The Brains of Very Preterm Newborns in Clinically Stable Condition May Be Hyperoxygenated

Abstract

OBJECTIVE: The objective was to compare cerebral oxygenation in preterm newborns with that in healthy term newborns. METHODS: Forty-six preterm newborns with gestational ages of <33 weeks and 25 healthy term newborns were included. The cerebral tissue oxygenation index (c-TOI) was measured by using near-infrared spectroscopy in clinical steady state on the first day of life (median age: 19.2 hours). The mean gestational ages and birth weights in the 2 groups were 29.1 ± 2.6 weeks versus 39.7 ± 1.3 weeks and 1307 ± 437 g versus 3484 ± 346 g, respectively. Three preterm infants needed mechanical ventilation and 11 received inotropic drugs. Later, 3 preterm infants developed intraventricular hemorrhage and 2 infants died. All term infants were healthy newborns recruited in the maternity ward. RESULTS: There was a significant difference in c-TOI (preterm: 78.6% [95% confidence interval: 76.9%–80.3%]; term: 74.7% [95% confidence interval: 72.3%–77.1%]). Preterm newborns had significantly lower fractional tissue oxygen extraction, which suggests lower oxygen extraction in this group. There was no significant correlation between head size and c-TOI. The mean peripheral oxygen saturation was 95% in both groups. The median blood Pco2 for the preterm infants was 6.1 kPa (range: 3.4–7.3 kPa). CONCLUSIONS: Cerebral oxygenation on the first day of life was higher in a group of relatively healthy, very preterm infants in stable condition, compared with healthy term newborns. Slightly elevated blood Pco2 could be the explanation. Prematurity itself does not seem to dispose preterm infants to global cerebral hypoxia.