[Analysis of dipalmitoyl-phosphatidyl-choline (DPPC) in amniotic fluid: a new sensitive method for surfactant determination].

The surface active alveolar system (surfactant) is of central importance for normal lung function in newborn infants and its lack remains a frequent cause of perinatal mortality and morbidity in premature infants, as well as those born at term. The most important substance of this system is the lecithin dipalmitoyl-phosphatidyl-choline (DPPC). Many different methods to obtain information concerning lung maturity through analysis of phospholipids in the amniotic fluid have been tested, but all of them give only indirect assessment of the DPPC content. A new method for the separation and quantification of DPPC and the other lecithins in amniotic fluids is presented. This capillary gas-chromatographic procedure enabled a comparison of these parameters with the postpartum pulmonary condition of the newborn infants. It was found that the di-saturated lecithin PC 30 increases with increasing lung maturity and plays a major role in the surfactant complex, together with DPPC and PC 34, which are inter-related. Of all chemical methods for analysis of amniotic fluid, gas-chromatographic determination of the concentration of DPPC and PC 30 constitutes the best parameter for prediction of fetal lung maturity.