ABSTRACT
Airway injury with subsequent dysfunction is a hallmark of bronchopulmonary dysplasia (BPD). Although the conducting airways are formed well in advance of fetal viability, they must still undergo significant maturational changes in late gestation. Until they attain characteristics of more mature airways, they are more susceptible to damage. Controversy continues to exist concerning the pathogenesis of BPD in the neonate; however, prolonged mechanical ventilation and oxygen toxicity appear to be major factors. Serial assessments of pulmonary function during the first year of life in infants with BPD have indicated that the duration and pressures of mechanical ventilation, rather than increased inspired oxygen tensions, damage the airways and interfere with their growth (1,2). Within this context, greater assisted ventilatory requirements of the very premature infant relative to the older infant yield an age-related predisposition for airway damage. The present chapter will summarize morphology and functional characteristics of the developing airways and the effect of mechanical ventilation on airway function. In addition, clinical assessment of airway function will be reviewed.
