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

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.

Prefabricated flaps: experimental and clinical review.

Prefabricated flaps are a useful tool for the reconstructive surgeon and present a number of advantages: 1. Specific preferred tissue composites, regardless of their native vascular origin, can be transferred as free or pedicled flaps. 2. Larger flaps of specialized tissue may be transferred safely. 3. Donor-site morbidity is reduced. 4. The functional outcome for the patients may be more satisfactory. The various methods of flap prefabrication include vascular induction through stage transfer; pretransfer delay, expansion, and grafting; the use of alloplastic materials; and tissue bioengineering. We have reviewed both the experimental and clinical research on flap prefabrication, describing the theory, technique, and advantages of each method.

Phagocytic activity of polymorphonuclear leucocytes in burns.

The phagocytic function of neutrophils has been studied in 50 Egyptians of both sexes and of various ages, suffering from burns of different depths and extents, and the results compared with data from 50 normal persons of similar sex and age. The nitro blue tetrazolium test (Gifford and Malawista, 1970), and the bacterial killing test (Quie et al., 1967), have been used during the first 24 hours, and then repeated at weekly intervals for 4 weeks. The phagocytic power showed no change during the study except in two patients with extensive burns during fatal septicaemia. The bactericidal capacity, and the formazan cell formation showed similar changes with a steady decrease from the first to the third weeks, followed by a rise during the fourth week. Similar changes were noticed in the serum albumin levels. The decline was more marked in burns of more than 50 per cent of the body surface area and during severe sepsis. Improvement coincided with healing.

The Use of Bipedicled Flaps in the Management of Pretibial Skin Defects.

Chronic ulceration or recurrent ulceration of scar tissue in the pretibial area can be a major problem. The operation to be described affords a safe and satisfactory method of covering the raw area left after excision of pathological tissue in this region by bipedicled full-thickness grafts brought forward from the medial and lateral aspects of the leg. The resultant defect over the calf is covered by bringing across a free skin graft from the opposite thigh.