Oxygen plus pressure plus time: the etiology of bronchopulmonary dysplasia.

Ten infants developed the chronic pulmonary syndrome designated bronchopulmonary dysplasia, following artificial (assisted) ventilation using a volume-regulated positive-pressure respirator. Despite previous reports implicating elevated oxygen concentrations for prolonged periods of time, only two infants required more than 80% oxygen for more than 24 hours, and only one infant required 60% oxygen for more than 100 hours. "Immature" lungs when exposed to inspired oxygen concentrations over 40% for as little as three days via positive-pressure ventilation may develop bronchopulmonary dysplasia. The role of the underlying disease and the relationship with Wilson-Mikity syndrome remain uncertain.