Elevation of thromboxane in pressure wounds

Arachidonic acid metabolites have been implicated as mediators of progressive dermal ischemia. Decubitus ulcer formation results from chronic mechanical pressure on the skin which results in a diminished blood supply to the skin and underlying tissues. To evaluate the role of thromboxanes in pressure wounds, we measured TxB 2, a stable metabolite of TxA 2, in spontaneously occurring pressure wounds on Greyhound dogs. In pressure wounds in which the skin was showing early signs of pressure necrosis but was still intact, elevated TxB 2 concentrations were found in healthy appearing tissues immediately adjacent to the pressure wounds, in the inner edge of the wounds, and in the center of the wounds. Significantly greater TxB 2 concentrations (P < 0.05) were found in the center of the intact wounds versus the TxB 2 concentrations in the inner edge of the wounds or in healthy appearing tissues adjacent to the wounds. In pressure wounds in which the center of the wound had ulcerated or had an eschar, elevated TxB 2 concentrations were found in tissues in the inner edge of the wounds and in healthy appearing tissues immediately adjacent to the pressure wounds. These results demonstrate the occurrence of elevated thromboxane concentrations in and around spontaneously occurring pressure wounds.