Transient hyperoxia does not affect regional cerebral tissue oxygen saturation in moderately preterm or term newborns

AIM: Even short periods of hyperoxia may induce prolonged cerebral vasoconstriction in newborn infants, and this could theoretically lead to cerebral ischaemia even once normoxia is re-established. This study aimed to investigate the effect of brief hyperoxic exposures on regional cerebral tissue oxygen saturation (rStO2 ) and to evaluate whether any observed prolonged cerebral vasoconstriction was related to maturity.

METHODS: The study included 30 infants with a postmenstrual age of more than 32 weeks, who were treated with nasal continuous positive airway pressure and a fraction of inspired oxygen of ≤0.3. The INVOS 5100C oximeter was used to measure rStO2 before, during and after two hyperoxic exposures. If hyperoxia induced a prolonged cerebral vasoconstriction, posthyperoxic rStO2 would be expected to decrease.

RESULTS: rStO2 increased slightly after the first hyperoxic exposure, with a mean difference of 1.37% (95% CI 0.15, 2.6). After the second oxygen exposure, rStO2 remained unchanged with a mean difference of -0.4% (95% CI -1.6, 0.78). Differences in rStO2 were not related to gestational age in either of the two hyperoxic episodes.

CONCLUSION: We found no evidence to support the theory that transient hyperoxia induces prolonged cerebral vasoconstriction in infants with a postmenstrual age above 32 weeks.