Frostbite, classifications and how to avoid it in the mountains: recommendations from the mountain guides of the French university, STAPS.
In the mountains, a person is exposed to several factors that cause them to fight the cold. Violation of heat exchange may occur due to weather conditions, improperly chosen clothing or incorrect behavior. Each body radiates and loses heat due to infrared radiation. This is what my blog is about today.
A few reasons and ways to combat the cold:
The body cools down from the bottom, but the heat comes from above (“if you have cold feet, put on a hat”).
Evaporation of a drop of water consumes calories. Sweating does not cool the body if there is no evaporation.
“Stay dry = stay alive”
The intensity of air cooling increases with the speed of the wind (“always protect yourself from the wind”).
The higher – the cooler. Rising every 100m, the temperature around drops around 0.6°C. Do not wait until it freezes.
Isothermal point in air: 25°C
Isothermal point in water: 37°C
Temperature is the balance between thermolysis (heat loss) and thermogenesis (a reaction that produces heat in response to physical exercise and thrills). A person must maintain a temperature of about 37°C. It is this temperature that the main organs require – the brain, the heart, the large vessels, in order to function properly.
The most frequent consequence of the effects of cold is frostbite. It can trigger Raynaud’s syndrome – a circulatory disorder that leads to numbness or pain in the limbs. This vasospastic disease occurs in 3-5% of the population, and in women 5 times more often than in men.
A more serious consequence is necrosis (or necrosis) – a pathological process, expressed in the death of tissue in a living organism as a result of any exo-or endogenous damage to it. This disease often affects professional skiers because of the compression of the 5th and 1st metatarsal in the ski boot. Healing is very slow and requires the imposition of special dressings.
Not to be confused with the pathology of the moon shoe (pathologie de la Moon boot). It occurs at positive temperatures in a humid environment. Due to terminology confused with frostbite.
The main cause of frostbite is cold aggression. This freezing of the tissue is due to more or less prolonged exposure to temperatures below 0°C.
The clinical aspect is close to a burn, but the physiopathological mechanisms and therapeutic approaches are different.
Frostbite most often affects the fingers or toes, face, nose and/or ears. Symptoms include a period of discomfort with numbness of the extremities, and then the absence of signs of pain. Thus, beware if the person who complained about the cold is still exposed to it, but no longer complains of pain. When warming occurs painful tingling happens in the affected area and the skin in the area of frostbite becomes white.
There are three phases of frostbite: primary (cooling), secondary (numbness) and the last phase of irreversible lesions.
But what happens during frostbite?
Frostbite is the interruption of blood circulation in the limbs by closing the blood vessels – this is what is called in medicine acute ischemia by vasoconstriction caused by cold. Under the influence of cold, in order to protect vital organs and reduce the flow of cold blood to them (and their temperature, as already noted, must be maintained at 37°C), precapillary sphincters are closed. At the same time, arteriovenous shunts are opening. This leads to the oxygenation of peripheral tissues. Thus, oxygen-containing blood does not reach the extremities, cells suffer from a lack of oxygen and die.
Progressive necrosis has many symptoms such as limbs turning gray, blue or purple. After getting into heat, the initial lesion persists for 12-24 hours. Then in 24-48 hours bubbles appear. Sometimes they are filled with blood. This phase aggravates the initial damage: the vessel wall is damaged and our body tries to seal the damage. In cases of severe frostbite, the mechanisms created to seal the damage are so active that they cause blockages in the blood vessels.
In 48-72 hours, the final and irreversible damage occurs in heat: dry gangrene of the devitalized tissues occurs.
If treatment is started on time, amputation can be avoided. However, patients with severe frostbite, even if they managed to avoid amputation, often suffer from early osteoarthritis (from 6 months to 1 year). This osteoarthritis can sometimes cause early deformity of the interphalangeal joints.
Classification of frostbite:
Determination of the degree of the initial lesion (stage) is carried out after getting into heat.
There are 4 stages:
1. Lack of injury after warming
2. Trauma to the distal phalanx
3. Lesions of middle and near phalanges
4. Defeat rises up
Stages 1 and 2 do not require, in principle, hospitalization, the risk of amputation is close to zero even in the absence of appropriate treatment.
Stage 3 and 4 – severe frostbite. With no treatment, the risk of amputation is very high.
Immerse the limbs in water at a temperature of 38°C containing an antiseptic solution.
“Forced” rehydration: drink at least one litre of water.
Apply sterile dressings.
To prevent thrombosis, take aspirin.