Use of cerebral oximetry to monitor brain oxygenation reserves for skull base surgery.

We used cerebral oximetry based on near-infrared re-emittance spectroscopy for noninvasive evaluation of the cerebral regional oxygen saturation (rSO(2)) to preoperatively assess patients with skull base tumors and giant arterial aneurysms, for whom possible occlusion or partial resection of the internal carotid artery was considered. Monitoring cerebral oxygen saturation was performed during both endovascular (balloon) and open surgical test occlusions of the internal carotid artery. The presence (or absence) of changes in the cerebral oxygen saturation served as a criterion of the patient's tolerance to permanent occlusion of the internal carotid artery. In all cases the curves of saturation accurately corresponded to the clinical condition of the patients, primarily to the developing of neurological signs. Cerebral oximetry was an extremely informative and reliable technique for fast, easy, and noninvasive detection of changes in brain blood circulation. Generally, cerebral oximetry serves as a valuable adjunct in detection of brain tolerance to the occlusion of major arterial vessels and in monitoring the condition of the brain in regard to its oxygenation and perfusion.