ArticlesBackground: Currently, reliable reference values of regional cerebral oxygen saturation (rScO 2 ) for different gestational age (GA) groups are lacking, which hampers the implementation of near-infrared spectroscopy (NIRS) alongside monitoring arterial oxygen saturation (SaO 2 ) and blood pressure in neonatal intensive care. The aim of this study was to provide reference values for rScO 2 and cerebral fractional tissue oxygen extraction (cFTOE; (SaO 2 − rScO 2 )/SaO 2 ) for small adult and neonatal NIRS sensors. Methods: In this study, 999 infants born preterm (GA <32 wk) were monitored with NIRS during the first 72 h of life. Mixed modeling was used to generate reference curves grouped per 2 wk of GA. In addition, the influence of a hemodynamically significant patent ductus arteriosus, gender, and birth weight were explored. results: Average rScO 2 was ~65% at admission, increased with GA (1% per week) and followed a parabolic curve in relation to postnatal age with a peak at ~36 h. The cFTOE showed similar but inverse effects. On average, the neonatal sensor measured 10% higher than the adult sensor. conclusion: rScO 2 and cFTOE reference curves are provided for the first 72 h of life in preterm infants, which might support the broader implementation of NIRS in neonatal intensive care. d espite advances in neonatal intensive care that have led to a decline in morbidity, preterm birth is still associated with neurological sequelae (1). Brain injury in preterm infants is often caused by disturbances in cerebral blood flow (CBF) and oxygenation (2-4). Evidence is accumulating that monitoring blood pressure alone is not enough to ensure adequate (cerebral) perfusion and oxygenation (5,6).Near-infrared spectroscopy (NIRS) is a technique that can be used to monitor regional cerebral oxygen saturation (rScO 2 ), being both a measure of cerebral oxygenation as well as a surrogate of CBF. NIRS monitoring can be applied for prolonged periods of time, even in the most vulnerable infants (7). It uses multiple wavelengths of NIR light and relies on the distinct absorption spectra of oxygenated (O 2 Hb) and deoxygenated (HHb) hemoglobin to calculate relative concentrations of O 2 Hb and HHb, which are then used to calculate the rScO 2 (O 2 Hb/(O 2 Hb + HHb)). Where pulse-oximetry only measures the oxygen saturation in arterial blood (SaO 2 ), NIRS makes no distinction between different (cerebral) blood volume compartments; therefore, the rScO 2 represents the oxygen saturation in a mixed arterial-capillary-venous compartment in an approximate 20:5:75 distribution (8).NIRS is increasingly being used as a trend monitor of cerebral oxygen supply in neonates admitted to the neonatal intensive care unit (NICU). Readily interpretable reference values could provide another way of using NIRS in neonates by identifying neonates at risk. In other words, to identify neonates whose rScO 2 resides at the outskirts (high or low) of what is considered "normal. " Furthermore, reliable reference values could benefit NIRS research by...

Background: Near-infrared spectroscopy (NIRS) is an upcoming clinical method for monitoring regional cerebral oxygen saturation (rScO 2 ) in neonates. There is a growing market offering different devices and sensors. Even though this technique is increasingly clinically applied, little is known about the similarities and/or differences in rScO 2 values between the different devices and sensors. The aim of this study was to compare the rScO 2 values obtained in (preterm) neonates with all available sensors of three frequently used NIRS devices. Methods: Fifty-five neonates admitted to our neonatal intensive care unit (NICU) were included in this study. rScO 2 was simultaneously monitored bilaterally with two different NIRS sensors (left and right frontoparietal) for at least 1 h. Then, the sensors were switched, and measurements were collected for at least another hour. results: We detected a rather close correlation between all investigated sensors from the three different NIRS devices, but absolute rScO 2 values showed substantial differences: BlandAltman analysis showed average differences from 10 to 15%. conclusion: Although the rScO 2 values correlated well between different NIRS sensors, sometimes there were substantial differences between the absolute rScO 2 values, which may complicate clinical application.

Cerebral oxygenation is not always reflected by systemic arterial oxygenation. Therefore, regional cerebral oxygen saturation (rScO2) monitoring with near-infrared spectroscopy (NIRS) is of added value in neonatal intensive care. rScO2 represents oxygen supply to the brain, while cerebral fractional tissue oxygen extraction, which is the ratio between rScO2 and systemic arterial oxygen saturation, reflects cerebral oxygen utilization. The balance between oxygen supply and utilization provides insight in neonatal cerebral (patho-)physiology. This review highlights the potential and limitations of cerebral oxygenation monitoring with NIRS in the neonatal intensive care unit.