1
عمومی::
انعقادی
Locally, thermal injury causes coagulative necrosis of the epider- mis and underlying tissues; the depth of injury depends on the temperature to which the skin is exposed, the specific heat of the causative agent, and the duration of exposure.
Burns are classified into five different causal categories and depths of injury. fte causes include injury from flame (fire), hot liquids (scald), contact with hot or cold objects, chemical exposure, and conduction of electricity (Box 19-2). fte first three induce cellular damage by the transfer of energy, which induces coagulation necrosis.
membranes in addition to the transfer of heat and can cause a coagulation or colliquation necrosis.
Once the inciting focus is removed, however, the response of local tissues can lead to injury in the deeper layers. fte area of cutaneous or superficial injury has been divided into three zones: zone of coagulation, zone of stasis, and zone of hyperemia (Fig. 19-1). fte necrotic area of burn where cells have been disrupted is termed the zone of coagula- tion. ftis tissue is irreversibly damaged at the time of injury. fte
area immediately surrounding the necrotic zone has a moderate degree of insult with decreased tissue perfusion. ftis is termed the zone of stasis and, depending on the wound environment, can either survive or go on to coagulative necrosis. fte zone of stasis is associated with vascular damage and vessel leakage. ftrombox- ane A2, a potent vasoconstrictor, is present in high concentrations in burn wounds, and local application of inhibitors improves blood flow and decreases the zone of stasis.
واژگان شبکه مترجمین ایران