Which of the following statements correctly describes the clinical use of near-infrared spectroscopy (NIRS)?
A. It reads pulsed arterial saturation like a pulse oximeter.
B. It reads the mixed venous oxygen saturation.
C. It does not require a pulse for accurate measurements.
D. It reads accurately in icteric patients.
The answer is C. NIRS readings do not require a pulsatile flow. Contrary to popular belief, NIRS technology is neither pulse oximetry nor an indirect mixed venous saturation. It does not require pulsatile flow to measure oxygenation and therefore can be used during cardiopulmonary bypass and arrest situations. A NIRS monitor placed on the forehead may measure regional cerebral saturation. It has been placed on the flank in some patients and used for regional RENAL blood flow. In healthy children, cerebral oxygen saturations are around 68% +/-10%. Icteric patients have depressed cerebral saturation values due to light absorption by bilirubin.