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Winter Cold Injuries

While riding your local trails this winter, you come across a cyclist fumbling with his jacket zipper and complaining of pain in his hands. When you remove his gloves, you find cool, red fingers with no swelling. His exposed face and nose is also red and cool. You are a 90 minute ride from the trailhead. What do you do next?

This winter as the temperature drops and the snow begins to fly, many trail users will continue to enjoy their favorite areas despite extreme conditions. Winter riding exposes the cyclist to certain threats not encountered during warm seasons. Two of the most common are frostbite and hypothermia. Both are fairly common in the winter months.

Frostbite

Frostbite is a localized injury caused by exposure to a cold environment. Frostbite can be classified similar to burns: simply as either superficial (first or second degree) or deep (third or fourth degree).

Signs and Symptoms

Frostbite can occur on any skin surface. The most common locations are the nose, ears, face, hands, toes and feet.

First Degree Frostbite (mild)

  • Stinging or burning sensation in affected area.
  • Red, cool skin
  • Mild swelling

Second Degree Frostbite (moderate)

  • Numbness in area
  • Possible decrease in pain
  • Severe swelling
  • Skin is hard and waxy to touch
  • Blisters may form

Third/Fourth Degree Frostbite (severe)

  • Patient may experience "block of wood" sensations
  • Deep, aching pain
  • Skin is blue/gray and solid to the touch
  • Blood blisters may form

Field Treatment

Remove all wet and constrictive clothing involving the affected body part. Elevate and wrap in loose, dry clothing or bandages. Separating the fingers or toes with bandages is also advantageous. Splinting the extremity may be comfortable for the patient. For moderate and severe cases, the patient should be evacuated immediately to a hospital for further management and monitoring. Thus rapid transport, ideally within 2 hours, is the treatment of choice for frostbite.

If evacuation and transport are available but a prolonged time is anticipated, there are several options. One option is rapid rewarming in the field followed by prevention of refreezing. However this must be approached with great caution. This should only be performed by those with proper training and in extreme circumstances. It is particularly dangerous for the involved extremity to be repetitively frozen and unfrozen. This can cause further tissue damage. One should only initiate the rewarming process if evacuation and transport have been arranged and if refreezing of the body part is not likely. Another option is to leave the affected body part frozen until advanced medical care is available.

Further precautions include not warming the extremity with dry air such as fires or heaters, since the air can cause excessive drying or further thermal injury to already damaged tissues. One should also avoid friction, such as rubbing one's hands together or rubbing snow over the involved extremity to stimulate circulation. Additionally, do not drain any blisters in the field as these could become infected.

Hypothermia

Hypothermia is another common cold injury. This condition is defined as a core body temperature of less than 95 degrees Fahrenheit. Threats from hypothermia range from mild to life-threatening. Winter trail users are at risk for several reasons:

  1. Direct, prolonged exposure to cold conditions.
  2. Exposure to wind.
  3. Accelerated loss of heat from heavy breathing during exercise.

Physical Findings

Almost everyone who has spent time in the winter outdoors has experienced some of the signs and symptoms of mild hypothermia. If treated properly in the field, the symptoms will rarely degenerate into life-threatening severe hypothermia.

As the body's temperature falls and hypothermia becomes more severe, body functions begin to slow down. Shivering stops. Circulation slows. Irregular heart beats (arrythmias) can occur. The patient can become confused, lethargic, disoriented and eventually comatose.

Signs and Symptoms

Mild Hypothermia

  • Patient has the "umbles" - fumbles, stumbles, bumbles
  • Difficulty with fine motor skills (may have difficulty zipping clothes)
  • Shivering
  • Skin may be flushed and cold to the touch.

Moderate Hypothermia

  • Violent shivering
  • Loss of coordination
  • Difficulty speaking
  • Slow thinking and mild confusion

Severe Hypothermia

  • Shivering stops. Muscles become stiff.
  • Diminishing level of consciousness.
  • Patient may be disoriented, confused or irritable.
  • Inability to stand or walk.
  • Skin is blue or puffy.

Treatment

Most mild cases of hypothermia should be treated in the field. Initial steps include:

  1. Remove the patient from the cold environment.
  2. Remove wet clothing.
  3. Encourage shivering and exercise.
  4. Give food or warm drinks if available.
  5. Warm the patient with dry clothing and external heat packs.

Severe cases of hypothermia are a life-threatening emergency and require immediate evacuation to advanced medical care. Do not attempt to move or rewarm a severely hypothermic patient in the field. Arrange for transport to a hospital where advanced warming techniques can be initiated.

Wrap-up and Prevention

For those of us venturing into a winter environment, frostbite and hypothermia are preventable since this injury is usually a direct a result of our inability to protect ourselves from cold conditions. The most important prevention of cold injuries is good leadership and judgment when pursuing outdoor activities. Proper selection and use of equipment is also essential. Additionally, the following measures are methods to minimize the risk and impact of frostbite this winter:

  1. Dress appropriately to maximize body warmth.
  2. Avoid perspiration, which will evaporate and produce further chilling
  3. Keep hands and feet dry. Moist or wet hands and feet lower the body's resistance to cold.
  4. Avoid constrictive clothing since blood flow can be reduced.
  5. Avoid alcohol and tobacco, which decrease blood flow to the extremities.
  6. Eat a lot. Caloric requirements increase in cold conditions.
  7. Maintain appropriate hydration.
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