[The pulmonary surfactant system: physiology, pathologies associated with its alteration and exogenous administration as therapeutic and diagnostic agent].

Pulmonary surfactant is a lipoproteic mixture synthesized and secreted by alveolar type II cells. Its principal property is to reduce the surface tension by lining on the alveolar surface. Surfactant deficiency is the major factor responsible for the respiratory distress syndrome of the newborn (RDS) and the adult respiratory distress syndrome (ARDS). Since 1980, the exogenous administration of surfactant for the treatment of these syndromes is being studied. In this work the exogenous surfactant preparations, the delivery techniques and the dosing schedule is discussed. The utilization of the exogenous natural surfactant (ENS) as precursor of a radiopharmaceutical labeled with 99mTc (99mTc-ENS) for aerial lung scintigraphy is also discussed.