Abstract
Pulmonary surfactant lines the inner surface of the lung and functions to lower surface tension within the alveolar space, thus minimizing the work of breathing. Surfactant also serves in a host defense role by enhancing bacterial and viral clearance and killing, as well as downregulating, the host inflammatory response. Alterations of the pulmonary surfactant system contribute to the lung dysfunction associated with acute lung injury and the acute respiratory distress syndrome. As a result, exogenous surfactant has been evaluated as a treatment modality for these patients. Unfortunately, the results of these clinical trials have been inconsistent, although a recent large Phase III study showed that patients with direct lung injuries induced by pneumonia and/or aspiration may specifically benefit from this therapy. Future research directions in the surfactant field include prospective clinical trials specifically focused on targeted patient populations as well as studies evaluating the role of the surfactant system in other inflammatory lung diseases such as bronchial asthma and bacterial pneumonia.