Effect of Pneumatic Tourniquet on Muscle Oxygen Tension

Recent investigations suggest that circulation in a limb can be reduced with a tourniquet to less than 1 per cent of the control limb, or even completely occluded. The development of tissue oxygen tonometry with implanted silastic tubes has provided new possibilities for assessing muscle tissue oxygen tension. In the present work, this method was employed to register the effect of tourniquet blockade on the lower limb muscle PO₂, in rabbits. The duration of the tourniquet blockade was 60, 120 and 180 minutes. The baseline muscle PO₂, in the tibialis anterior muscle was 22.6 ± 0.6 mmHg. During the tourniquet blockade the oxygen tension dropped to minimal values between 9.2 ± 0.5 and 10.7 ± 0.6 mmHg in these experimental groups, but the tissue microclimate never reached fully anoxic conditions. The rapid response of muscle PO₂ to oxygen breathing after release of the blockade suggests that limb microcirculation tolerates tourniquet occlusion well.