We hypothesize that infants who were born prematurely but are clinically without chronic respiratory disease have a lower lung diffusion capacity than healthy infants born at full term, when evaluated at comparable post-conception ages. In addition, prematurely born infants that develop chronic lung disease have an even lower diffusion capacity than healthy premature infants and full term infants. A lower diffusion capacity, when normalized to lung volume, would be consistent with decreased alveolarization and alveolar surface area in the infants born prematurely. We will study the age range of 1 to 24 month as this represents the period of rapid lung growth.
