Acquired lobar emphysema (overinflation): Clinical and pathological evaluation of infants requiring lobectomy

Acquired lobar “emphysema” (overinflation) (ALE) is an increasingly recognized complication of advanced bronchopulmonary dysplasia (BPD). To refine current concepts regarding patient management and pathogenesis, we examined clinical and pathological features of six infants with ALE who did not have obstructing intraluminal lesions and who underwent lobectomy after failing nonoperative management. All had severe neonatal respiratory distress and required prolonged ventilatory support (average, 2 months) with peak inspiratory pressures greater than 30 mm Hg and 100% oxygen. ALE developed between 3 weeks and 20 months of age (median, 5 months), with lobar hyperinflation, atelectasis, and mediastinal shift. Selective bronchial intubation provided only transient benefit. Videobronchoscopy demonstrated no intraluminal obstructing lesions in five patients. In one child, ALE became clinically apparent only after laser excision of an endobronchial cicatrix. All infants had bronchomalacia with the involved lobar bronchus being most severely affected. Ventilation-perfusion scans demonstrated severe impairment of both ventilation and perfusion in the invoved lobes. The decision to perform lobectomy was based on clinical parameters and failure of non-operative management. After lobectomy, all children dramatically improved. However, only three of six were alive 2 to 3 years later; one infant died of unrelated causes at 6 weeks; and two died of progressive respiratory insufficiency 13 and 24 months postlobectomy. Microscopic evaluation of the lung demonstrated findings of late-stage BPD with peribronchial and interstitial fibrosis, parenchymal overinflation, and alveolar septal disruption. Morphometric studies, compared with age-matched autopsy controls, showed no appreciable differences in the amount of bronchial cartilage, internal luminal area, or mean cartilage per wall area. There is no evidence of a quantitative deficiency of bronchial cartilage or diminished luminal area and morphologic features corresponded poorly to demonstrable airway collapse. Qualitative airway abnormalities may be responsible for the severity of the localized bronchomalacia. This study demonstrates that severe bronchomalacia of a lobar bronchus is associated with ALE in infants with advanced BPD. Although lobectomy is initially effective for selected patients, late death from BPD occurs in a substantial number of children.