[The exogenous surfactant and its effect on the respiratory distress syndrome (RDS)].

In this article the pathophysiology and diagnosis of neonatal respiratory distress syndrome as a primarily form of surfactant deficiency is disclosed. Attention is paid to surfactant composition, productive and secretion in the alveoli and metabolic turnover as well. From clinical point the view basic principles concerning the surfactant replacement is discussed. Surfactant minimizes the surface tension and friction between the gas molecules and lung tissues during breathing. It also helps keep lung tissues dry and alveoli patent. At 26 to 28 weeks of gestation alveolar ducts and bronchioles are present but pulmonary capillaries are not in close contact with them. Alveoli may not even be distinguishable. Surfactant develops all through gestation but does not surge until about the 34th week. Infants born before 35 weeks of gestation are at risk for respiratory distress syndrome which is at first characterised by decrease of lung compliance. It leads to progressive respiratory failure.