Ischemia and reperfusion may be important in the pathogenesis of pressure ulcers. On the basis of this hypothesis, the effects of intermittent pressure and the anti-free radical agents allopurinol and deferoxamine were studied in a pig model in which a pressure of 150 mmHg was applied intermittently to the scapulae. Cutaneous blood flow, transcutaneous oxygen tension, skin and muscle damage, and muscle levels of adenosine triphosphate were quantified. A control group of pigs (n = 6) was untreated, the allopurinol group (n = 6) received oral allopurinol beginning 2 days before the experiment, and the deferoxamine group (n = 6) received an intramuscular injection of deferoxamine 2 hours before the experiment. Pressure (150 mmHg) was applied to the scapulae for 210 minutes, and it was relieved for 30 minutes. This 4-hour cycle was repeated continuously for 48 hours, and it resulted in pressure injuries in all animals. Allopurinol and deferoxamine improved cutaneous blood flow and tissue oxygenation, but only deferoxamine could significantly reduce cutaneous and skeletal muscle necrosis (p < 0.001). This study suggests a future role for anti-free radical agents in the reduction of pressure-induced injury.

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