Changes in fatty acids in phospholipids of the bronchoalveolar fluid in bacterial pneumonia and in adult respiratory distress syndrome.

Fatty acids of the phospholipid fraction of bronchoalveolar lavage fluid from patients with bacterial pneumonia or with the adult respiratory distress syndrome were chromatographed and the patterns compared with those for a control group. In the control group, palmitic acid (16:0) was the predominant fatty acid, accounting for 58.0% (SD 8.25%) of the total fatty acid, a proportion significantly higher (p less than 0.001) than in the distress-syndrome group (42.1%, SD 4.88%) or the acute pneumonia group (32.1%, SD 1.73%). There was a greater proportion of oleic acid (18:1) in the disease groups; thus the ratio of palmitic to oleic acid was useful in distinguishing these three groups. No patient with a palmitic/oleic acid ratio greater than 2.45 had evidence of parenchymal inflammation. Of those with a ratio less than 1.3, 89% had acute bacterial pneumonia.