Evolution of near-infrared spectroscopy (NIRS) monitoring of cerebral oxygenation during the first minutes of life: An up-to-date review.

Near-infrared spectroscopy (NIRS) is a technology capable of non-invasive, continuous measurement of regional tissue oxygen saturation (rStO2). No longer limited to the domain of laboratory research, this technology has become a routine bedside monitoring tool in neonatal intensive care units. The neonatal period is a unique stage in human life, during which the infant undergoes profound physiological adjustments essential for the transition from the intrauterine to the extrauterine environment. The temporal dynamics of regional cerebral tissue oxygenation during the first minutes after birth are among the most extensively investigated in contemporary neonatal research. This systematic qualitative review aims to summarize reference ranges defined as normal values or centile charts of cerebral oxygenation (cStO2) and cerebral fractional tissue oxygen extraction (cFTOE) during postnatal adaptation for term and preterm neonates. Systematic measurement and statistical evaluation of physiological values are essential for establishing benchmarks, especially for critically ill neonates.