1/2. nitrous oxide and the middle ear.A case of hearing deficit following nitrous oxide anaesthesia is reported. The mechanism and time course of nitrous oxide-induced intratympanic pressure changes are described and contrasted with the effects of non-nitrous oxide anaesthesia. The rate of increase is about 10 mm H20/min. The possibility that nitrous oxide may cause displacement of tympanic membrane grafts both outwards and inwards, or disrupt the reconstructed middle ear conducting mechanism, is raised again.- - - - - - - - - - ranking = 1keywords = anaesthesia (Clic here for more details about this article) |
2/2. Ear injury caused by elevated intratympanic pressure during general anaesthesia.Two cases of middle-ear injury, due to sharp fluctuations of intratympanic pressure as a result of general anaesthesia with nitrous oxide are presented. A study is reported indicating that the degree of these fluctuations is a function of the concentration of nitrous oxide. In order to reduce the risk of middle-ear injury due to nitrous oxide anaesthesia, it is suggested that the lowest concentration feasible should be used where there is a history of previous ear surgery.- - - - - - - - - - ranking = 3keywords = anaesthesia (Clic here for more details about this article) |