378 - Differential Regional Lung Oxygenation in Preterm Infants Using Near-infrared Spectroscopy (NIRS) and the Role of Patent Ductus Arteriosus (PDA)

Publication Number: 378.4540

Ivonne E. Sierra-Strum, Children's Hospital Los Angeles, Los Angeles, CA, United States; Manoj Biniwale, Cedars Sinai Medical Center, Los Angeles, CA, United States; Piyawat Arichai, Children's Hospital Los Angeles, Pasadena, CA, United States; Rangasamy Ramanathan, Cedars Sinai Guerin Children's, Cedars Sinai Medical Center, Los angeles, CA, United States

Background: Premature infants are at high risk of hypoxemia during early postnatal transition. Regional lung oxygenation differences measured by Near-Infrared Spectroscopy (NIRS) and the impact of Patent Ductus Arteriosus (PDA) on these differences remain unexplored

Objective: We compared regional differences in oxygenation between the right lung (RrpSO2) and left lung (LrpSO2) using NIRS in preterm infants receiving invasive and noninvasive ventilation. We examined the relationship between hemodynamic significant PDA (hsPDA) and observed differences in lung oxygenation

Design/Methods: This study involved preterm infants with respiratory distress syndrome (RDS) on noninvasive or invasive respiratory support. Continuous monitoring of RrpSO₂ and LrpSO₂ was performed over 12 hrs. hsPDA was defined as ductal diameter >1.5 mm, LA:Ao ≥1.4, diastolic flow reversal in the descending aorta, and LPA end-diastolic velocity ≥20 cm/sec. Differences between RrpSO₂ and LrpSO₂ were analyzed in relation to hsPDA presence using a paired T-test

Results: Of the 30 infants, 60% were male (n = 18). Mean gestational age was 28.7 ± 2.1 weeks, and mean birthweight was 1,263 ± 402 grams. RrpSO₂ ranged from 66.00 to 83.69 (mean 73.56 ± 5.03, SEM 0.92), while LrpSO₂ ranged from 63.50 to 79.33 (mean 71.04 ± 5.10, SEM 0.93) (Table 1). RrpSO₂ was higher than LrpSO₂ across all time points (p < 0.0001), with a mean difference of -2.52 (95% CI: -4.14 to -1.79). In infants with hsPDA, RrpSO₂ values were higher than LrpSO₂, with more pronounced differences than those without hsPDA. Mean differences in infants with hsPDA ranged from -1.82 to -3.65 (SD 1.81 to 2.96, SEM 0.44 to 0.78), with p < 0.0001. Infants without hsPDA showed smaller but statistically significant differences, averaging -1.52 (95% CI: -2.89 to -0.88, p = 0.0032). In infants who received surfactant, the difference between RrpSO₂ and LrpSO₂ was even more pronounced, with consistently higher RrpSO₂. Although this trend was not statistically significant, the mean difference increased to -3.10 (95% CI: -5.25 to -0.95, p = 0.09)

Conclusion(s): Significant differences were observed between RrpSO₂ and LrpSO₂, with RrpSO₂ showing higher oxygenation, indicating regional variations. The presence of hsPDA appeared to amplify these disparities, likely due to altered blood flow. In infants receiving surfactant, anatomical factors related to administration may have further enhanced regional differences. Additional studies are needed to confirm our findings with a larger sample size and evaluate the impact of hsPDA on regional lung oxygenation

Mean ± (SD) of RrpSO2, LrpSO2, Right and Left Pulmonary Oxygen Extraction Fraction (FOEL) During Time Points
RrpSO2(Right Lung Regional Pulmonary Oxygen Saturation), LrpSO2 (Left Lung Regional Pulmonary Oxygen Saturation)