Near-infrared spectroscopy (NIRS) monitoring in contemporary anesthesia and critical care.

Near-infrared spectroscopy (NIRS) is a noninvasive technology that continuously monitors regional tissue oxygenation. Originally used for assessment of oxygen saturation of the brain, its use has now been expanded to evaluation of oxygenation of tissues other than the brain. There is also growing evidence for the larger applicability of NIRS as an estimate of systemic venous saturation in correspondence with the adequacy of the circulatory status. New and promising advances may further this technology to become part of our standard armamentarium, in order to optimize patient care in daily anesthesia practice. The present paper briefly reviews the basic principles of operation, the inherent limitations of the technology and the clinical data that have been acquired with NIRS monitoring in the broad field of acute clinical medicine.