Persistent interstitial pulmonary emphysema: another complication of the respiratory distress syndrome.

Persistent interstitial pulmonary emphysema (PIPE) was observed in 22 infants during the neonatal period. All of the infants experienced respiratory distress during the first few days of life, and 21 of them were treated for the respiratory distress syndrome with artificial ventilation or oxygen or both. Ten infants developed a localized form of PIPE, with air-filled interstitial cysts measuring up to 3.0 cm in diameter confined to one or more lobes of lung. The involved segment of lung was resected in seven of these infants, all of whom survived. The remaining three died and autopsies were performed. A diffuse form of PIPE was observed in the other 12 infants. Numerous cysts that were predominantly small (less than 0.3 cm) were seen in all lobes of both lungs. These infants received high concentrations of oxygen for prolonged periods, resulting in bronchopulmonary dysplasia in 11 of the infants. All 12 infants died. PIPE is characterized histologically by air-filled interstitial cysts partially lined by multi-nucleated giant cells.