Cellular Restitution after 3 h of Complete Tourniquet Ischemia

Abstract

Technique refinement in extremity surgery necessitates more cellular level information of the effects of tourniquet times exceeding the accepted 90-120 min. In present experiments, the cellular metabolic and functional restitution of canine skeletal muscle after 3 h of complete tourniquet ischemia was studied. During ischemia and after recirculation, repeated skeletal muscle samples were taken for ATP, CP [creatine phosphate] and lactate analyses. At the same time periods, blood from a regional vein and vena cava was drawn for pH, pyruvate and lactate analyses. Cellular function was evaluated from repeated measurements of transmembrane potentials. Tourniquet ischemia resulted in a rapid decrease of CP to 40% of the initial level within 1 h and a continuous decrease of ATP. The lactate levels increased continuously. The transmembrane potentials decreased from an initial level of -90 to -54 mV. Tourniquet release resulted in a hyperemic reaction and a rapid regain of tissue CP and ATP levels within 5 min of recirculation. There was a continuous washout of lactate up to about 1 h after the release and transmembrane potential normalization took about the same time. The latter parameters indicate that areas of no-reflow persisted up to 1 h after restored circulation. Apparently after a 3-h tourniquet ischemia, cellular energy metabolism and membrane function were completely normalized after about 1 h of recirculation.