[An index of cerebral perfusion: noninvasive monitoring of regional cerebral oxygen saturation by use of near-infrared spectroscopy (NIRS, NIRO) or NIRS cerebral oximetry (INVOS)].

Noninvasive monitoring of regional cerebral oxygen saturation has been introduced in clinical settings for estimation of cerebral perfusion and cerebral blood flow. In this article, I have described several issues regarding the usefulness and clinical limitations associated with the use of these monitors, as well as relevant information on basic principles of monitoring. At present, there is not enough clinical data concerning critical levels of measured variables that are essential for safe perioperative management of patients susceptible for cerebral ischemia.