The effects of preloading solutions on ischemia reperfusion markers in minor lower extremity operations with tourniquet application under spinal anesthesia

Orthopedic procedures of extremities requires a bloodless field obtained by tourniquet application. Tourniquet application, has consequences classified into systemic and local effects, is a good ischemia-reperfusion model in humans. Cristalloid and colloid solutions is being used as preloading solutions for preventing hypotension which is the most frequent complication of spinal anesthesia . In this study, our purpose was to investigate the effects of IV preloading solutions (%0.9 NaCl, %6 Hydroxyethyl starch (HES) (130/0.4) on ischemia-reperfusion markers in the minor lower extremity operations with tourniquet application under spinal anesthesia. ASA physical status I-II 40 patients aged between 18-65, undergoing minor orthopedic procedures under knee were included in the study. Patients randomised into two groups (Group Serum physiologic (SF) ve Group HES). We performed unilateral spinal anesthesia with 2 ml %0.5 hyperbaric bupivacaine after 10 mL/kg SF IV infusion to Group SF and 10 mL/kg %6 HES IV infusion to Group HES. Blood samples were obtained from antecubital vein for malondialdehyde (MDA), xanthine oxidase and hypoxanthine before tourniquet inflation and after ten minutes of tourniquet deflation. Tourniquet was applied at a pressure twice systolic arterial blood pressure. Hemodynamic datas were recorded during operation, hypotension was treated with ephedrine, bradycardia was treated with atropine. Results were analysed statistically. There was no significant difference between groups for hemodynamics datas. The number of patients who requires treatment for hypotension was similar between groups. There were no significant differences between MDA values before tourniquet inflation and after tourniquet deflation between two groups. Xanthine oxidase values after tourniquet deflation were lower significantly from xanthine oxidase values before tourniquet inflation in the Group HES (p<0.05). Hypoxanthine values after tourniquet deflation were similar with respect to the basal values in Group HES, however they were significiantly higher from values before tourniquet inflation in the Group SF (p<0.05). In conclusion, HES infusion may be beneficial for decreasing tourniquet related ischemia-reperfusion injury, but there is requirement for future studies to understanding exact mechanism.