Winter is coming, and many places have already begun to experience their share of cold weather. Whether in good times or in survival settings, family medics should know about the effects of freezing temperatures on the human body, and what to do if they come upon a victim of hypothermia.
Hypothermia is a medical emergency that occurs when body temperature drops below 95° Fahrenheit (35° Celsius). It occurs as a result of prolonged exposure to cold and can be life-threatening.
Normally, the body core ranges from 97.5 to 99.5 degrees Fahrenheit (36.5-37.5 degrees Celsius) when taken orally or rectally. Rectal temps tend to be slightly higher (about 0.5 degrees Fahrenheit) than oral, and oral temps are slightly higher than skin readings, such as those taken in the armpit.
HOW THE BODY LOSES HEAT
The body loses heat in various ways:
Evaporation – Perspiration (sweating) from physical exertion or other reasons releases heat from the body core. This is helpful in summer heat but dangerous in the cold.
Radiation – The body loses heat to the environment when the ambient (surrounding) temperature is below the core temperature. For example, you lose more heat if exposed to an outside temperature of 20 degrees F than if exposed to 80 degrees F.
Conduction – The body loses heat when its surface is in direct contact with cold temperatures, as in the case of someone falling from a boat into frigid water (think “Titanic”). Water, being denser than air, removes heat from the body much faster.
Convection – Heat loss where, for instance, a cooler force is in motion against the body core. The air next to the skin is warmer than the surrounding area and is lost when exposed to wind. This requires the body to use energy to re-heat. Wind Chill is one example of air convection: If the ambient temperature is 32 degrees Fahrenheit but the wind chill factor is at 15 degrees, the body loses heat as if it were actually 15 degrees.
DIAGNOSING HYPOTHERMIA
When exposed to cold, the human body kicks into action to produce heat. It does this by muscle action known as shivering. Muscles shiver to produce heat, and are a clear warning that you need to warm up.
As hypothermia worsens, more symptoms will become apparent. Aside from shivering, the most noticeable symptoms of hypothermia will be related to mental status. The person may appear confused, uncoordinated, and lethargic. The victim’s speech becomes slurred and they often will appear uninterested in helping themselves.
Look for what are called the “-Umbles“ – stumbles, mumbles, fumbles, and grumbles. These represent changes in motor coordination and levels of consciousness seen in hypothermia.
All this occurs due to the effect of cooling temperatures on the brain; the colder the body core gets, the slower the brain works. Other organs then begin to shut down, and the victim eventually loses consciousness. Any unconscious person you find exposed to cold weather is hypothermic until proven otherwise.
Cold-related tissue effects can cause local damage, such as frostbite. Frostbite affects areas like fingers, toes, nose, earlobes, and even lips. Sometimes called “Frostnip” or “Chilblains” in early stages, it begins as numbness, pins and needles sensations, and redness. Blistering may occur.
If not warmed in time, the skin turns progressively white and waxy, then blue, and, finally, black, a condition known as “gangrene.” Gangrenous tissue is dead and unsalvageable in survival settings. Victims with gangrene may require debridement (the removal of dead tissue) or even amputation.
We’ll discuss this further in part 2 of this series. For now, let’s stick to general hypothermia.
Treating Hypothermia
Failure to act quickly to treat hypothermia may lead to organ failure and death. Important measures to take are:
Get the person out of the cold. Transport to a warm, dry location. If you’re unable to move the person out of the cold, shield them as much as possible. Be sure to place a barrier between them and the cold ground.
Monitor breathing. A person with severe hypothermia may be unconscious. Verify that the patient is breathing and check for a pulse. Begin CPR if necessary.
Take off wet clothing. If the victim is wearing wet clothing, remove them gently. Cover the person with layers of dry blankets, including the head, but leave the face clear.
Share body heat. To warm the person’s body, remove your clothing and lie next to the person, making skin-to-skin contact. Then, cover both of your bodies with blankets. Some people may cringe at this notion, but it’s important to remember that you are trying to save a life. Gentle massage or rubbing may be helpful, but may be traumatic.
Give warm oral fluids. If (and only if) the affected person is alert and able to swallow, provide a warm, nonalcoholic, non-caffeinated beverage to help warm the body. Alcohol does not warm you up; instead, it expands blood vessels and actually hastens the loss of heat from the body core.
Use warm, dry compresses. Use a first-aid warm compress or a makeshift compress of warm (not hot) water in a plastic bottle. Apply compresses to the neck, armpit, and groin. These areas will transport heat to the body core effectively. Some military studies suggest warming the hands and feet is also useful.
Avoid applying direct heat to skin. Don’t use hot water, a heating pad or a heating lamp directly on the victim. The extreme heat can damage the skin, cause strain on the heart, or even lead to cardiac arrest.
PREVENTING HYPOTHERMIA
An ounce of prevention is worth a pound of cure, and many cases of hypothermia can be prevented.
The environment plays a large role in your success as medic in survival settings. If you don’t take weather conditions and other factors into account, you have made the environment your enemy.
On the road, it’s imperative to anticipate the climate through which you’ll be traveling. This includes being properly dressed for wind conditions and wet weather.
Travel with a partner or a group if at all possible and make certain all are physically fit for the challenge. Pack enough food, water, and a way to produce heat.
C.O.L,D.
For the prevention of hypothermia, remember the simple acronym C.O.L.D. This stands for: Cover, Overexertion, Layers, and Dry.
Cover. Dress appropriately for the conditions. A surprising amount of warmth is lost from the head, so be sure to wear a hat. Instead of using gloves to cover your hands, use mittens. Mittens are more helpful than gloves because they keep your fingers in contact with one another, conserving heat.
Overexertion. Avoid activities that cause you to sweat. Cold weather causes you to lose body heat quickly; wet, sweaty clothing accelerates the process. Rest when necessary and use rest periods to self-assess for cold-related changes. Pay special attention to the status of your elderly or juvenile group members. Diabetics are also at high risk.
Layers. Layers of loose-fitting, lightweight clothing do the best job of insulating you against the cold. Use tightly woven, water-repellent material for wind protection. Wool or silk inner layers hold body heat better than cotton does. Some synthetic materials, like PrimaLoft, Thinsulate, and Thermolite are used to great effect in staying warm. Time-honored waterproof materials like Gore-Tex work well also.
Dry. Keep as dry as you can. Get out of wet clothing as soon as possible. It’s very easy for snow to get into gloves and boots, so pay particular attention to your hands and feet.
You might be concerned about how to tell hypothermia in your snow-loving, four-legged best friend. Find out about hypothermia in dogs in this article:
Hypothermia In Dogs
Joe Alton MD
dr.bones and nurse amy
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