Increased prevalence of expiratory flow limitation during exercise in children with bronchopulmonary dysplasia

Area of Science:

• Pediatric Pulmonology
• Exercise Physiology
• Neonatology

Background:

• Limited evidence exists on exercise-induced expiratory flow limitation (EFL) and ventilatory responses in preterm children.
• Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting preterm infants, potentially impacting exercise capacity.

Purpose of the Study:

• To determine the prevalence of EFL during exercise in preterm children with and without BPD.
• To identify factors contributing to EFL in this population.
• To assess ventilatory responses to exercise in preterm children with and without BPD compared to term controls.

Main Methods:

• An incremental treadmill exercise test was conducted on preterm children (≤32 weeks gestational age, 9-12 years) with (n=64) and without (n=42) BPD, and term controls (n=43).
• Exercise tidal flow-volume loops were analyzed to detect EFL.
• Peak oxygen uptake and tidal volume at peak exercise were measured.

Main Results:

• Expiratory flow limitation (EFL) was more prevalent in preterm children with BPD (53%) compared to those without BPD (26%) and term controls (28%).
• EFL was independently associated with reduced forced expiratory volume in 1-second/forced vital capacity z-scores and lower gestational age.
• Children with BPD showed a lower tidal volume at peak exercise, though peak oxygen uptake was similar to term controls.

Conclusions:

• Expiratory flow limitation is significantly more prevalent in preterm children with BPD.
• EFL in this group is associated with airway obstruction and lower gestational age.
• Preterm children without BPD exhibited similar exercise ventilatory responses to term controls.