Burns
The epidermal injury known as a burn is usually caused by heat but can also be caused by radioactive, chemical, or electrical agents. Two factors affect burn severity: the depth of the burn and the extent of the burned area.
One way to classify burns is according to the depth of the burned area. In first-degree burns, only the epidermis is affected. There is redness and pain, but no blisters or
swelling. A classic example of a first-degree burn is a moderate sunburn. The pain subsides within 48-72 hours, and the injury heals without further complications or scarring. The damaged skin peels off in about a week.
A second-degree bum extends through the entire epidermis and part of the dermis. There is not only redness and pain, but also blisters in the region of the damaged tissue. The deeper the burn, the more prevalent the blisters, which enlarge during the hours after the injury. Unless they become infected, most second-degree burns heal without complications and with little scarring in 10-14 days. If the burn extends deep into the dermis, it heals more slowly over a period of 30-105 days. The healing epidermis is extremely fragile, and scarring is common. First- and second degree burns are sometimes referred to as partial-thickness burns.
Third-degree, or full-thickness, bums destroy the entire thickness of the skin. The surface of the wound is leathery and may be brown, tan, black, white, or red. There is no pain because the pain receptors have been destroyed, as have blood vessels, sweat glands, sebaceous glands, and hair follicles.
Obviously, the chances of a person surviving fourth-degree burns are not good unless a very affected.
The major concerns with severe burns are fluid loss, heat loss, and bacterial infection. Fluid loss is counteracted by intravenous administration of a balanced salt solution. Heat loss is minimized by placing the burn patient in a warm environment. Bacterial infection is treated by isolation and the application of an antibacterial dressing.
As soon as possible, the damaged tissue is removed, and skin grafting is begun. The skin needed for grafting is usually taken from other parts of the patient's body. This is called autografting, as opposed to heterografting, in which the graft is received from another person. Autografting is preferred because rejection rates are very low. However, if the burned area is quite extensive, it may be difficult to acquire enough skin for auto grafting.
As noted earlier, the severity and treatment of burns depends not only on their depth but also on the amount of area involved. A useful technique for estimating the extent of a burn, called the "rule of nines," is often employed. ln this method, the total body surface is divided into regions as follows: the head and neck, 9% of the total body surface; each upper limb, 9%; each lower limb, 18%; the front and back portions of the trunk, 18% each; and the perineum, which includes the anal and urogenital region, 1%.
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