Treatment of meconium aspiration syndrome with surfactant lavage in an experimental rabbit model

Meconium aspiration syndrome (MAS) is a frequent cause of respiratory distress in term infants. Recent reports suggested that surfactant dysfunction contributes to the pathophysiology of MAS. In the present study, we assessed the effect of three different concentrations of surfactant suspensions in the lavage fluid of a rabbit model of MAS. Young animals were given 5 mL/kg of a 20% slurry of human meconium into the endotracheal tube and were then mechanically ventilated. The animals were divided into four groups receiving lavage fluids with either saline or surfactant suspensions (2.5 mg/mL, 5 mg/mL, and 10 mg/mL). Lavage was performed an hour after meconium instillation with one of the four solutions at 10 mL/kg in three divided doses. After lavage, the total amount of meconium recovered was measured. The 10 mg/mL surfactant lavage group had the best improvement in gas exchange, whereas the saline group had no improvement. The amount of meconium recovered was the best in the 10 mg/mL surfactant group among the four groups studied. On histologic examination, alveolar inflammation was less evident in the surfactant lavage groups than in the saline lavage group. It was concluded that lavage with surfactant solution at a concentration of 10 mg/mL washed out meconium most effectively, and improved gas exchange and lung histology in the rabbit model of MAS more than saline lavage.