A histometric analysis of skeletal myofibers following 90 min of tourniquet ischemia and reperfusion.

Routine tourniquet use causes sublethal hypoxic cellular injury and results in edema formation. Using a histochemical morphometric technique, edema caused by 90 min of tourniquet-induced ischemia and 3 hr of reperfusion is measured in the different muscle fibers of a primate model. The degree of cellular swelling is shown to be related to the fiber's metabolic dependence upon oxygen. After reperfusion, predominantly oxidative type 1 fibers show a 29% increase in diameter, P less than 0.0005, type 2a fibers which are both oxidative and glycolytic increase by 7%, P less than 0.005, and the glycolytic type 2b fibers increase by 5%, P less than 0.01. A 48% increase in interfiber distance occurs with reperfusion, P less than 0.01. By quantifying the different fibers' responses to ischemic injury, this method may be of use in investigating the pathophysiology and prevention of reperfusion injury and the post-tourniquet syndrome.