LAVAGE ADMINISTRATION OF DILUTE SURFACTANTS AFTER ACUTE LUNG INJURY IN NEONATAL PIGLETS

Exogenous surfactant therapy is not standard in the acute respiratory distress syndrome (ARDS) because of a lack of proven benefit. Nonunifo rm surfactant distribution after either bolus or aerosol administratio n may be an important factor limiting response. In a previous study of acute lung injury, we demonstrated that lavage administration of Exos urf (13.5 mg phospholipid/ml) was both effective and distributed unifo rmly in the lungs. Since the endogenous surfactant pool is much smalle r than the typical dose of exogenous surfactant administered, we hypot hesized that dilute surfactant preparations (44.5 mg phospholipid/ml) administered by lung lavage would be equally effective in reversing pu lmonary dysfunction in a piglet model of acute lung injury. We compare d three dilute surfactants: Infasurf (n = 5), KL4-Surfactant (n = 6), and Exosurf (n = 5) with controls (n = 6) and undiluted Exosurf (13.5 mg phospholipid/ml; n = 6). All dilute surfactant preparations were ef fective in improving oxygenation and other parameters of pulmonary fun ction. Surfactant administered by lavage resulted in uniform lung dist ribution. We conclude that dilute surfactants administered by lung lav age are effective in reversing pulmonary dysfunction after acute lung injury. We speculate that doses in the range of 20-40 mg phospholipid/ kg may be adequate to improve lung function in ARDS when exogenously a dministered surfactant is uniformly distributed in the lung.