Comparison of pharyngeal aspirate and amniotic fluid surfactant composition

Amniotic fluid and oropharyngeal aspirate lung maturity profiles obtained simultaneously at delivery in 16 patients are compared. The lecithin/sphingomyelin ratio was greater in oropharyngeal aspirates than in amniotic fluid (p less than 0.02). The percent phosphatidylinositol was greater in oropharyngeal aspirates than in amniotic fluid (p less than 0.03). The mean differences between percent phosphatidylglycerol were not significant. These findings were uninfluenced by the time interval between amniotic fluid and oropharyngeal sampling, gestational age, or neonatal weight. These data could explain the lack of sensitivity of the amniotic fluid lung maturity profile.