Monitoring Neonatal Regional Cerebral Oxygen Saturation in Clinical Practice: Value and Pitfalls

Abstract

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 (rScO₂), cerebral fractional tissue oxygen extraction (cFTOE), which is derived from rScO₂, and systemic oxygen saturation. Its precision and pitfalls are discussed. At this stage, it is clear that NIRS-monitored oxygenation of the brain by rScO₂ 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 rScO₂ 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, rScO₂ 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.

Precision of cerebral oxygenation and hemoglobin concentration measurements in neonates measured by near-infrared spectroscopy

“…Van Bel et al 20 summarized nicely normal values of StO 2 in adults, term and preterm infants ranging from 58 to 75%, respectively, 49 to 75% and 54 to 85%. In accordance with our results, they reported no significant difference between the different groups.…”

“…1,2 To allow prevention or early intervention, continuous cerebral monitoring is important to detect cerebral aberrations in term and preterm neonates undergoing intensive care. [3][4][5] Near-infrared spectroscopy (NIRS) is a continuous and also noninvasive method to measure regional changes in cerebral tissue oxygenation and perfusion at the bedside. 6,7 Thus, NIRS is suitable for cerebral monitoring.…”

Near-Infrared Spectroscopy Measurements of Cerebral Oxygenation in Newborns during Immediate Postnatal Adaptation

“…Near-infrared spectroscopy (NIRS) is a well described non-invasive technique, taking advantage of the transparency of biological tissue to light in the near-infrared spectrum, and allows to explore changes in cerebral tissue oxygenation. [21][22][23][24] Newer near-infrared spectrometers allow additional measurement of a quantitative tissue oxygenation index (TOI) representing the ratio of O 2 Hb in total hemoglobin (O 2 Hb/[O 2 Hb+HHb]). It has been shown that NIRS is able to monitor cerebral hemodynamics in critically ill term and preterm infants.…”

Basal ganglia perfusion in the preterm infant during transition

“…Diffuse optical spectroscopy, such as near-infrared spectroscopy, offers reliable trend monitoring of global cerebral oxygenation but does not measure potentially important changes in the regional distribution of blood flow (14,15). Although superior vena cava blood flow, Doppler assessment of cerebral vessels, and cerebral oxygen saturations all have a sound theoretical basis for correlation with blood flow, these modalities are limited by being unable to directly measure blood flow in regions of interest.…”