Validation of Cerebral Venous Oxygenation Measured Using Near-Infrared Spectroscopy and Partial Jugular Venous Occlusion in the Newborn Lamb

Abstract

Near-infrared spectroscopy combined with partial jugular venous occlusion (JVO) offers promise for determining cerebral venous saturation (CSvO2) in sick preterm infants, but has not been validated in the newborn brain or under conditions of hypoxaemia. We assessed the accuracy of the CSvO2 estimate using cerebral venous oxygen saturation in superior sagittal sinus blood (SSSO2) as the ‘gold standard’. Comparisons were made in seven newborn lambs over a wide range of arterial oxygen saturations (SaO2) of 20% to 100%. Overall, median (range) CSvO2 was 49.8% (10.6% to 88.5%), whereas SSSO2 was 45.5% (4.3% to 76.6%); Bland—Altman analysis revealed a mean difference (CSvO2—SSSO2) of 5.1% and limits of agreement of ±27.4%. The change in cerebral blood volume (Δ CBV) induced by JVO increased with SaO2 ( P <0.05). In addition, the strength of the correlation of CSvO2 with SSSO2 progressively improved with increasing change in total haemoglobin concentration (Δ HbT) induced by JVO. With Bland—Altman analysis repeated for data with Δ HbT >30 μmol cm, the mean difference (CSvO2—SSSO2) decreased to 2.4% with limits of agreement of ±18.8%. We conclude that the accuracy of estimating CSvO2 varies with the Δ CBV induced by JVO. Potential differences of optical properties between the head of the lamb and the human infant suggest that caution be exercised in directly applying these data to the human newborn. Nevertheless, this critical aspect of the JVO technique needs to be taken into consideration in developing an accurate measurement for sick preterm human infants.