Local cooling

Local cooling. An extremely low temperature is required, a large degree of heat loss per unit time is sufficient. An important role is played by wind and humidity (wet freezing). In supercooled tissues there is a decrease in metabolism and oxygen consumption. The minimum metabolism is initially sufficient to maintain cell viability. With passive heating of the affected tissues, metabolism and oxygen consumption begin to increase rapidly, but spasmodic arteries can not provide such a need. The consequence of this is hypoxia with tissue necrosis. Only after restoration of blood circulation in frostbitten tissues can the degree and depth of necrotic changes be determined. "Instant frostbite" occurs when you directly contact deep-frozen subjects (carbon dioxide in the form of snow, liquid air, nitrogen, metals at critical temperatures). Due to the rapidity of the effect, there is no vascular reaction, after thawing the tissues restore their function rather quickly.

There are 4 degrees of frostbite: I degree - cooling with a duration of 40-60 minutes, usually only the skin is affected (pale, numb and stiff limbs). As warming develops a phase of hyperemia, edema. After 1-2 weeks, the symptoms of frostbite disappear, there remains an increased sensitivity to cold. Often on the hands or feet, itching and painful blue-red swelling ("swelling from frostbite"); II degree-spasm of blood vessels is more pronounced, and is common. Tissue hypoxia leads to the exit of plasma from the vessels with the formation of blisters with serous-bloody contents; III-IV degree - necrosis of subcutaneous tissue, IV stage - necrosis of tendons, muscles, bones. Finally, the depth of necrosis can be established only after 4-6 days. With extensive frostbite III-IV degree for 1-2 weeks, an increase in body temperature to 38 ° C, leukocytosis. Rejection of necrotic tissues of fingers lasts 3-4 weeks, stop - 2-3 months.

Treatment. Intensive warming of the whole body by placing it in a hot bath (except frost-bitten areas!), Infusion of heat of isotonic sodium chloride solution, 5% glucose, warm enema. Locally-light grinding (by hand, not by rough woolen fabrics - the possibility of infection of the skin!). Smearing of the skin with alcohol or solutions of antiseptics. Aseptic dressing. Spasmolytics, vascular analeptics (compliance 2-4 ml intravenously), rheopolyglucin, heparin and other drugs that reduce the spasm of the peripheral vessels of the affected segment and improve microcirculation, plasmapheresis. At III-IV degree of frostbite, necrectomy is indicated.

The prognosis is serious.