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Definition of Thermal Burns
A thermal burn is an injury caused by exposure to heat sufficient to cause damage to the skin, and possibly deeper tissue. Most thermal burns are caused in one of the following ways, FLAME, HOT LIQUIDS, HOT OBJECTS, FLASH INJURIES and SUNBURN. The burn wound is a complex and dynamic injury characterized by a zone of coagulation, surrounded by an area of stasis, and bordered by an area of erythema. Depending on the severity of the thermal burn the zone of coagulation or complete capillary occlusion may progress by a factor of 10 during the first 48 hours after injury. Edema formation is rapid in the area of injury but also develops in distant, uninjured tissue. There are changes also occurring in the distant microvasculature where red cells aggregate, white cells adhere to venular walls, and platelet thromboemboli occurs. This is a progressive ischemic process which, when set in motion, may extend the damage dramatically during the early days after injury. The continuing tissue damage seen in thermal injury is due to the failure of the surrounding tissue to supply borderline cells with oxygen and nutrients necessary to sustain viability. The impediment of circulation below the injury leads to desiccation, as fluid cannot be supplied via the thrombosed or obstructed capillaries. Topical agents and dressings may reduce, but do not prevent, desiccation of the burn wound and the inexorable progression of the injury to deeper layers. Regeneration cannot take place until equilibrium is reached; hence, healing is retarded. Prolongation of the healing process may lead to excessive scarring. Hypertrophic scars are seen in 4 per cent of patients taking 10 days to heal, in 14 per cent of patients healing in 14 days or less, in 28 per cent of patients taking 21 days, and up to 40 per cent of patients taking longer than 21 days to heal.