Pathophysiology of Burns
Burns are caused by a transfer of energy from a heat source to the body. Heat may be transferred through conduction or electro-magnetic radiation. Burns are categorized as thermal (which in-cludes electrical burns), radiation, or chemical. Tissue destruction results from coagulation, protein denaturation, or ionization of cellular contents. The skin and the mucosa of the upper airways are the sites of tissue destruction. Deep tissues, including the vis-cera, can be damaged by electrical burns or through prolonged contact with a heat source. Disruption of the skin can lead to in-creased fluid loss, infection, hypothermia, scarring, compromised immunity, and changes in function, appearance, and body image.
The depth of the injury depends on the temperature of the burning agent and the duration of contact with the agent. For ex-ample, in the case of scald burns in adults, 1 second of contact with hot tap water at 68.9°C (156°F) may result in a burn that destroys both the epidermis and the dermis, causing a full-thickness (third-degree) injury. Fifteen seconds of exposure to hot water at 56.1°C (133°F) results in a similar full-thickness injury. Temperatures less than 111°F are tolerated for long periods with-out injury.
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