Hypothermia occurs, when the body temperature does not exceed 35°C (95 F). It may be light (32-35°C) (90-95 F), moderate (28-32°C) (82-90 F) or severe (less than 28°C) (82 F). The body temperature of warm-blooded animal, including human, is maintained at approximately constant level due to biological homeostasis. However, when the body is exposed to cold, the internal mechanisms are not be able to replenish the heat loss.
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In case of hypothermia, vital activity decreases, that leads to a decrease in oxygen demand. This fact is used in medical practice, when they use artificial local or general hypothermia. Local hypothermia is used in the treatment of bleeding injury and inflammation. The total body hypothermia is used in heart surgery, in the treatment of traumatic brain injury, intracranial hemorrhages. Hypothermia is the opposite of hyperthermia, which leads to heat stroke.
Causes of hypothermia
The causes of hypothermia are varied and are usually several of them. The true cause of hypothermia is difficult to define, because it is not always clear.
Symptoms of hypothermia
Overcooling of the human body, which is called hypothermia is the result of its location in a cold environment, sometimes with the fatal end. During the first moments at the cold, a human reflex increases body temperature and pulse quickens. Then, the body resist to heat loss ans there is a strain of superficial blood vessels. The person feels an increasingly strong chills, stimulating the heat. Even at this stage it may lead to “intercept” of the breathing and death may occur due to so-called “cold shock” because of the body’s response to a sudden change in the external environment. During further cooling, there are painful muscle cramps. Once the body temperature drops to about 35°C (95 F) (when the body is no longer able to maintain or reproduce heat), it begins to decrease rapidly.
There are another symptoms:
- lost of sensitivity to pain,
- impaired coordination,
- general weakness, and indifference to the fate.
At body temperature about 32-33°C (90 F):
- disturbed peripheral and then the central blood circulation;
- pulse becomes weak;
- due to circulatory disorders of the brain there are significant mental and breathing disorders;
- clouded consciousness;
- people lose a will
With a drop in temperature to 30°C (86 F) man falls into unconsciousness;
there is cardiac arrhythmia and other irreversible processes in the body.
Death occurs in most cases at the body temperature 25°C (77 F).
How to treat hypothermia
try to call emergency medical care,
move the victim to a warm place,
cover with warm blanket
check breathing and pulse
give a hot drink.
A common first aid to an unconscious person:
airway clearance,
rescue breathing,
stimulate circulation.
Increase the temperature of the environment: place a person in a warm bath or a warm shower with water 38-40°C (104 F), and possibly – in the sauna. Some doctors advise to place in warm water only a torso and leave limbs outside to warm important organs in the first place and to reduce the blood flow to the extremities. But there are many who are against warm baths, arguing that such warming of the skin will lead to the expansion of peripheral blood vessels and to blood flow from the internal organs: warming the skin, we cool the interior organs, enhancing hypothermia. Therefore it is better not to take a hot shower or bath after exposure to cold, but allow the body to gradually warm through internal resources.
The body is able to stop the drop in temperature and to increase it by producing heat energy by:
active movements,
restriction of blood flow to the skin,
improved metabolism due, for example, power-calorie food.
Alcohol has at first a positive effect on the condition of the victim, but then it exacerbates hypothermia.
Wrap a person in a warm blanket, cloth, paper or anything, just to reduce the heat loss of the body in contact with the air. Close physical contact with another person is an effective way to eliminate the effects of hypothermia.