Surface tension lowering substance in Eustachian tube function.

Abstract

AbstractDirect evidence is presented that establishes the existence of an Eusta‐chian tube surface tension lowering substance (S.T.L.S.) in the canine experimental model. The physiological role of this Eustachian tube S.T.L.S. is to facilitate middle ear ventilation by lowering the opening pressure needed to aerate the Eustachian tube and middle ear. While S.T.L.S. possesses characteristics similar to those of the pulmonary surfactant, experimental data suggest that it does not reduce the surface tension in the auditory conduit of the middle ear to the degree that the surfactant does in pulmonary system. Neither does Eustachian S.T.L.S. exhibit the physical characteristic of “hysteresis” that the alveolar surfactant demonstrates.The paper presents brief discussion of the physical phenomenon of surface tension as it exists in the Eustachian tube. Various methods of physical surface chemistry used in measuring the surface pressure of the canine Eustachian S.T.L.S. extract are discussed, including criticism of the indirect methodology of previous researchers in investigating the possibility of an Eustachian tube S.T.L.S. Direct methodology, utilizing the Langmuir Trough with Wilhelmy surface balance, was employed.S.T.L.S. is considered in its physiologic role in maintaining Eustachian tube patency. It is suggested that a decreased amount of Eustachian S.T.L.S. may be implicated in the pathophysiology of the serous acellular sterile middle ear transudate in serous otitis media. Finally, it is stressed that this preliminary work needs further histochemical and physiological investigation.