[Biological changes induced by the removal of the tourniquet in orthopedic surgery]

In 49 patients undergoing surgery on the lower limb with the use of a tourniquet, arterial PO2 and PCO2 were determined. In 16 cases they were also determined in the ischemic limb. In 40 of these patients coagulation studies were done and in 8 cases on blood from both the general circulation and from the ischemic limb. Some minutes after recirculation, PCO2 of the general circulation increased by 6.7 +/- 9 mm Hg. This increase is closely correlated with ischemia time and patient's weight. In the ischemic limb, PCO2 is about 72 +/- 10 mm Hg. In the general circulation, PO2 decreased by 21,6 +/- 42 mm Hg after recirculation. The most important changes were found in aged patients. PO2 in the ischemic limb decreased by 19 mm Hg. The changes in systemic PO2 and PCO2 are probably due to the return of blood from the ischemic limb in the general circulation. No changes of the coagulation factors were found with the exception of a small increase of anti-plasmine. Fibrinolysis occurred in 5 of the 8 patients studied.