Bubbles in hyaline membrane disease. Differentiation of three types.

Three types of bubbles can be radiographically identified in hyaline membrane disease (HMD). The first type, seen in the early acute phase, represents overdistended terminal bronchioles and alveolar ducts. Type II represents pulmonary interstitial emphysema, and is related to positive pressure assisted ventilation. Type III represents focally distended alveolar groups in a scarred, immature lung, and occurs in the chronic stages of HMD. An understanding of the three types of bubbles aids in the management of HMD.