Hypothermia – A Cold Hearted Killer

Disclaimer:  Hypothermia is a life threatening condition that can deteriorate rapidly if treated improperly. You should seek to become well versed in its detection and treatment, and always get the assistance of trained medical personnel where available. 911 is your friend. This article is in no way meant to train anyone in treating victims of hypothermia. However, it is possible that one may wind up in a situation where self treatment, or even assistance to another, is only possible with whatever knowledge, skills and materials are immediately available. Where there is no help, you are on your own.

What is Hypothermia?

Hypothermia is the lowering of the body’s “core” temperature to below 95 degrees. The human body has a nominal normal temperature of 98.6 degrees. It will try to maintain this temperature through warming in cold environments (shivering), and via cooling in warm (sweating). Blood flow is progressively reduced to the extremities – the hands and feet, then the arms and legs. The majority of the blood supply is restricted to circulating through the core to keep the blood warm, and the internal organs alive and functioning as close to normal as possible. It is a battle to prevent body heat from dissipating faster than it can be regenerated.

The initial mechanism the body uses to combat heat loss is shivering. Muscles contract and relax quickly. In doing this, they burn fuel – sugars and fats stored in the body – which releases heat as a byproduct.

Following on this is a restriction of blood flow to the extremities. Arms and legs have a large surface area in relation to their mass, so they lose heat faster than the torso. Preventing this loss retains some heat within the core. It is a wonderful natural response to an unhealthy situation, but the battle is fought on a thin line. Just a few degrees too cold, and internal organs lose the ability to operate as they should. The head is also an area of large heat loss, which needs to be well covered in cold environments.

 

Risk Factors

The young and the elderly are at high risk, because their ability to regulate temperature is less robust than in healthy adults. Old age decreases the ability to sense temperature accurately, so the body makes improper adjustments. Very young people lose heat faster than older larger people due to surface area /body mass ratios. For both of them, air conditioning set too low can bring on hypothermia.

Wet clothing pulls heat away from the body up to 25 times faster than air alone. Someone that is dumped off a rafting trip into the water, even on a warm day, can experience hypothermia. A body in cold water stands a better chance of surviving if it remains dressed, since even saturated clothing can traps some heat. Moving around rapidly in the water can make a person feel warmer, but it really “washes” away more heat and the water warmed by the skin is removed, and replaced with the next batch of cold water.

Cold moist air currents, such as a moving mist or fog, will wet the clothing. As body heat evaporates the water, or bleeds heat through it into the air, a rapid chill can come on. With moving air, the wind chill factor comes into play and drops temperatures faster.

Alcohol and drug use increase the risks by affecting internal temperature regulation. Alcohol flushes the skin with warm blood, making the victim “feel” warmer, but as that blood then cools, their overall temperature drops and they are worse off.

Anorexia nervosa, stroke, diabetes are all conditions that affect circulation or circulatory controls. Even if healthy otherwise, these people can deteriorate faster than others when under the wrong conditions.

Respiratory heat loss can account for 10% – 30% the body’s heat loss by cooling the core. For some, just being in cold still air, even wrapped up, is a risk.

People that have lost blood concurrently with hypothermic conditions have elevated risk factors. With less blood in their core, they can not warm as well, and will potentially suffer from elevated heart rates required to keep blood pressure up. This will further stress the heart.

 

Symptoms

Infants – bright red and cold skin, and very low energy. They are at the greatest risk since they can not complain about the cold, and can become lethargic very quickly.

Mild 98.6 – 96

  • Shivering
  • Alert, but distracted
  • Still able to walk and talk
  • Difficulty with fine motor skills such as closing a zipper or working buttons
  • Progressing, they can be irritable, confused or apathetic

Moderate hypothermia 95 – 93

  • Deteriorating condition can worsen rapidly
  • Uncontrollable shivering
  • Mental alertness suffers severely
  • Slurred or difficult speech
  • Ataxia – hard time walking upright or straight. Reduced blood flow to the extremities lessens coordination and, mixed with reduced motor skill control within the brain and general lethargy, results in this visible indicator.
  • Denial of condition, combative, poor decisions, confusion, memory loss
  • May try to remove clothing, risking even quicker heat loss
  • Desire to be left alone and even to go to sleep (Do NOT allow sleep)

Severe 92 – 86

  • Shivering stops, or becomes waves of violent shivering followed by pauses
  • No coordination
  • Cannot walk, may collapse into fetal position
  • Shallow and slow breath, slow heart rate
  • Dilated pupils
  • Unconsciousness
  • Pale cold skin

 

Treatment

General treament.

Anything that comes into contact with the victim must be dry, warm, or inherently warm, such as in the case of wool blankets and quality sleeping bag interiors. Active warming devices are for use on the core body area only, except in mild cases, wherein a warm bath can be helpful.

Do not move a patient roughly or quickly, and this includes the traditional TV treatment methodology of briskly rubbing a victim’s arms, legs and body and shaking them up doing so. When the extremities slow blood flow to preserve heat in the core, they pool an amount of blood. This blood cools, and also becomes somewhat toxic in that it has built up the byproducts of life and has not been filtered through the core. Rapid motion, jostling and rubbing can force this cold, toxic blood out of the extremities and into the core, where it will assault the heart and lungs. This cold blood can kill. Rewarming must be done gradually. In cases worse than mild hypothermia, a warm bath can cause the release of this cold blood into the core where the heart can undergo severe shock. Death is likely in that case.

Warm sugary drinks, tea, and fatty foods like chocolate can help with the “internal furnace”. Be sure to ask if the victim can cough first, or they might not be able to swallow.

As said in http://www.voanews.com, “members of search and rescue teams have a saying that hypothermia victims are not dead until they are warm and dead.” Rewarming is a must, and gradual rewarming is just as important. Victims of severe hypothermia can have such a slow heart beat and respiration rate that they appear dead. Don’t give up on them, but don’t be panicked or ignorant, either.

Mild 98.6 – 96

Treatable in the field

Isolate the victim from the cold. Remove wet clothing and replace with dry clothing or coverings. Have them sit up on a chair or other stand, insulated from the cold ground. They should be wrapped in dry clothing or other coverings and secured against cold air, or movement of air. The earth can be insulated with bedding, branches, sleeping mats, carpet… anything to prevent the cold earth from drawing heat away from the tee-pee of covering you build around the victim. To block the wind, you can build a lean-to, arrange a windbreak with a tarp, or by using terrain features. By ensuring the victim is in warm dry wrappings, isolated from cold air currents and the ground, his internal body temperature can rise on its own. This is called passive rewarming.

The victim can also benefit from treatments used for moderate and severe cases wherein chemical heating pads, hot water bottles or similar items are used. These are placed in the groin, armpits, back of the neck and on the torso in order to transfer heat to the core.

Give the victim warm sugary drinks, or fatty treats like chocolate. Warm water at a minimum, helps, to prevent dehydration and to internally warm the core.

Be sure the head is covered. This is often overlooked. Major heat loss through all areas of the head is possible, and defeats the other efforts at core warming.

After caloric intake, if the victim is warming up and the shivering has stopped, he can be encouraged to move around a bit, slowly. This will help mild cases warm faster in a natural way.

Moderate 95 -93

Active rewarming followed by passive.

The skin is placed in contact with something warm. Hot water bottle, chemical hand or body warmers, another warm body, clothing and blankets warmed by fire or other means. Warm packs in the groin, armpits, neck and trunk. If  possible, you can use an electric blanket under the torso.

Heart muscle can be irritated by the cold and forced into arrhythmia. Discourage active motion and exercise in these cases. The danger of cold shock to the heart via blood coming in from the extremities is too high.

Severe 92 – 86

Requires hospitalization.

Active internal rewarming within a hospital. Heart bypass including warming the blood, heated breathing apparatus, fluid replacement. The heated air can be between 107 and 122 degrees. The brain stem, at the base of the skull, can be rewarmed externally, which may help the body adjust more efficiently and improve the level of consciousness and responsiveness.

The best treatment for this is prevention. Be aware of growing symptoms and act quickly.

 

Prevention

Layered loose clothing traps warm air near the skin and within the clothing itself. Some fibers of clothing are better at this than others. Wool and nylon garments are good insulators. Cotton, though, is a horrible choice, as the fibers collapse when wet, and work overtime to draw heat away from any surface they touch. Any clothing that feels cold when wet, or traps moisture on the skin, is dangerous. The individual layers can be removed as temperatures change. In cold environments, sweating in warm clothes can produce a shock chill. In freezing environments, it can freeze and produce frostbite and hypothermia. Layering helps prevent this. It can apply to all articles, including pants and socks.

Mittens are better than gloves for retaining heat within the hands and fingers. Individual fingers can not warm efficiently within the generally insufficiently insulated tubes that make up glove fingers. Just as bodies share heat, so do fingers.

Keep your head covered, especially if you are shaved, or have short hair.

Keep a watch on yourself and others. Look for the signs: shivering, complaints of being very cold, cold skin, muscle control issues, blank looks and slow responses to questions – any signs of cold accompanied by lethargic responses and changes in behavior.

In all cases:

NO alcohol or caffeinated beverages since these lead to loss of vascular control and dehydration

Resources referenced in this article include, but are not limited to:

 

 

 

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