OBJECTIVE

Reference values of regional cerebral oxygen saturation (rScO) in preterm neonates across gestational age (GA) groups remain undefined. This study aimed to establish rScO references for neonates born before 32 weeks of gestation.

DESIGN

A prospective observational cohort study.

SETTING

Large tertiary neonatal referral centre in Croatia.

PATIENTS

Preterm neonates without major comorbidities born between 2018 and 2022 with normal cranial ultrasound findings.

INTERVENTIONS

rScO was assessed with near-infrared spectroscopy (NIRS) using neonatal sensors.

MAIN OUTCOME MEASURES

The primary analysis provided rScO reference ranges for the entire preterm neonatal cohort, followed by stratified analyses based on GA: , <28.0 weeks; , 28.0-30.0 weeks; and , 30.1-32.0 weeks. Quantile regression was used to estimate the selected rScO percentiles (5th, 10th, 50th, 90th and 95th) from 6 to 72 hours after birth.

RESULTS

114 neonates with median (IQR) GA of 29.9 (29.1-31.5) weeks were included: 22% were EP, 29% were VP and 49% were VP. The median rScO was 75.6% at 6 hours, 79.5% over the first 24 hours and exceeding 80% in the subsequent 48 hours. When analysed separately, notable differences emerged across prematurity categories, with the highest median rScO observed in the VP group. Supplementary analyses, comparing rScO values across the three GA groups, revealed significant differences at 48 and 72 hours. The majority of the estimated rScO fifth percentiles between 6 and 72 hours were in the range ≥60%, with a single lowest estimate of 56.3% at 6 hours in the EP group. Thus, for all subgroups, the estimated fifth percentile of rScO was above the brain hypoxic threshold.

CONCLUSIONS

The use of age-appropriate neonatal NIRS sensors provided the rScO reference values for very and extremely preterm neonates without major comorbidities 6-72 hours after birth.