[Continuous monitoring to detect brain ischemia during carotid endarterectomy and aortic arch replacement by near infrared spectrophotometory--a case report].

We report two cases in which continuous monitoring was used to detect brain ischemia by 8-channel electroencephalograph (EEG), transcranial Doppler (TCD) of middle cerebral blood flow velocities and near infrared spectrophotometric monitoring (NIR) of bifrontal area simultaneously. The symptom of brain ischemia was indicated by NIR and TCD but not by EEG following temporary cross-clamping of the common carotid artery during carotid endarterectomy. According to this sign we successfully used temporary shunt during CEA. On the other hand, these methods of monitoring did not show abnormal findings of cerebral blood flow disorders during aortic arch replacement. Nevertheless, neurologic disorders were complicated postoperatively. In conclusion, these methods monitor carotid artery blood flow but not vertebral artery blood flow.