Spinal Cord Metabolism During Thoracic Aortic Cross-clamping in Pigs with Special Reference to the Effect of Allopurinol

Objective investigate the metabolic response of the spinal cord and the effect of allopurinol following cross clamping of the descending thoracic aorta in a porcine model. Design experimental animal study.Materials twelve domestic swine. Six pigs were pre-treated with allopurinol, while six pigs served as controls.Methods measurement of extracellular concentrations of glucose, pyruvate, lactate, glycerol and glutamate using microdialysis in the lumbar spinal cord. Measurement of lumbar spinal blood flow using laser Doppler technique. Results for all animals there was a significant decrease in concentrations of glucose and pyruvate together with a significant increase in the lactate–pyruvate ratio during aortic cross clamping. There was also a significant increase in glycerol concentrations 60 min after cross clamping, and a significant decrease in glutamate concentrations after 50 min. No differences in concentrations of glucose, pyruvate, lactate and glutamate or the glutamate–pyruvate ratio were observed between animals used as controls and those treated with allopurinol. The laser Doppler flux decreased to 40% of pre cross-clamp level, returning to normal values at declamping. Conclusion the changes in energy-related metabolites reflect a considerable ischaemia in the spinal cord tissue but there was no convincing effect of allopurinol on the lumbar spinal cord metabolism during thoracic aortic cross clamping in this model.