474 - Early Pulmonary Compliance and its Association with Patent Ductus Arteriosus Severity in Preterm Infants

Publication Number: 3458.474

Nnamdi Nwoke, Michigan State University College of Human Medicine, Grand Blanc Township, MI, United States; Raima Hashmi, Hurley Medical Center, Michigan State University, grand blanc, MI, United States; Navin Kumar, Hurley Medical Center , Michigan state University, Flint, MI, United States

Background: The relationship between early pulmonary physiology and hemodynamically significant patent ductus arteriosus (PDA) in preterm infants remains poorly understood. Early Dynamic lung compliance may reflect cardiopulmonary interactions that predispose to PDA development, potentially serving as an early predictive marker.

Objective: To determine whether early (first 24 hours) dynamic lung compliance profiles predict subsequent echocardiographic PDA severity in very preterm infants.

Design/Methods: This retrospective cohort study analyzed 99 infants born at ≤32 weeks' gestation who required conventional mechanical ventilation (2016-2022). Dynamic lung compliance (mL/cmH₂O/kg) was captured minute-by-minute. Four compliance metrics were analyzed: initial compliance (first-hour median), estimated baseline compliance (72-hour intercept), compliance trend (72-hour slope), and early proportional change (24-hour). The primary outcome was PDA severity (no, small, moderate, large) diagnosed echocardiographically after 72 hours. Associations were assessed using generalized ordered logit models adjusting for gestational age, birth weight z-score, race, delivery mode, and prenatal steroids.

Results: Early worsening of lung compliance strongly predicted significant PDA. While higher initial compliance was associated with increased PDA risk (aOR 1.97, 95% CI 1.10-3.55), the temporal trajectory proved more revealing. Both a declining 72-hour compliance slope (aOR 0.48, 95% CI 0.30-0.77) and a negative 24-hour proportional change (aOR 0.35, 95% CI 0.20-0.62) were significantly associated with a large PDA, indicating that early compliance deterioration is a strong predictor of severe ductal disease. The compliance intercept showed particular strength for predicting moderate/large PDA (aOR 2.66, 95% CI 1.34-5.28). Lower gestational age and vaginal delivery were consistent risk factors across severity thresholds.

Conclusion(s): Early lung compliance patterns provide an independent prediction of PDA severity. The trajectory of compliance change, particularly early worsening, appears critically important for identifying infants at the highest risk for significant PDA. Monitoring dynamic compliance could enhance early risk stratification and guide timely intervention for hemodynamically significant PDA in preterm infants.

Differential Associations of Predictors with PDA Severity from Generalized Ordered Logit Models
Continuous Variables were standardized for regression analysis: Compliance variables: robust z score (change represented by 1 median absolute deviation); GA, Maternal age: classical z score( change represented by 1 Standard deviation)

Differential Associations of Predictors with PDA Severity from Generalized Ordered Logit Models
Continuous Variables were standardized for regression analysis: Compliance variables: robust z score (change represented by 1 median absolute deviation); GA, Maternal age: classical z score( change represented by 1 Standard deviation)