Use of surfactant in the prevention and treatment of neonatal respiratory distress syndrome.

The rationale for surfactant therapy in premature infants is presented, along with a discussion of the characteristics of surfactant and a review of clinical trials of surfactant for the prevention and treatment of neonatal respiratory distress syndrome (RDS). RDS is a major complication of prematurity, affecting up to 40,000 infants in the United States and Canada annually. Poor lung compliance due to a functional or quantitative deficiency of surfactant causes progressive collapse of the lungs. Surfactant, a mixture of phospholipids, neutral lipids, and proteins synthesized by pneumocytes during gestation, reduces surface tension and stabilizes alveoli, which increases lung compliance and decreases the work of breathing. Mammalian, human, and artificial surfactants are being investigated for use in premature infants. Several controlled trials of exogenous surfactant therapy have demonstrated reductions in mortality and pulmonary air-leak phenomena and improved gas exchange, but these results are not seen consistently, and no significant reductions in bronchopulmonary dysplasia have been observed. Surfactant has no appreciable toxicity, although the potential for immunogenicity exists. Typical doses range from 60 mg to 200 mg/kg administered endotracheally either before the first breath or after development of RDS. Surfactant is a safe investigational agent that appears promising for the prevention and treatment of neonatal RDS, although additional clinical trials with long-term follow-up are needed to determine its true efficacy.