Brain and renal oxygenation measured by NIRS related to patent ductus arteriosus in preterm infants: a prospective observational study

BACKGROUND: Patent ductus arteriosus (PDA) is common among preterm neonates. Haemodynamically significant ductus arteriosus (hsPDA) can cause ductal steal and contribute to poor outcomes. Our aim was to evaluate ductus arteriosus patency and significance using two-site near-infrared spectroscopy (NIRS) measurements in preterm infants older than 72 h as a supplemental tool to echocardiography. METHODS: In this prospective observational study, 123 preterm infants (gestational age (GA) < 32 weeks, birth weight < 1500 g) were enrolled. Sixty-four newborns had closed ductus arteriosus (noPDA), and 41 and 18 patients were assigned to the PDA and hsPDA groups, respectively, per predefined echocardiographic criteria. Cerebral and renal oxygenation were assessed during NIRS monitoring. RESULTS: A higher renal mean (±SD) regional tissue oxygen saturation (rSpO(2)) (76.7 (±7.64)) was detected in the noPDA group than in the PDA (71.7 (±9.02)) and hsPDA (67.4 (±13.48)) groups (p < 0.001). Renal fractional tissue oxygen extraction (FTOE) (0.18 (±0.079)) was lower in the noPDA group than in the PDA (0.23 (±0.092)) and hsPDA (0.24 (±0.117))0.117 groups (p = 0.002). Cerebral oxygenation was significantly lower in the hsPDA group (77.0 (±5.16)) than in the noPDA (79.3 (±2.45)) and PDA (79.7 (±2.27)) groups (p = 0.004). There was no significant difference in cerebral fractional tissue oxygen extraction (FTOE) between any of the groups. CONCLUSIONS: Our results suggest that renal oxygenation is affected by ductus patency in preterm infants older than 72 h. Significant differences in cerebral oxygenation were observed between the hsPDA group and the PDA and noPDA groups. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04295395. Registration date: 4 March 2020. This study was retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04295395.