Naturally produced in the lungs by cells called pneumocytes, this substance is a mixture of phospholipids and lipoproteins. Present in fluid lining the alveoli in the lungs, their action helps keep them open, rather than sticking together, particularly after breathing out. Premature babies may have a deficiency of surfactant, a disorder which causes severe breathing difficulties respiratory distress syndrome or hyaline membrane disease and hypoxia. They may need urgent respiratory support, which includes oxygen, artificial ventilation and the administration (via an endotracheal tube) of a specially prepared surfactant such as beractant (bovine lung extract) or edfosceril palmitate.
A lipoprotein secreted by type II alveolar cells that decreases the surface tension of the fluid lining the alveoli, permitting expansion. Synthetic lung surfactant is available tor treating patients with respiratory distress syndrome. In obstetrics, fetal production of surfactant can be stimulated by administration of a glucocorticoid 24 to 48 hr before an inevitable preterm birth.