Effect of high-dose of methylprednisolone on tourniquet ischaemia

Abstract

Pneumatic tourniquets are widely used tbr limb surgery and facilitate intravenous regional anaesthesia. The extremity below the tourniquet becomes ischaemic, resulting in respiratory and metabolic acidosis, and skeletal cell damage) ,2 Biochemically, ischaemia and hypoxia are very' similar to shock; a primary metabolic abnormality is a rapid and considerable reduction in the aerobic production of energy)Massive doses of eorticosteroids, including methylprednisolone, have been found to have beneficial effects in different shock states ~6 The mechanism for the beneficial effects has not been clearly determined, but several hypotheses have been proposed. These include a cell membrane stabilizing effect, 7 reducing the liberation of vasoactive substances, ~ a direct metabolic effect, 9 and a vasodilative effect. ~0 The purpose of this study was to investigate, using a dog model, whether a corticosteroid such as methylprednisolone could attenuate the pathophysiological changes due to tourniquet-induced ischaemia. MethodsSeven large mongrel dogs weighing 23-35 kg were used for this study. The dogs were anaesthetized with pentobarbitone 30 rag. kg -1 IV. The trachea was intubated in order to assure an adequate airway, and then allowed to breathe spontaneously.IV catheters, 16 gauge, were placed in bath hind legs tbr venous access, and control venous blood samples were drawn. Identical paediatric size tourniquets were applied to the thigh of both hind legs and connected via a Y connector to a Shook tourniquet unit. Two 20 ml aliquots of venous blood were drawn from each dog's foreleg. Methylprednisolone, 3 mg'kg -I body weight, was dissolved in one of these samples of blood as a vehicle. The tourniquets were then simultaneously inflated to 600 mmItg. Blood with methylprednisolone was then injected into one of the tourniquet-occluded legs. The other 20 ml of autologous blood without methylprednisolone was injected into the opposite leg.Venous blood samples were taken from both legs at 30, 60, and 120 rain after tourniquet inflation. At 120 rain, after blood sample collection, the tourniquets were deflated, and samples were taken at 5 and 30 rain after tourniquet release.CAN J ANAESTH |98S / 35:5 t pp4~-8

Hydroxyl Radical Formation in Skeletal Muscle of Rats with Glucocorticoid-Induced Myopathy

“…Several researchers have investigated the use of GC in palliative therapy for muscular dystrophy, especially Duchenne muscular dystrophy, and have noted a decrease in CK activity (29). High dose steroid administration has been found to suppress CK, which tends to increase in ischemic-reperfusion injury models of skeletal muscle (30). The beneficial effect of steroid might be due to its anti-inflammatory effect (31), cellular membrane stabilization (32) or a direct metabolic effect (33) on skeletal muscle cells.…”

Effects of Folinic Acid Administration on Lower Limb Ischemia/Reperfusion Injury in Rats

“…To assess the potential therapeutic effect of FA, we have chosen biochemical parameters that are widely used in clinical practice (AST, ALT, CK, LDH, ALP, creatinine and ions such as K + , Na + and Cl − ), and also commonly used in several models of IRI, both in experimental and clinical studies [ 38 , 43 , 44 , 45 , 46 , 47 , 48 ]. Specific oxidative stress markers provide important information at the experimental level.…”

Extremity Tourniquet Deflation Increases End-Tidal Pco2

“…They reported that hindleg venous oxygen tension and pH decreased, and Pco,, lactic acid, creatine kinase, and lactic dehydrogenase rose steadily 30, 60, and 120 min after tourniquet inflation in both legs (5). However, these changes were significantly less in the methylprednisolone-treated legs.…”