Fluorescence anisotropy of tracheal and oropharyngeal aspirates as an indicator of lung disease in neonates.

Fluorescence anisotropy was assessed in tracheal and oropharyngeal aspirates to evaluate its use in the diagnosis of respiratory distress syndrome. Samples from 31 neonates at birth were purified by using Sephacryl S-300 column chromatography. After the addition of the molecular probe, 1,6-diphenyl 1,3,5 hexatriene fluorescence was measured and anisotropy calculated. Ten neonates with normal respiratory function had a mean anisotropy (+/- SD) of 0.226 +/- 0.023. Fourteen infants with a diagnosis of respiratory distress syndrome had a mean anisotropy of 0.260 +/- 0.014 (p < 0.001). Seven neonates with respiratory problems other than respiratory distress syndrome had a mean anisotropy of 0.211 +/- 0.027 (p < 0.001 vs respiratory distress syndrome). A diagnosis of respiratory distress syndrome was associated with higher tracheal fluid anisotropy, indicating a qualitative difference in the characteristics of the pulmonary surfactant. We conclude that this 30-minute test could help identify neonates who benefit from surfactant replacement therapy.