Lung Surfactant Spreading - Effect on Lung Function

In patients with acute respiratory distress syndrome (ARDS) pathologic alterations of the lung surfactant system contribute to lung failure. As a result, life threatening hypoxemia and hypercapnia occur. Instillation of lung surfactant into these lungs is expected to restore lung function primarily by dynamic lowering of pathologically increased surface forces. However, first results of clinical trials, where this therapeutic strategy has been employed, are conflicting and reasons for the disparate results unclear. One possible explanation is that lung surfactant, upon endotracheal instillation, does not spread into compromised alveolar units. As a consequence, lung function will not improve as expected. The aim of this study is to use the well characterized hydrophobic surfactant protein B (SP-B) in order to investigate intrapulmonary spreading properties of a commercially available lung surfactant extract in relation to pulmonary perfusion in both animal and human lungs.