The changing pattern of chronic lung disease of prematurity.

Thirty four infants with chronic lung disease of prematurity were reviewed and divided into two groups on the appearance of the chest radiograph. Type 1 disease (n = 19) was defined as homogeneous or patchy ill defined opacification in the lungs without coarse reticulation, and type 2 disease (n = 11) had the classical appearance of bronchopulmonary dysplasia. Four patients could not be classified. We conclude that type 1 disease represents typical chronic lung disease of premature infants, and type 2 is usually complicated by pulmonary interstitial emphysema. As no infant with type 1 disease died, its histopathological basis is unknown.