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 less than .001). A significant statistical difference in Eustachian tube opening pressure was also found between consecutive trials before washing the Eustachian tube with saline (P less than .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.