Pulmonary surfactant in newborn infants and children

Abstract

Pulmonary surfactant is a complex mixture of specific lipids, proteins and carbohydrates, which is produced in the lungs by type II alveolar epithelial cells. The mixture is surface active and acts to decrease surface tension at the air-liquid interface of the alveoli. The presence of such molecules with surface activity had been suspected since the early 1900s and was finally confirmed in the mid-1900s. Since then, the chemical, physical and biological properties of the surfactant mixture have been revealed due to the work of several groups of investigators. The surfactant mixture is an essential group of molecules to support air breathing. Thus, preterm infants, who are born with immature lungs and are surfactant deficient, develop respiratory distress syndrome after being born. Replacement of natural surfactant therapy with purified surfactant from lungs of nonhuman species is one of the most significant advances in neonatology and has resulted in improved limits of viability of preterm infants. Although preterm infants are the primary population, exogenous surfactant treatment may also have a role to play in other respiratory diseases of term-born infants and older children.