Abstract

AIMS: To describe the range of central venous oxygen saturation (ScvO2) values in stable newborn infants breathing room air; to examine the correlation between ScvO2 and arterial oxygen saturation (SaO2); to describe fractional oxygen extraction; and the shunt index, an estimate of the venous admixture. METHODS: A prospective clinical observational study was made of 10 preterm infants breathing room air after the acute phase of respiratory distress syndrome, and with an umbilical venous catheter in situ. A fibre optic catheter remained in the right atrium for continuous measurement of oxygen saturation. RESULTS: ScvO2, SaO2, blood pressure and heart rate were registered every 15 minutes. Fractional oxygen extraction and shunt index were calculated. SaO2 and ScvO2 were 93.4 (SD 3.7)% and 73.56 (5.25)%, respectively. In seven patients ScvO2 values correlated significantly with SaO2. Fractional oxygen extraction was 0.21 (0.04) and was significantly correlated with ScvO2. The shunt index was 24% (12) and was significantly correlated with SaO2. CONCLUSIONS: Stable preterm infants breathing room air had an ScvO2 ranging from 65% to 82% (5th and 95th percentile), which corresponded to SaO2 > or = 86%. ScvO2 values were significantly correlated with SaO2 in most patients.