367 - First 72 Hours Of Pulmonary Compliance and Bronchopulmonary Dysplasia Severity in Preterm Infants

Publication Number: 1351.367

Raima Hashmi, Hurley Medical Center, Michigan State University, grand blanc, MI, United States; Adenike O.. Fatiregun, Hurley Medical Center, Michigan State University, Flint, MI, United States; Navin Kumar, Hurley Medical Center , Michigan state University, Flint, MI, United States

Background: Bronchopulmonary dysplasia (BPD) remains a major morbidity in preterm infants. Early pulmonary status, quantified by dynamic lung compliance, may be a key predictor of BPD severity, but its longitudinal profile and predictive value are not well characterized.

Objective: To determine the association between early dynamic lung compliance profiles in the first 72 hours of life and the subsequent severity of BPD in preterm infants.

Design/Methods: In this retrospective cohort study (2016-2022), we analyzed 99 infants born at ≤32 weeks' gestation who received conventional mechanical ventilation. Dynamic lung compliance (mL/cmH2O/kg) was captured minute-by-minute from ventilators. From approximately 2.8 million data points, we derived four key metrics per infant: 1) Initial Compliance (median value in the first post-intubation hour); 2) Estimated Initial Compliance (intercept from a regression model of all 72-hour data); 3) Compliance Trend (slope from the same regression, representing the; and 4) Early Proportional Change (percentage change over the first 24 hours). The primary outcome was BPD severity at 36 weeks' PMA (none, mild, moderate/severe by Jenson criteria). Associations were evaluated using 4 generalized ordered logit models [Table 1], adjusting for confounders including gestational age, sepsis, and maternal infection.

Results: The cohort (median GA 27 weeks; median BW 1069g) showed significant associations in unadjusted analyses: a lower 72-hour compliance slope and diminished 24-hour improvement were strongly associated with greater BPD severity (p < 0.001) [Fig 1]. Adjusted models confirmed that a more positive 72-hour compliance slope (aOR 0.35, 95% CI 0.21-0.59) and a greater 24-hour proportional improvement (aOR 0.31, 95% CI 0.16-0.60) were independently protective against progression to moderate/severe BPD. Model-predicted probabilities for moderate/severe BPD were plotted against these dynamics [Fig 2]. Conversely, a higher initial compliance in the first hour was associated with increased odds of moderate/severe BPD (aOR 1.74, 95% CI 1.03-2.92). Lower gestational age, maternal infection, and sepsis were consistently significant risk factors.[Table 1]

Conclusion(s): The trajectory of early lung compliance, specifically a positive rate of change and proportional improvement within the first days of life, is a strong independent predictor of protection against more severe BPD. In contrast, higher initial compliance may reflect early stretchability and subsequent vulnerability to lung injury. Monitoring early continuous compliance dynamics may offer valuable prognostic insight.

Table 1: Differential Associations of Predictors with BPD Severity (Jenson criteria) from Generalized Ordered Logit Models.
Notes: Models show aOR = Adjusted Odds Ratio with 95% confidence intervals in brackets, N = 99 for all models. +p < 0.1, * p<0.05, ** p<0.01, *** p<0.001.GA = Gestational Age; PDA = Patent Ductus Arteriosus; BMZ = Betamethasone.

Figure 1.Predicted Probability of Moderate-Severe BPD Across Gestational Age Groups (Jensen Criteria) Using Compliance Slopes within the 1st 72 Hours of Life.


Figure 2. Compliance Profiles by BPD Severity (Jensen Criteria) Univariate Analysis.