First aid: Hypothermia

Under most conditions your body maintains a healthy temperature. However, when exposed to cold temperatures, especially with a high wind chill factor and high humidity, or to a cool, damp environment for prolonged periods, your body's control mechanisms may fail to keep your body temperature normal. When more heat is lost than your body can generate, hypothermia, defined as an internal body temperature less than 95 F (35 C), can result.

Wet or inadequate clothing, falling into cold water and even not covering your head during cold weather can increase your chances of hypothermia.

Signs and symptoms include:

• Shivering
• Slurred speech
• Abnormally slow breathing
• Cold, pale skin
• Loss of coordination
• Fatigue, lethargy or apathy
• Confusion or memory loss
• Bright red, cold skin (infants)

Signs and symptoms usually develop slowly. People with hypothermia typically experience gradual loss of mental acuity and physical ability, so they may be unaware that they need emergency medical treatment.

Older adults, infants, young children and people who are very lean are at particular risk. Other people at higher risk of hypothermia include those whose judgment may be impaired by mental illness or Alzheimer's disease and people who are intoxicated, homeless or caught in cold weather because their vehicles have broken down. Other conditions that may predispose people to hypothermia are malnutrition, cardiovascular disease and an underactive thyroid (hypothyroidism).

To care for someone with hypothermia:

• Call 911 or emergency medical assistance. While waiting for help to arrive, monitor the person's breathing. If breathing stops or seems dangerously slow or shallow, begin cardiopulmonary resuscitation (CPR) immediately.
• Move the person out of the cold. If going indoors isn't possible, protect the person from the wind, cover his or her head, and insulate his or her body from the cold ground.
• Remove wet clothing. Replace wet things with a warm, dry covering.
• Don't apply direct heat. Don't use hot water, a heating pad or a heating lamp to warm the victim. Instead, apply warm compresses to the center of the body — head, neck, chest wall and groin. Don't attempt to warm the arms and legs. Heat applied to the arms and legs forces cold blood back toward the heart, lungs and brain, causing the core body temperature to drop. This can be fatal.
• Don't give the person alcohol. Offer warm nonalcoholic drinks, unless the person is vomiting.
• Don't massage or rub the person. Handle people with hypothermia gently; their skin may be frostbitten, and rubbing frostbitten tissue can cause severe damage.

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• Hypothermia