Surfactant in the middle ear and eustachian tube: a review.

There has been a recent surge in research on surfactant and surfactant proteins. Fields ranging from immunology to surface chemistry are making contributions to our understanding of this multifunctional compound. This paper reviews the literature on the structure and function of Eustachian tube surfactant. It covers the proposed functions of endogenous surfactant in normal physiology, as well as the experimental applications of exogenous surfactant in the treatment of otitis media. The analysis is based on four platforms of research: the role of surfactant in the innate immune system, the effect of surfactant on surface tension and Eustachian tube opening pressure, the capacity of surfactant to alter the rheological properties of mucus and the efficiency of the mucociliary system, and the ability of surfactant to mitigate oxygen free radical damage.