Surfactant aerosol treatment of respiratory distress syndrome in the spontaneously breathing premature rabbit.

Surfactant deficiency in premature neonates is a major factor in the development of respiratory distress syndrome (RDS), which is still a significant cause of mortality and morbidity. The aim of this study was to test a noninvasive method of administering surfactant as treatment for RDS. The animal model used was the premature neonatal rabbit of 27-d gestation (full-term being 31 d) primed with an initial oropharyngeal dose of surfactant. The animals were divided into three groups that received either no supplemental surfactant (n = 20), undried nebulized surfactant (n = 21), or dried nebulized surfactant (n = 24). Drying of the surfactant solution was undertaken to create a hygroscopic aerosol that would facilitate surfactant deposition in the lower respiratory tract. The group treated with dried surfactant aerosol showed superior survival (66.7%) and less evidence of RDS. The control and undried aerosol groups each had similar low survival rates (23.8 and 45.0%, respectively). The results indicate that a dried, hygroscopic aerosol is an effective means of administration of surfactant to spontaneously breathing premature rabbit neonates.