Monitoring neonatal regional cerebral oxygen saturation in clinical practice: value and pitfalls

This review focuses on the clinical use of near infrared spectroscopy (NIRS) to assess brain oxygenation by the tissue oxygenation index (TOI), and monitoring regional cerebral oxygen saturation (rScO(2)), cerebral fractional tissue oxygen extraction (cFTOE), which is derived from rScO(2), and systemic oxygen saturation. Its precision and pitfalls are discussed. At this stage, it is clear that NIRS-monitored oxygenation of the brain by rScO(2) or TOI lacks the precision required to be used as a robust quantitative variable to monitor cerebral oxygenation. Intra- and especially interpatient variability are too large for this aim. On the other hand, when used merely as a trend monitor in the individual patient, substantial changes in rScO(2) or TOI and consequently of cFTOE, larger than the limits of agreement, can yield important clinical information that suggest an intervention. Since neonatal intensive care is for a substantial part 'brain orientated' this approach seems conceivable. This gives rise to the conclusion that NIRS-monitored TOI, rScO(2) and cFTOE increasingly will have a role in clinical practice as semiquantitative indicators of changes in cerebral oxygenation and oxygen extraction. Combination with other (cerebral) parameters such as amplitude-integrated EEG and blood pressure seems promising for further optimization of monitoring the immature brain.