Cerebral oxygenation immediately after birth and long-term outcome in preterm neonates-a retrospective analysis.

BACKGROUND: Prematurity is associated with increased risk for morbidity and mortality. Aim of this study was to evaluate whether cerebral oxygenation during fetal-to-neonatal transition period was associated with long-term outcome in very preterm neonates.

METHODS: Preterm neonates ≤ 32 weeks of gestation and/or ≤ 1500 g with measurements of cerebral regional oxygen saturation (crSO2 ) and cerebral fractional tissue oxygen extraction (cFTOE) within the first 15 min after birth were analysed retrospectively. Arterial oxygen saturation (SpO2 ) and heart rate (HR) were measured with pulse oximetry. Long-term outcome was assessed at two years using "Bayley Scales of Infant Development" (BSID-II/III). Included preterm neonates were stratified into two groups: adverse outcome group (BSID-III ≤ 70 or testing not possible due to severe cognitive impairment or mortality) or favorable outcome group (BSID-III > 70). As the association between gestational age and long-term outcome is well known, correction for gestational age might disguise the potential association between crSO2 and neurodevelopmental impairment. Therefore, due to an explorative approach the two groups were compared without correction for gestational age.

RESULTS: Forty-two preterm neonates were included: adverse outcome group n = 13; favorable outcome group n = 29. Median(IQR) gestational age and birth weight were 24.8 weeks (24.2-29.8) and 760 g (670-1054) in adverse outcome group and 30.6 weeks (28.1-32.0) (p = 0.009*) and 1250 g (972-1390) (p = 0.001*) in the favorable outcome group, respectively. crSO2 was lower (significant in 10 out of 14 min) and cFTOE higher in adverse outcome group. There were no difference in SpO2 , HR and fraction of inspired oxygen (FiO2 ), except for FiO2 in minute 11, with higher FiO2 in the adverse outcome group.

CONCLUSION: Preterm neonates with adverse outcome had beside lower gestational age also a lower crSO2 during immediate fetal-to-neonatal transition when compared to preterm neonates with age appropriate outcome. Lower gestational age in the adverse outcome group would suggest beside lower crSO2 also lower SpO2 and HR in this group, which were however similar in both groups.