Microdialysis of the spinal cord during thoracic aortic cross-clamping in a porcine model

Objective: Utilising microdialysis to measure the changes of glucose, lacta te, pyruvate and glutamate levels in the spinal cord after cross-clamping o f the thoracic aorta in an established porcine model to monitor the degree of ischaemia. Design: Experimental study with a porcine model. Setting: University Hospital, Trondheim. Subjects: Six pigs. Main outcome measure: Lactate, pyruvate and glutamate concentrations in the microdialysis perfusate from the spinal cord. Results: A significant increase of the lactate-pyruvate ratio during the la st 30 min of the 1 h clamping period, with a maximum increase of 169% from the basal value the last 10 min before declamping. No evident change in thi s ratio between the clamping and the reperfusion period. No significant cha nge in glutamate levels during clamping or reperfusion period. Conclusion: Microdialysis reflects the ischaemic state of the spinal cord d uring crossclamping of the thoracic aorta in pigs, and is well suited to st udy each phenomena.