The injury of human body caused by low temperature is freezing injury, which is divided into non freezing cold injury and freezing cold injury.
1、 Non freezing cold injury
1.Main cause: caused by low temperature below 10 ℃ to above freezing point and humid conditions. Such as chilblain, trench foot and impregnated foot. The local skin and blood vessels of the body exposed to low temperature below the freezing point contract, and the blood flow is slow, affecting cell metabolism. When the local temperature is normal, blood vessels dilate, congest and exudate.
2.Main symptoms: first, the feet, hands and ears are red and swollen, accompanied by itching or tingling, blisters, erosion or ulcer after infection.
3.First aid: apply Chilblain Cream on the local epidermis and warm compress twice or three times a day. For those with erosion or ulcer, use antibiotics and corticosteroid ointment or chilblain ointment.
2、 Freezing cold injury
1.Main causes: most of them occur in accidents or wartime, when the human body is exposed to low temperature below the freezing point and snowstorm in the field, falls into ice and snow, or is accidentally damaged by refrigerants such as liquid nitrogen and solid CO2.
2.Main symptoms: local frostbite is divided into four degrees.
3.Degree I frostbite: cortex is injured. Local redness and swelling, fever, itching and tingling. After a few days, the dry scab will fall off and heal without leaving scars.
4.Degree II frostbite: the damage reaches the dermis. Local redness and swelling are obvious, and blisters are formed. Conscious pain, if there is no infection, local scab will heal, and there are few scars.
5.Third degree frostbite: it damages the whole layer of skin and reaches the subcutaneous tissue. The wound changed from pale to dark brown, surrounded by redness, swelling, pain and bloody blisters. If there is no infection, the necrotic tissue will dry and form scabs, leaving scars after healing and slow recovery.
6.Grade IV frostbite: injury to muscle, bone and other tissues. Partial degree II frostbite. Dysfunction or disability remained after treatment.
7.First aid: rewarming is the basic means of treatment. First, get rid of low temperature environment and frozen objects. Do not bake clothes, shoes and socks with fire if their limbs are frozen. Take them off or cut them off after melting with warm water (about 40 ℃). Then soak the injured limb or the whole body with 38 ~ 40 ℃ warm water. The water temperature should be stable so that the local part can be warmed within 20 minutes and the whole body can be warmed within half an hour. When the limbs are ruddy, the skin temperature should reach about 36 ℃. Cardiac compression and artificial respiration were performed for patients with respiratory and cardiac arrest.