Pulmonary interstitial emphysema (PIE) occurs when abnormal collections of air develop within the lungs. The small airways and terminal sac rupture but instead of the rupturing into the chest cavity to produce a pneumothorax the small amounts of air are trapped within the lung itself air. PIE is more frequent in premature infants who require mechanical ventilation for severe lung disease such as respiratory distress syndrome. PIE may also lead to air leaks and tension pneumothorax, once PIE is diagnosed, intensive respiratory management is required because the trapped air makes the lung very stiff and greatly inhibits gas exchange. PIE occurs less frequently as premature babies are now treated with exogenous surfactant, which helps to keep the lungs open. Babies with PIE often require long-term ventilator therapy and many develop bronchopulmonary dysplasia (BPD).
Treatment is difficult and may include