Effects of acute bleeding on oxygen supply to the skeletal muscle in dogs

To study the effect of acute bleeding on the oxygen supply to the skeletal muscle, heparinized dogs were bled via an arterial cannula until mean arterial pressures of 25 and 50 mm Hg below initial value were reached. The shed blood was retransfused in reverse (50, 25 mm Hg) after correction of the acid-base imbalance in the dogs. Oxygen supply to the skeletal muscle was measured by means of a multiwire polarographic electrode placed on the sartorius muscle and was evaluated by means of ptO2 histograms. The ptO2 histograms showed that the oxygen supply to the skeletal muscle is severely impaired after a decrease in mean arterial pressure of 25 mm Hg. Further impairment was seen after a decrease in pressure of 50 mm Hg. During retransfusion tissue oxygenation was normalized only after all shed blood was retransfused and the initial mean arterial pressure was reached.