Precision of time-resolved near-infrared spectroscopy-based measurements of cerebral oxygenation in preterm infants

Significance: Time-resolved near-infrared spectroscopy (t-NIRS) is a new technology; at the moment, data on its precision in preterm infants are rare. Aim: Therefore, the aim of this study was to analyze the precision of t-NIRS-based measurements of the cerebral oxygenation in preterm infants. Approach: In 70 neonates [age: 4.7 ± 2.0 days, sex (f/m): 33/37], cerebral oxygenation (t-rSO2) was measured with an optode placed over the left frontotemporal lobe on the head, measurement duration was 1 min, and a reapplication was done for four further times (five applications). Results: Overall mean for t-rSO2 values was 62.2 % ± 4.1 % . We found a within-patient variation for t-rSO2 of 2.6%. Furthermore, 95% of all observed values were within a range of ±5 % from the mean when looking on several reapplications and ±2 % when looking within one application. Most of the variation in t-rSO2 (60.4%) contributed to differences between patients. The remaining 39.6% of the variation was due to measurement errors and real changes of the measured signal within the neonates. Conclusions: Since within-patient variation of t-rSO2 measures were below a clinical meaningful threshold of 5%, the measurement can be denoted as precise.