Near-infrared spectroscopy for monitoring tissue oxygenation in the critical care setting

Near-infrared spectroscopy is a noninvasive technique to monitor oxygen availability and utilization at the tissue level, allowing semiquantitative measurement of hemoglobin oxygenation and volume. Specialized algorithms allow assessment of the redox state of mitochondrial cytochrome aa3 and, with the use of simple tracers, regional blood flow. Near-infrared spectroscopy has enormous potential for use in monitoring clinical trends in tissue oxygenation and answering mechanistic questions regarding oxygen sufficiency in various settings.