Pathogenesis of respiratory failure in the preterm infant.

Respiratory failure in the preterm results from not only surfactant deficiency but also the immaturity of a number of other elements that have a structural basis. Airway, alveolar, fluid clearance, and epithelial and endothelial barrier functions also are important to lung function. Immaturities in these lung elements have identifiable adverse consequences for lung function such as pulmonary interstitial emphysema and pulmonary edema. The maturation of each of these elements appears to be achievable by agents such as corticosteroids, and maturation will result in an improved response to surfactant treatments. While surfactant treatments can improve respiratory failure by minimizing lung injury, other aspects of lung immaturity continue to contribute to respiratory compromise in the preterm. A thorough understanding of respiratory failure in the newborn depends on a better appreciation of the contribution of immaturity of the different structural elements of the lung on lung function.