The effects of different anesthesia techniques on free radical production after tourniquet-induced ischemia-reperfusion injury at children's age.

Background/aim: Reperfusion of previously ischemic tissue leads to injuries mediated by reactive oxygen species. The aim of the study was to investigate the effects of different anesthesia techniques on oxidative stress caused by tourniquet-induced ischemia-reperfusion (IR) injury during extremity operations at children's age.

Methods: The study included 45 patients American Society of Anesthesiologists (ASA) classification I or II, 8 to 17 years of age, undergoing orthopedic procedures that required bloodless limb surgery. The children were randomized into three groups of 15 patients each: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia with propofol (group T) and regional anesthesia (group R). Venous blood samples were obtained at four time points: before peripheral nerve block and induction of general anesthesia (baseline), 1 min before tourniquet release (BTR), 5 and 20 min after tourniquet release (ATR). Postischemic reperfusion injury was estimated by measurement of concentration of malondialdehyde (MDA) in plasma and erythrocytes as well as catalase (CAT) activity.

Results: Plasma MDA concentration in the group S was significantly higher at 20 min ATR in comparison with the groups T and R (6.78 +/- 0.33 micromolL-1(-1) vs. 4.07 +/- 1.53 and 3.22 +/- 0.9. micromolL-1(-1), respectively). There was a significant difference in MDA concentration in erytrocythes between the groups S and T after 5 min of reperfusion (5.88 +/- 0.88 vs. 4.27 +/- 1.04 nmol/mlEr, p < 0.05). Although not statistically significant, CAT activity was slightly increased as compared to baseline in both groups S and R. In the group T, CAT activity decreased at all time points when compared with baseline, but the observed decrease was only statistically significant at BTR (34.70 +/- 9.27 vs. 39.69 +/- 12.91 UL-1, p < 0.05).

Conclusion: Continuous propofol infusion and regional anesthesia techniques attenuate lipid peroxidation and IR injury connected with tourniquet application in pediatric extremity surgery.