"Acquired" lobar emphysema: a complication of respiratory distress in premature infants.

Ten premature infants with respiratory distress developed a type of pulmonary lobar emphysema that is clinically and histologically distinct from interstitial or congenital lobar emphysema. In eight patients emphysema was noted in the right lower lobe, while in two the left upper lobe was affected. Five infants exhibited nonresolution of the emphysema and an inability to be weaned from ventilator support. Lung scans in these five infants showed absent or markedly decreased perfusion of the involved lobe. Lobectomy was necessary. Postoperatively, their respiratory status improved and they were successfully weaned from the ventilator. Five premature infants with identical radiographic emphysematous changes had normal lung scans. These infants did not require lobectomy and were also successfully weaned from the ventilator. Radiographic changes of lobar emphysema in these five infants completely resolved. Pathologic changes in the excised lobes were characteristic of bronchopulmonary dysplasia and obstructive intraalveolar emphysema. The long-term effects of positive pressure ventilation, oxygen, and suctioning techniques directed toward the right lower lobe may play an important role in the etiology of "acquired" lobar emphysema.