Reply to Toumpoulis

Spinal cord, Aortic cross-clamping, Ischemic preconditioning, Evoked potentials

We appreciate the comments of Ioannis K. Toumpoulis about our paper concerning the use of immediate ischemic preconditioning based on somatosensory evoked potentials to prevent spinal cord injury [1]. In that study, it was shown that ischemic tolerance could be immediately achieved in the spinal cord against a clinically relevant ischemic insult, since ischemic preconditioning was based on the proper selection of induction times and intervals in dogs. This observation was obtained without significant differences between the groups with regard to proximal and distal aortic pressures at baseline, during the aortic cross-clamping and at the reperfusion period, as mentioned. During the aortic cross-clamping period, low doses of sodium nitroprusside were used to reduce the arterial blood pressure, explaining the described results. Nevertheless, no important hypotension was observed during the reperfusion interval in all the experiments of the three groups and it was not possible to detect any correlation between neurologic or histopathologic outcome with differences in arterial pressure during reperfusion or aortic cross-clamping time intervals.

We agree with Toumpoulis and coworkers [2,3] that hypotension episodes during the reperfusion period may influence the neurologic outcome in these experimental models of spinal cord ischemia after aortic cross-clamping. However, this finding does not appear to have influenced our data.