Tissue glucose and lactate following vascular occlusion in island skin flaps

Neurovascular island skin flaps were elevated in the right groin area of Sprague-Dawley female rats weighing from 200 to 250 gm. Survival rates of the flaps were determined following venous and/or arterial occlusions of the femoral vessels. All the flaps exhibited an 80 percent decrease in tissue glucose content and an increase in tissue lactate content 4 to 7 times normal during venous and/or arterial occlusion. In the groups occluded for 8 hours, venous occlusion resulted in loss of all the flaps; arterial occlusion yielded survival of 70 percent of the flaps; and occlusion of both vessels yielded survival of 30 percent of the flaps. The results indicate that venous occlusion is more detrimental to flap survival than arterial occlusion. Surviving flaps exhibited a glucose content of 3.5 times normal, and dying flaps exhibited a glucose content of 20 percent of normal and a lactate content of 5.1 times normal. The ratio of tissue lactate to glucose may serve as an index for tissue viability: normal flaps, 0.3, surviving flaps, 1.2, and dying flaps, 7.5.