This technique consists of a light emitting diode and two distant sensors attached to the fronto-parietal side of the skull. The concentration of oxygen is calculated by the differential signal between these two sensors. NIRS is used in neonates for the evaluation of the concentration of oxygen and hemoglobin. In consequence it can evaluate the brain hemodynamics. In neonates suffering from perinatal asphyxia, this technique can be quite useful. By evaluating tissue oxygenation extraction, this can reflect the amount of brain oxygenation. A reduced fractional tissue oxygenation extraction reflects either an increase in consumption or decreased oxygen delivery. The opposite applies as well. aEEG is routinely used to evaluate neonatal asphyxia but NIRS is becoming more commonly used. NIRS has also other uses such as for Alzheimer’s disease and Brain Tumors. I think EEG should be able to show the brain consequences of hypoxia but NIRS because it detects the level of oxygenation directly; it should be able to detect the problem earlier. Here is a good paper-
Toet MC, etal, Brain Monitoring in Neonates, Early Human Development, 85, 77-84
Adolfo Cotter, MD
May 24/2010
