SURFACTANT FUNCTION IN NEONATES WITH RESPIRATORY-DISTRESS SYNDROME

The function of pulmonary surfactant of a group of 14 preterm neonates (birth weight 907 +/- 60 g) who suffered from severe respiratory dist ress syndrome (RDS) and who had received exogenous bovine lipid extrac ted surfactant on the first day of life was compared to that in a seco nd group of 8 neonates (birth weight 940 +/- 110 g) with mild RDS who had not received surfactant treatment. Mechanical respiratory support from day 2 on was the same in both groups. The minimal surface tension (gamma(min)) improved steadily, falling from about 30 mN/m initially to less than 20 mN/m before extubation, A consistent but loose correla tion was found between gamma(min) and mechanical respiratory support n ecessary, as quantitated by the oxygenation index. Total protein was a bout 0.8 +/- 0.2 mg/mg of phospholipids and did not change during the first week of life. There were no correlations between total protein a nd gamma(min) or the oxygenation index. The data suggest that inhibiti on of surfactant function by proteins leaked into the airspaces does n ot play a major role during recovery from RDS, Instead, endogenous rem odelling of surfactant might be of greater relevance.