wet clothes that may chill you. To cool down, remove your gloves first if your hands won’t be exposed to ice or snow. Next, remove your hat and scarf exposing your neck area. Then loosen the clothing at your wrists and waist. Finally, remove layers of clothing.
- Rest frequently to avoid fatigue. When resting, take shelter from the wind and make certain that you sit on something, such as your pack, to insulate you from the ground or snow. Always stop to make camp before fatigue sets in.
- Your body cannot combat the cold efficiently if you are dehydrated or hungry. Snack often on high-energy foods and drink plenty of fluids. Carry waterproof matches. Then, if necessary, you can make a fire and a hot drink.
- Be on the lookout for symptoms in yourself and others. If you recognize and deal with early symptoms, you can avoid further problems. Always believe the symptoms, not the victim, as he or she may not recognize them.
- Learn to recognize weather conditions that may cause hypothermia. Be prepared for them.
- Beware of wind chill. The cooling effect of wind on your body can be enormous. Use windproof clothing and if necessary, take shelter from the wind.
Frostbiteoccurs when your body tissue actually freezes. It most commonly affects the toes, fingers, ears, nose, or face. Hypothermia and frostbite often develop at the same time and wind chill is frequently a contributing factor. Use the buddy system to watch for signs of frostbite in yourself and other members of your field party. Superficial frostbite may be treated in the field, but deep frostbite should be treated at a medical facility.
- White or gray patchy skin develops on the face, fingers and/or toes.
- Pain in these extremities is present, but it gradually disappears as frostbite develops.
- Skin does not move easily over the knuckles or toes; it becomes hard and waxy.
- Never thaw frostbitten tissue if it is likely to refreeze as this causes permanent tissue damage. Move the victim to a medical facility.
- Do not rub affected areas with anything. Never thaw with direct heat (e.g., fire, heating pad, chemical hot-packs).
- Thaw the affected area rapidly in a tub of warm water 40°-42°C or 100°-110°F. This temperature is important. Suspend the affected limb in the water so that it does not touch the sides. If the ears or face are affected and cannot be submerged, use hot compresses maintained at this temperature. This procedure is painful.
- Protect the thawed areas with sterile dressings and keep the victim warm to promote good circulation.
- Do NOT break the blisters that may form.
- Seek medical attention as soon as possible.
- Stay warm and stay dry. Many precautions that you take to prevent hypothermia apply to frostbite.
- Recognize the importance of wind chill on exposed flesh in freezing temperatures.
- Pay attention to those areas of your body that may be exposed to the cold. Dress accordingly. A balaclava or face mask will protect your face better than a hat alone. Avoid clothing such as tight boots and gloves that might restrict your circulation.
- Wear gloves when handling volatile fuels as these products may cause immediate frostbite if they come in contact with your bare skin. Cold metal surfaces can do the same.