Surfactant phospholipids and surface activity among preterm infants with respiratory distress syndrome who develop bronchopulmonary dysplasia.

Our objective was to determine if preterm infants with respiratory distress syndrome who develop bronchopulmonary dysplasia have abnormalities in surfactant phospholipids and/or function. Tracheal aspirate samples obtained from preterm infants with respiratory distress syndrome on days 1, 3-5, 7-10, 14-17, 21-24 and 27-30 were analyzed for total phospholipids and phospholipids fractions by determination of total phospholipid phosphorus and thin layer chromatography, respectively. Surfactant properties were assessed with captive bubble surfactometer. Sixteen out of 56 (29%) infants died during the first 30 d of life. Infants who died were more immature, required more ventilatory support and had a surfactant with lower surface-tension-reducing properties than infants who survived (p < 0.05). Surviving infants were divided into group I (no bronchopulmonary dysplasia at 27-30 d, n = 25) and group II (with bronchopulmonary dysplasia at 27-30 d, n = 15). No significant differences in concentrations of surfactant phospholipids nor measurements of surface tension were noted among groups of infants. Surfactant therapy after birth was associated with a significant increase in concentrations of total phospholipids, lecithin, phosphatidylinositol and lower surface-tension measurements at 3-5 d of age among surviving infants (p < 0.01). Abnormalities in concentrations of surfactant phospholipids or surfactant function could not be demonstrated during the first month of life among preterm infants with respiratory distress syndrome who develop bronchopulmonary dysplasia.