Effects of inhalant anesthesia on the middle ear as measured by tympanometry.

This investigation examined the effects of inhalant anesthesia, nitrous oxide and halothane, on middle ear pressure. Moreover, the effect of inhalant anesthesia on the validation procedure for tympanometry was examined. Tympanometry was used to measure middle ear pressure variations. Subjects were examined with tympanometry prior to and after the administration of inhalant anesthesia. Group 1 (N = 86) received halothane and nitrous oxide. Group 2 (N = 52) received halothane only. Group 1 data were gathered in a previous investigation. The investigation was continued with subjects in group 2. Results indicated that middle ear status prior to anesthesia was not significantly different from middle ear status under anesthesia. In addition, middle ear pressure changes due to nitrous oxide were not significantly different from middle ear pressure changes due to halothane alone. Moreover, there was no effect on the tympanometry validation procedure. These findings are consistent with previous studies that indicate nonsignificant changes in middle ear pressure associated with the use of nitrous oxide and halothane.