EVALUATION OF EXOGENOUS SURFACTANT TREATMENT STRATEGIES IN AN ADULT MODEL OF ACUTE LUNG INJURY

Two exogenous surfactant preparations [Survanta and bovine lipid extra ct surfactant (BLES)] were evaluated in saline lavage-injured adult sh eep with two different delivery methods (instillation vs. aerosolizati on). Instilled BLES resulted in the greatest improvement in lung funct ion, followed by aerosolized Survanta and then instilled Survanta. Aer osolized BLES was ineffective. Total surfactant recovery and distribut ion patterns were similar for Survanta and BLES for each delivery meth od tested. There were significant differences, however in the proporti on of surfactant recovered in the alveolar wash relative to the lung t issue between the groups at killing. Moreover, the ratio of poorly fun ctioning small surfactant aggregates to superior functioning large agg regates isolated from alveolar wash samples correlated with the physio logical responses. The calculated contribution of secreted endogenous surfactant to the total alveolar phospholipid pool at killing was sign ificantly greater for the aerosolized Survanta group compared with the aerosolized BLES group. This finding suggested that there were differ ences in the interaction of the exogenous surfactants and their alveol ar environments. We conclude that the response to exogenous surfactant in acute lung injury depends not only on the preparation used but als o on how the surfactants are delivered to the injured lung.