Microviscosity of tracheal aspirates in newborns with respiratory distress.

The microviscosity of tracheal aspirates from newborn children with respiratory problems was investigated using fluorescence polarization. The pulmonary status of 100 newborns with hyaline membrane disease (HMD) and a reference group (n = 45) was assessed daily throughout of intubation. Two main changes in phospholipid microviscosity (eta) were identified. A decrease in eta associated with a favourable clinical outcome. A dramatic increase in eta with an unfavourable outcome in pulmonary function. These changes correlated with clinical observations, but the trends in microviscosity seemed to appear before any related clinical sign. It is proposed that the measurement of tracheal microviscosity provides a method for checking pulmonary function in the first days of life. The method is rapid and sensitive; it detects small variations barely detectable using more conventional ways by which pulmonary phospholipids are usually studied.