321 Reproducibility of Cerebral Tissue Oxygen Saturation Measurements by Near Infrared Spectroscopy in Newborn Infants

Abstract

Objectives: Cerebral tissue oxygen saturation (StO2) may be a relevant parameter to assess brain oxygenation in intensive care. Near infrared spectroscopy (NIRS) is able to measure this parameter, but so far the reproducibility of such measurements has been too low due to inhomogeneities. The aim of this study was to test a novel sensor geometry, which is based on two source and two detector locations, which are arranged symmetrically to reduce the influence of superficial inhomogeneities.Methods: Thirty clinically stable, spontaneously breathing newborn infants with a gestational age of 34.2±3.1 weeks, birth weight of 2295±970g and postnatal age of 10.2±14.9 days were measured four times for one minute by NIRS on the lateral head. Between measurements the sensor was replaced. The reproducibility was calculated by a linear mixed effects model.Results: The mean StO2 was 79.99±4.47% with a reproducibility of 2.76% and a variability of 4.20% between infants. The error of measurement only accounts for 30% of the variability.Conclusions: The novel sensor geometry leads to much more precise measurements compared to previous studies (e.g. ∽5% reproducibility for the NIRO 300). For this reason the measured StO2 values do not require averaging and are therefore more clinically relevant.