Ischaemic preconditioning attenuates haemodynamic response and lipid peroxidation in lower-extremity surgery with unilateral pneumatic tourniquet application: a clinical pilot study.

INTRODUCTION The harmful effects of ischaemia-reperfusion on skeletal muscle during extremity surgery can be diminished by using medications or ischaemic preconditioning METHODS Twenty patients undergoing lower-limb surgery with use of a tourniquet for at least 1 hour were included in the study and randomised into two groups: a control group with only tourniquet application (T group; n=10); and an ischaemic preconditioning plus tourniquet group (IP-T group; n=10). Blood samples were obtained from the femoral vein of the relevant extremity before tourniquet application (baseline), immediately after tourniquet deflation (TD), at 10 minutes after the tourniquet deflation (TD(10min)) in the T group and additionally after ischaemic preconditioning in the IP-T group. Venous blood pH, partial oxygen pressure (P(vO2)), partial carbon dioxide pressure (P(vCO2)), lactate, potassium, sodium and glucose levels were analysed using a blood gas analyser. Plasma thiobarbituric acid reactive substances (TBARS) level, an index of lipid peroxidation and oxidative stress, was measured. Heart rate, noninvasive mean arterial pressure (MAP) and spontaneous breathing rate (SBR) were recorded at baseline, at TD, and TD(1min), TD(5min) and TD(10min). RESULTS MAP decreased and SBR increased significantly at TD, TD(1min) and TD(5min) compared with baseline, and venous blood TBARS level significantly increased at TD and TD(10min) compared with baseline in the T group (all P<0.05). No significant changes were observed in the IP-T group. Ischaemic preconditioning caused a rise in PvO2 and a decrease in venous blood pH, P(vCO2), and lactate levels, which was significant compared with baseline (P<0.05) CONCLUSION Ischaemic preconditioning attenuates haemodynamic response and lipid peroxidation during lower-extremity surgery with unilateral tourniquet application.