ARE BIOCHEMICAL PARAMETERS OF LUNG MATURATION FROM GASTRIC, TRACHEAL,AND PHARYNGEAL ASPIRATES COMPARABLE

Phospholipid parameters - lecithin/sphingomyelin (L/S) ratio and palmi tic acid/stearic acid (P/S) ratio - of gastric (GA), pharyngeal (PA), and tracheal aspirates (TA) have often been used for estimation of lun g maturation. However, it was not known whether values from different sources can be alternatively used. The study was performed to test whe ther P/S and L/S ratios in GA, PA, and TA are comparable. 11 GA, 30 PA , and 10 TA were obtained from infants within 10 min after birth. All infants were healthy, vaginally delivered with no respiratory distress , and had a gestational age greater than or equal to 34 weeks. Pattern s of fatty acids were determined by gas chromatography and the L/S rat io by high-performance liquid chromatography. We found lower L/S ratio s in GA (16.5 +/- 5.2) when compared with PA (39 +/- 16) or TA (41 +/- 15, p < 0.01); there were no differences between PA and TA. The P/S r atio was in the same range in PA and TA, but lower in GA. As compared with TA and PA, in GA the relative percentage of palmitic acid of all fatty acids was lower, the percentage of monounsaturated fatty acids, however, higher. We conclude that phospholipid parameters of lung matu ration in PA and TA, but not in GA, can be alternatively used.