[Near-infrared spectroscopy in the postanesthesia recovery care unit: noninvasive monitoring of peripheral perfusion].

Clinical signs of recovery, such as blood pressure or heart rate, do not accurately reflect the perfusion of organs and tissues in patients in critical condition. Of the various means for monitoring perfusion, regional monitors are the most sensitive. Near-infrared spectroscopy (NIRS), which analyzes infrared light detected after it has passed through red blood cells in tissues, provides a measure of oxygen saturation that is the most appropriate method for clinical situations. In patients with sepsis or multiple injuries, tissue oxygen saturation can be useful as an early indicator of shock, as a marker of recovery or need for transfusion, or as a prognostic factor. In spite of widespread interest in NIRS, however, there are gaps to fill in our understanding of clinical signs and physiology in relation to this technique before peripheral tissue monitoring can become routine in postanesthesia recovery care units.