Endobronchial surface active phospholipids in various pulmonary diseases.

In the present study we investigated the phospholipid composition of small-volume (up to 20 ml) in vivo bronchoalveolar lavage and that of quantitative ex vivo bronchoalveolar lavage. Furthermore, the accuracy of the small-volume lavage in predicting lung disease was evaluated. There was a positive linear correlation (r approximately equal to 0.87-0.91) between the amount of saturated phosphatidylcholine and the saturated phosphatidylcholine/sphingomyelin ratio in quantitative bronchoalveolar lavage. The phospholipid distributions in the small-volume lavage and the quantitative lavage were similar (r approximately equal to 0.78-0.94, n = 14). The overall accuracy of phosphatidylcholine/sphingomyelin ratio and phosphatidylglycerol/total phospholipid ratio in predicting the presence or absence of respiratory failure was 85-87% in newborns, children, and adults. In respiratory diseases without respiratory failure, the abnormalities in the phospholipids were frequent, although less distinct. According to animal experiments the surfactant system is inhibited at the onset of high permeability lung edema. Soon thereafter, the lavageable surfactant pool is decreased. Present findings support the view that surfactant defects are of importance in the pathogenesis of respiratory disease, and that surfactant-oriented therapy may be effective in the treatment and prevention of respiratory failure.