055 - Is Permissive Hypercapnia Associated With the Development of Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Preterm Infants ?

Publication Number: 55.5840

Kulsajan S. Bhatia, University of Alabama School of Medicine, Bimringham, AL, United States; Abinash Nayak, University of Alabama at Birmingham, Birmingham, AL, United States; Colm P. Travers, UAB, Birmingham, AL, United States; Seabrook Jeffcoat, University of Alabama at Birmingham, Birmingham, AL, United States; Waldemar Carlo, UAB School of Medicine, Birmingham, AL, United States; Namasivayam Ambalavanan, University of Alabama School of Medicine, Birmingham, AL, United States; Samuel Gentle, Yale School of Medicine, Guilford, CT, United States

Background: Whereas data suggests that carbon dioxide (CO2) and pH impact pulmonary vascular resistance in acute forms of pulmonary hypertension (e.g. persistent pulmonary hypertension in term infants), less is known regarding the impact of these factors on the development of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH).

Objective: We hypothesized that infants that developed BPD-PH would achieve a higher CO2 distribution over the first postnatal month as compared to infants that developed BPD alone

Design/Methods: We conducted a retrospective cohort study between 2017 and 2024 in infants born at < 29 weeks’ gestation, exposed to invasive mechanical ventilation, and who later developed BPD. Based on baseline differences between groups, infants were propensity score matched using gestational age, birth weight, and race. Achieved transcutaneous CO2 levels were compared between infants who developed BPD alone and infants who developed BPD-PH while on invasive mechanical ventilation. To analyze nonlinear trends in transcutaneous CO2 levels over time, the R splinectomeR package was used to test for an overall significant difference between groups summary splines by postnatal age for (1) pulmonary hypertension status and (2) mortality among infants with BPD-PH.

Results: A total of 220 infants were included for analysis, 110 of which had BPD and 110 with BPD-PH. Covariates that differed between groups following propensity score matching included, BPD grade, corticosteroid exposure, and mortality (Table 1). Differences in CO2 over time approached significance by BPD-PH status (p=0.05; Figure 1, Panel A) and were nonsignificant by mortality among infants with BPD-PH (p=0.86; Figure 1, Panel B).

Conclusion(s): Longitudinal analysis of transcutaneous CO2 levels over the first postnatal month approached significance by BPD-PH status. Further research is needed to explore whether CO2 modulates risk for BPD-PH.

Table 1: Propensity score matched data for demographic and clinical variables.
Table 1: Propensity score matched data for demographic and clinical variables.

Figure 1. Splines of TCO2 values depicting longitudinal trends in TCO2 values over the first postnatal month by BPD-PH status (Panel A) and survival status in infants with established BPD-PH (Panel B). There was no difference in TCO2 values over time by BPD-PH status (p=0.05) or survival status in infants with established BPD-PH (p=0.86). TCO2:transcutaneous carbon dioxide, BPD: bronchopulmonary dysplasia.
Figure 1. Splines of TCO2 values depicting longitudinal trends in TCO2 values over the first postnatal month by BPD-PH status (Panel A) and survival status in infants with established BPD-PH (Panel B). There was no difference in TCO2 values over time by BPD-PH status (p=0.05) or survival status in infants with established BPD-PH (p=0.86). TCO2:transcutaneous carbon dioxide, BPD: bronchopulmonary dysplasia.