Supplementary Material for: Cerebral Saturation and Fractional Tissue Oxygen Extraction Are Associated with Anterior Cerebral Artery Doppler Parameters in Neonates with Congenital Heart Defects

Introduction: To explore the relationship between near-infrared spectroscopy parameters (Cerebral Saturation [CSat] and corresponding cerebral fractional tissue oxygen extraction [cFTOE]) with Resistive (RI) and Pulsatility indices (PI) of the anterior cerebral artery (ACA) obtained simultaneously in neonates with congenital heart defect (CHD) during the first week of life.

Methods: Prospective observational study on neonates ≥35 weeks with CHD. Cerebral FTOE was based on concomitant pre-ductal oxygen saturation (SpO2) during CSat measurement. ACA was assessed via Doppler ultrasound (US). Continuous CSat/SpO2 monitoring was collected during the first week of life. Daily ACA-doppler was obtained from day 1 to 7.

Results: 142 concomitant measurements of NIRS and US parameters during the first week of life were collected in 34 neonates with various CHD. Mixed effect models showed significant association between CSat/cFTOE and time-corresponding RI-ACA (p=0.02 and 0.005) and PI-ACA (p=0.006 and 0.002), respectively. A 0.1-point increase in RI was associated to a 2.3% decrease in CSat and a 3-point increase in cFTOE. A 0.1-point increase in PI was associated to a 0.9% decrease in CSat and 1.1-point increase in cFTOE.

Conclusions: In neonates with CHD during their first week of life, lower CSat and higher cerebral FTOE were associated with elevated RI and PI values of the ACA obtained simultaneously. Future research should assess whether a multimodal bedside approach to monitoring cerebrovascular hemodynamics can facilitate early detection of cerebral hypoperfusion and prevent brain injury, as well as adverse neurodevelopmental outcomes in this vulnerable population.