The role of allopurinol and deferoxamine in preventing pressure ulcers in pigs

Ischemia and reperfusion may be important in the pathogenesis of pressure u lcers. On the basis of this hypothesis, the effects of intermittent pressur e and the anti-free radical agents allopurinol and deferoxamine were studie d 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 quanti fied. A control group of pigs (n = 6) was untreated, the allopurinol group (n = 6) received oral allopurinol beginning 2 days before the experiment, a nd the deferoxamine group (n = 6) received an intramuscular injection of de feroxamine 2 hours before the experiment. Pressure (150 mmHg) was applied t o 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 press ure injuries in all animals. Allopurinol and deferoxamine improved cutaneou s brood flow and tissue oxygenation, but only deferoxamine could significan tly reduce cutaneous and skeletal muscle necrosis (p < 0.001). This study s uggests a future role for anti-free radical agents in the reduction of pres sure-induced injury.