Study of the preconditioning effect of sevoflurane against acute ischemia reperfusion injury of the lower limb skeletal muscles after tourniquet deflation

ABSTRACT

Preconditioning [PC] is a process where cells or tissues exposed to a sublethal stimulus are transiently protected from a subsequent normal lethal stress. Many forms of preconditioning have been investigated, such as ischemic, thermal, pharmacologic, or gas inhalation. The present study aimed to study the preconditioning effect of sevoflurane as a prophylaxis against ischemia reperfusion injury of the lower limb skeletal muscles after tourniquet deflation. The study was carried out on 40 adult patients. The patients were randomly assigned into two equal groups, each one including 20 patients. Group I received sevoflurane anesthesia. Group II received spinal anesthesia using heavy bupivacaine 15 mg. Biochemical parameters of muscle injury including serum CPK, AST, K, Ca, ABGs, lactic acid, IL-6 and TNF[alpha] were compared between both groups before induction of anaesthesia, and 5 min after deflation of the tourniquet. Both groups showed an increase in CPK and AST levels 5 minutes after tourniquet deflation but the increase was significantly higher in group II; CPK was 61.1+13.6 IU/L in the sevoflurane group versus 76.2+11.4 IU/L in the control[spinal] group. Also AST was 28.4+6.9 IU/L in the sevoflurane group versus 55.5+6.3IU/L in the control group. Both groups developed increase in serum K 5 min. after tourniquet deflation and the increase was significantly higher in the control group; serum K was 4.4+0.71 meq/L in the sevoflurane group vs. 5.1+0.4 meq/L in the control group. Both groups showed an increase in serum Ca level 5 minutes after tourniquet deflation but there was no significant difference between them. There were no significant differences in PaO2 or arterial pH between both groups, however the control group showed a significantly higher PaCO2 and a significantly lower arterial HCO3 - values than in the sevoflurane group 5 min. after tourniquet deflation. Serum lactic acid, IL-6 and TNF[-alpha] significantly increased in both groups 5 min. after tourniquet deflation but the rate of increase was higher in the control group; serum lactic acid was 1.30 + 0.25 mg/dl in the sevoflurane group vs. 1.98 + 0.27 mg/dl in the control group, IL-6 was 50.4 + 12.6 pg/ml in the sevoflurane group vs. 66.7 + 9.9pg/ml in the control group, and TNF[-alpha] was 15.6 + 6.4 pg/ml in the sevoflurane group vs. 28.4 + 5.8 pg/ml in the control group 5 min. after tourniquet deflation. In conclusion, the findings of the study has shown that sevoflurane has a preconditioning effect on human skeletal muscles as evidenced by a lower biochemical parameters of muscle injury