Cold Weather Injuries

When the body is subjected to severely cold temperatures, the blood vessels constrict and body heat is gradually lost. As the body temperature drops, tissues are easily damaged or destroyed.

All cold weather injuries are similar, varying only in the degree of injury to tissues. The extent of injury depends on such factors as wind speed, temperature, type and duration of exposure, and humidity. Freezing of tissue accelerates with wind, humidity, or a combination of the two.

Fatigue, smoking, drugs, alcoholic beverages, emotional stress, dehydration, and the presence of other injuries intensify the harmful effects of the cold. In cold weather, wounds bleed easily because the low temperatures keep the blood from clotting; increased bleeding increases the likelihood of shock.

GENERAL COOLING (HYPOTHERMIA).\ General cooling of the whole body is caused by continued exposure to low or rapidly falling temperatures, cold moisture, snow, or ice. Even though well protected by clothing, a person exposed to low temperatures for an extended period may suffer ill effects because cold temperatures affect the body systems slowly, almost without notice. As the body cools, the casualty goes through several stages of progressive discomfort and disability. The first symptom is shivering, the body's attempt to generate heat by repeated contractions of surface muscles. This is followed by a feeling of listlessness, indifference, and drowsiness. Unconsciousness can follow quickly. Shock becomes evident as the casualty's eyes assume a glassy stare, respiration becomes slow and shallow, and the pulse is weak or absent. As body temperature drops even lower, peripheral circulation decreases, and the extremities become susceptible to freezing. Finally, death results as the core temperature of the body approaches 80F.

To treat hypothermia, take the following steps:

1. Carefully observe respiratory effort and heartbeat; you may have to give CPR during the warming process.

2. Rewarm the casualty as soon as possible. Severe bleeding must be controlled and fractures splinted over clothing before the casualty is moved.

3. Replace wet or frozen clothing and remove anything that constricts the casualty's arms, legs, or fingers, interfering with blood circulation.

4. If the casualty is inside a warm place and is conscious, the most effective method of warming is immersion in a tub of warm water (100F to 105F or 38C to 41C). The water should be warm to the elbow and never hot. Observe closely for signs of respiratory failure and cardiac arrest (rewarming shock).

5. If a tub is not available, apply external heat to both sides of the casualty. Natural body heat (skin to skin) from two rescuers is the best method. This is called "buddy warming." If this is not practical, use hot water bottles or an electric rewarming blanket, but do not place them next to bare skin. Be careful to monitor the temperature of the artificial heat source; the casualty is very susceptible to burn injury. Because casualties are unable to generate adequate body heat, placing them under a blanket or in a sleeping bag is not sufficient treatment.

6. If the casualty is conscious, give warm liquids to drink. Never give alcoholic beverages, or allow the casualty to smoke.

7. Dry the casualty thoroughly if water is used for rewarming.

8. As soon as possible, transfer the casualty to a definitive care facility. Be alert for the signs of respiratory and cardiac arrest during transfer, and keep the casualty warm.

CHILBLAINS.\Chilblains are a mild cold injury caused by prolonged and repeated exposure to air temperatures from just above freezing (32F or 0C) to as high as 60F or 16C. Chilblains are characterized by redness, swelling, tingling, and pain of the skin area. Injuries of this nature require no specific treatment except warming of the affected part, keeping it dry, and preventing further exposure.

IMMERSION FOOT.\Immersion foot, which also may occur in the hands, results from prolonged exposure to wet cold at temperatures ranging from just above freezing to 50F or 10C. It is usually in connection with limited motion of the extremities and water-soaked protective clothing.

Signs and symptoms of immersion foot are tingling and numbness of the affected areas; swelling of the legs, feet, or hands; bluish discoloration of the skin; and painful blisters. Gangrene may occur.

To treat immersion foot, follow these steps:

1. Get the casualty off his/her feet as soon as possible.

2. Remove wet shoes, socks, and gloves to improve circulation.

3. Expose the affected area to warm dry air.

4. Keep the casualty warm.

5. Do not rupture blisters or apply salves and ointments.

6. If the skin is not broken or loose, the injured part may be left exposed; however, if you must transport the casualty, cover the injured area with loosely wrapped fluff bandages of sterile gauze.

7. If the skin is broken, place a sterile sheet under the extremity and gently wrap it to protect the sensitive tissue from pressure and additional injury.

8. Transport the casualty as soon as possible to a medical facility as a litter patient.

FROSTBITE.\Frostbite occurs when ice crystals form in the skin or deeper tissues after exposure to a cold temperature, high altitude, and high-wind speed. The exposure time necessary to produce frostbite varies from a few minutes to several hours. The areas commonly affected are the face and extremities.

The symptoms of frostbite are progressive. Casualties generally incur this injury without being acutely aware of it.. Initially, the affected skin reddens and there is an uncomfortable coldness. With continued heat loss, there is a numbness of the affected area because of reduced circulation. As ice crystals form, the frozen extremity appears white, yellow-white, or mottled blue-white, and is cold, hard, and insensitive to touch or pressure.

Frostbite is classified as superficial or deep, depending on the extent of tissue involvement.

Superficial Frostbite.\In superficial frostbite, the surface of the skin will feel hard, but the underlying tissue will be soft, allowing it to move over bony ridges. This is evidence that only the skin and the region just below it are involved.

To treat superficial frostbite, follow these steps:

1. Take the casualty indoors.

2. Rewarm hands by placing them under the armpit, against the abdomen, or between the legs.

3. Rewarm feet by placing them in the armpit or against the abdomen of a buddy.

4. Gradually rewarm the affected area by warm water immersion, skin to skin contact, or hot water bottles.

5. Never rub a frostbite area.

Deep Frostbite.\In deep frostbite, the freezing reaches into the deep tissue layers. There are ice crystals in the entire thickness or the extremity. The skin will not move over bony ridges and feels hard and solid.

The objectives of treatment are to protect the frozen areas from further injury, to rapidly thaw the affected area, and to be prepared to respond to circulatory or respiratory difficulties.

To treat deep frostbite, follow these steps:

1. Carefully assess and treat any other injuries first. Constantly monitor the casualty's pulse and breathing since respiratory and heart problems can develop rapidly. Administer CPR if necessary.

2. Make no attempt to thaw the frostbitten area if there is a possibility of refreezing. It is better to leave the part frozen until the casualty arrives at a medical facility equipped for long term care. Refreezing of a thawed extremity causes severe and disabling damage.

3. Treat all casualties with injuries to feet or legs as litter patients. When this is not possible, the casualty may walk on the frozen limb, since it has been proved that walking will not lessen the chances of successful treatment as long as the limb has not thawed out.

4. When adequate protection from further cold exposure is available, prepare the casualty for rewarming by removing all constricting clothing such as gloves, boots, and socks. Boots and clothing frozen on the body should be thawed by warm water immersion before removal.

5. Rapidly rewarm frozen areas by immersion in water at 100F to 105F or 38C to 41C. Keep the water warm by adding fresh water, but do not pour it directly on the injured area. Ensure that the frozen area is completely surrounded by water; do not let it rest on the side or bottom of the tub.

6. After rewarming has been completed, pat the area dry with a soft towel. At first, the injured area will feel numb and look mottled blue or purple. Later it will swell, sting, and burn. Blisters may develop and should be protected from breaking. Avoid pressure, rubbing, or constriction of the injured area. Keep the skin dry with sterile dressings and place cotton between the toes and fingers to prevent them from sticking together.

7. Protect the tissue from additional injury and keep it as clean as possible (sterile dressings and linen should be used).

8. Try to improve the general morale and comfort of the casualty by giving hot, stimulating fluids such as tea or coffee. Do not allow the casualty to smoke or use alcoholic beverages while being treated.

9. Transfer the casualty to a medical facility as soon as possible. During transportation, slightly elevate the frostbitten area and keep the casualty and the injured area warm. Do not allow the injured area to be exposed to the cold.