237 - The Use of Early Continuous Cerebral NIRS Monitoring to Predict Hemodynamically Significant Patent Ductus Arteriosus in Extremely Premature Infants

Patent Ductus Arteriosus (PDA) is common in extremely premature infants, affecting approximately 70% of 23-24-week gestational age (GA) infants, and 59% of 25-28-week GA infants. Hemodynamically significant PDA (hsPDA) is associated with increased mortality, pulmonary morbidities, prolonged need for mechanical ventilation, bronchopulmonary dysplasia, necrotizing enterocolitis and intraventricular hemorrhage (IVH). A potential mechanism of this association is the ductal steal phenomenon where blood shifts from the left side of circulation to the right side, leading to pulmonary hyperperfusion and systemic hypoperfusion including cerebral hypoperfusion.

Objective: The aim of this study was to illustrate whether the clinical use of continuous cerebral NIRS monitoring in the first few days of life can delineate between infants with hsPDA and infants without hsPDA.

Design/Methods:

This retrospective study took place at the Brigham and Women’s hospital between 2018 and 2020. At our institution, beginning January 1st, 2018, all infants born before 28 weeks GA were monitored clinically with a commercially available NIRS monitor (INOVS) for at least the first 3 days of life. HsPDA was classified based on presence of PDA by echocardiogram that required medical or surgical treatment. Patients with and without hsPDA were compared regarding the cerebral saturation (rSO₂) mean, median, standard deviation (SD), coefficient of variation (CV) and Inter-Quartile Values (IQ). JMP Pro version 15.2.0 was used for statistical analyses.

Results: 96 infants out of 117 infants were included in this analysis. Infants were excluded from the analysis if the NIRS data was not available (n = 8), if the measurement was less than 6 hours (n = 2), or if the infant passed away before being evaluated/treated for PDA (n =11). The mean GA of the study population was 25.9 weeks +/- 1.3 and the mean birth weight was 0.81 kg +/- 0.19.  55 (57%) had hsPDA and 41 (43%) had either no PDA or non-significant PDA not requiring treatment. Overall, the mean and median cerebral rSO₂ values did not differ between the groups (t-test, p = 0.50 or 0.61, respectively). Infants with hsPDA had significantly higher rSO₂ SD, CV, and IQR values (t-test, p = 0.02, 0.02, or 0.01, respectively, Figure 1).

Conclusion(s): Infants with hsPDA had higher rSO₂ variability during the first 3 days of life. These results suggest that fluctuating flow through the ductus might be predicted by oscillations in the cerebral rSO₂ values detected by early NIRS. Future work: improved temporal resolution, confounding variables (IVH, hematocrit), stricter definition of hsPDA.