ROLE OF GLUCOCORTICOIDS DURING SEVOFLURANE ANAESTHESIA IN TOURNIQUET-INDUCED ISCHEMIA- REPERFUSION INJURY

摘要

Oxygen-free radicals are considered to be important components involved in the physiopathological tissue alterations observed during ischemia/reperfusion (I/R). The application and release of tourniquets is often used in lower extremity surgery in order to obtain a clear operative field and to reduce blood loss. When the tourniquet is released, excessive formation of free radicals follows reperfusion and oxygenation. This study was designed to investigate two different doses of methylprednisolone (MP) administration effects in tourniquet-induced IR injury during exposure to sevoflurane anaesthesia. This placebo control study was designed to compare the effects of two doses of MP onto the I/R injury in patients in whom the tourniquet was used during elective lower extremity surgery under general anaesthesia with sevoflurane. 37 ASA physical status I or II patients scheduled for elective lower extremity surgery received MP 5 mg kg~(-1), 1 mg kg~(-1), respectively, following the induction of anaesthesia. Blood samples were drawn immediately before ischemia, end of ischemia and at 5, 30 min and 24 h of reperfusion. The main findings were that sevoflurane by itself or with 5 mg kg~(-1) doses of MP could be protective against I/R injury of tissue depending on the free radical scavenging features (MDA, FOX) and antioxidant effects (SOD), but not as effective as a protective agent against endothelial cell injury (nitrite-nitrate). Besides MP has an additive anti-lipid peroxidation activity and might be protective against reperfusion injury to endothelial cells.