Lavage administration of dilute recombinant surfactant in acute lung injury in piglets.
In an acute lung injury model, we previously observed reversal of pulmonary dysfunction with natural surfactant administered by lavage (dose = 18 mg/kg phospholipid). The present study questioned whether a lower dose of phospholipid would be effective if a recombinant preparation rather than natural surfactant were used. Acute lung injury was induced by repeated saline lung lavage in ventilated, sedated, and paralyzed piglets. Three concentrations of recombinant surfactant were studied (low phospholipid, 1 mg/mL; medium phospholipid, 4 mg/mL; high phospholipid, 13.5 mg/mL). Control piglets received no surfactant. Thirty-five milliliters per kilogram of surfactant was administered by gravity, followed by passive drainage of excess fluid. All treatment groups retained similar volumes (4.7+/-0.3 mL/ kg), corresponding to phospholipid doses of 4+/-0.4, 22+/-3, and 67+/-4 mg/kg in low, medium, and high-dose groups, respectively. Treatment groups showed significant improvement in Pao2 compared with controls. Other parameters different from controls were found in only the medium and high-dose groups. All surfactant-treated groups showed improvement over time in Pao2, Paco2, lung resistance mean airway pressure, functional residual capacity, and dynamic compliance. These data support the statement that whereas there is a dose response to exogenous surfactant, the effective dose of recombinant surfactant in acute lung injury may be as low as 4 mg/kg phospholipid when administered by lavage.