Surface-Active Agent in Eustachian Tube Function

Using 15 fresh guinea pig temporal bones, Eustachian tubal function was tested repeatedly before and after saline washing to demonstrate the effect of surface-active agent. Although tubal opening pressures for the 15 ears varied considerably, in each ear tested, a higher pressure was required to open the Eustachian tube after saline washing (P <.001). A significant statistical difference in Eustachian tube opening pressure was also found between consecutive trials before washing the Eustachian tube with saline (P <.001). This phenomenon disappeared after saline washing. It is possible that these phenomena occurred as a result of surface-active agent (surfactant) functioning in the Eustachian tube.