Temperature Induced Stress - Cold Exposure
Part 1 of 2
T.R. Consulting, Inc.
January 2003 Safety Article
Written and compiled by:
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This month’s article is the first of a two part series discussing temperature induced stress. To access the second part of this series about heat stress, go to http://www.trconsultinggroup.com/safety/feb2003.html.
Exposure to very cold temperatures for extended periods of time can lead to either (or both) frostbite or hypothermia. Frostbite is tissue damage that develops in varying degrees depending upon the duration of the skin exposure, the temperature of exposure and the ratio of skin surface area to mass of the exposed skin. Hypothermia results when the body core temperature falls below 95 degrees Fahrenheit. Frostbite can be a severe injury depending upon the degree of frostbite encountered. Hypothermia should be considered a medical emergency and anyone suspected of suffering from it should get medical attention as soon as possible.
Exposure to temperatures below 32 degrees Fahrenheit can cause frostbite. Several degrees of severity are associated with the resultant tissue damage. Incipient frostbite (also termed as “frost nip”) is the mildest form of frostbite. Incipient frostbite affects only the tissue at or near the surface of the skin. Progressively, frostbite works its way deeper into the skin. So long as the frostbite does not affect the blood vessels, recovery is generally complete. In the case of deep frostbite affecting the blood vessels, glucose and oxygen transport to the affected region discontinue and cell death results. Cell death can lead to gangrene, which can necessitate the amputation of the affected tissue or even an extremity. In all cases, deep frostbite causes permanent damage.
Any part of the body can be affected by frostbite, but the areas of the body with the highest ratio of surface area to mass are the most susceptible. These most susceptible areas are the ears, the nose, the fingers and the toes. Proper covering of the skin will prevent frostbite. Constriction of the blood flow to the extremities can cause greater susceptibility to frostbite. Items that can cause constriction of blood flow include rings, watches and tight fitting shoes (especially when wearing several layers or thick socks).
Several environmental factors can increase the susceptibility to frostbite as well. Frostbite progresses more rapidly at lower temperatures. The greater the velocity of the wind (wind chill), the more quickly heat is removed from exposed regions of skin. Finally, snow coming in contact with exposed skin will initially turn to water. This formation of water on exposed skin can leach heat from the skin and increase the rate of tissue damage.
Symptoms of Exposure
The earliest sign of frostbite is a sensation of pins and needles, followed by numbness and eventually complete numbness. The skin appears white and feels cool, but resilient underneath at first. This is followed by white skin that is cold and hard. Finally, the skin will become red and swollen. Skin that has frozen will form blisters upon thawing and some areas of skin may appear black, indicating that the tissue has died.
Important Note: when frostbite is accompanied by hypothermia, the hypothermic condition must be treated first and medical attention must be promptly sought. Conditions requiring first aid should be attended to immediately.
DO shelter the victim from the cold
DO remove clothing from the affected region
DO remove articles such as watches and rings that can restrict blood flow
DO rewarm the affected area by covering with warm hands or clothing
DO immerse affected parts in warm (less than 110 degrees Fahrenheit) water, if available
DO cover treated areas with sterile dressings
The armpits are a good source of warmth for warming frostbitten extremities. The victims hands can be placed under the armpits to warm. The person providing on site treatment can use his or her armpits to warm a victim’s feet.
FROSTBITE DO NOTs
DO NOT rub or message the affected body parts
DO NOT use direct heat to warm affected body parts
DO NOT promote movement of the affected body parts
DO NOT allow frostbite victims to walk on frostbitten feet
DO NOT attempt to burst blisters that form during thawing
Prolonged exposure to extremely low weather conditions, immersion in cold water (rivers, lakes, oceans), and wearing wet or damp clothing in cold conditions can lead to hypothermia (also referred to as systemic hypothermia). The very young and the very old are the most susceptible to the development of hypothermia due to a decreased (or incompletely developed) ability to compensate for body temperature loss. When exposures cause the body’s temperature to fall below 95 degrees Fahrenheit, the person is considered to be suffering from hypothermia. Hypothermia is most accurately diagnosed by measurement of the body temperature rectally.
A person suffering from even mild hypothermia will have a slowed heart rate and usually will exhibit drowsiness and confusion. Characteristically, the skin will be pale and the face will appear puffy. Areas of the skin that are normally warm to the touch, such as the armpits, will be cold. In the case of severe hypothermia, the depth and rate of breathing will change. The victim will breathe more slowly and take more shallow breaths. The victim’s muscles may become stiff and loss of consciousness is possible. In the most severe cases (where the core body temperature falls below 90 degrees Fahrenheit), the heart may beat only faintly, the heartbeat may become irregular, or the heart may stop altogether.
In the most mild cases of hypothermia, removing the victim from the cold, removing any wet or damp clothing, covering the head and shoulders and providing the conscious victim warm (not hot) liquids may be sufficient to induce recovery. Even in these types of cases, the victim should receive medical attention. In more severe cases, a young and otherwise healthy individual can be warmed in a warm bath (not too hot though). Infants and the elderly can suffer adverse health effects from immersion in warm water. This is especially true in the elderly where such treatment could result in a lowered flow of blood to the heart and brain by increasing the blood flow to the surface of the body.
DO seek medical help for those suspected or known to be hypothermic
DO begin CPR if the victim is not breathing
DO move the victim to a warm place
DO take off wet clothing, re covering the victim with dry covers (water-proof where necessary)
DO provide warm beverages (not hot) to conscious victims (you may need to help steady the cup)
DO allow younger and otherwise healthy individuals to warm in a tub with warm (not hot) water.
Hypothermia DO NOTs
DO NOT message or rub the victims skin
DO NOT provide beverages to unconscious victims
DO NOT give alcohol to victims
DO NOT warm the victim using direct heat sources
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