ABSTRACT
Lung surfactant dysfunction occurs when surface activity is compromised, a phenomenon also called lung surfactant inactivation or inhibition. One important cause of lung surfactant inactivation is direct interactions with endogenous inhibitors that act biophysically to reduce the adsorption and dynamic film activity of alveolar surfactant. The term lung surfactant dysfunction is also used in a broader sense to encompass losses of surface activity following a number of other detrimental processes. These include, for example, chemical degradation of functional surfactant components by lytic enzymes or reactive oxidants present in the lungs during inflammation. Physicochemical or metabolic alterations in lung injury that compromise or selectively deplete the most active large surfactant aggregates can also lead to decreased surface activity. This chapter summarizes characteristic surface activity changes found in lung surfactant dysfunction and gives examples of relevant inhibitors and the mechanisms by which they act. The consequences of decreased surface activity for the physiological effects of lung surfactants on P-V mechanics are also illustrated.
