INTRATHECAL OXYGEN CONCENTRATION AS A NEW INDICATOR OF SPINAL-CORD ISCHEMIA

A number of approaches have been put forward to monitor spinal cord is chemia during thoracic and thoracoabdominal aortic occlusion. However, none of these can ultimately prevent devastating complications which result from ischemic spinal cord injury. A direct measurement of the o xygen content of the spinal cord may accurately indicate the perfusion state, but in practice it is impractical. We surmised that intratheca l and/or epidural oxygen concentration(I-pO(2) and E-pO(2), respective ly) accurately reflect oxygen content in the spinal cord. So, we exami ned whether or not I-pO(2) and/or E-pO(2) correlated with the spinal c ord pO(2) (S-pO(2)) in dogs. In nine mongrel dogs, a model of graded s pinal cord ischemia was developed by stepwise alternation of the level of aortic occlusion with an intraaortic balloon catheter. I-pO(2), E- pO(2) and S-pO(2) were measured with a mass spectrometer. Our results show that, both I-pO(2) and E-pO(2) significantly correlated with S-pO (2). I-pO(2) correlated with S-pO(2) better than E-pO(2) did. Therefor e, I-pO(2) can be used as a new indicator for spinal cord ischemia, an d I-pO(2) monitoring would be useful to prevent paraplegia associated with thoracic aortic surgery.