Rees G L, Freeland A P
Department of Otolaryngology, Radcliffe Infirmary, Oxford, UK.
Clin Otolaryngol Allied Sci. 1992 Jun;17(3):200-2. doi: 10.1111/j.1365-2273.1992.tb01826.x.
A prospective study was designed to assess the effect of anaesthesia, including nitrous oxide, on tympanometric results of children undergoing myringotomy and possible grommet insertion. 155 patients (310 ears) were examined with a pneumatic otoscope and had tympanograms performed within 1 hour of operation. The patients were then anaesthetized by a combination of intravenous and gaseous anaesthetic. Immediately before myringotomy, a tympanogram was repeated. In 13% of patients predicted to have fluid at admission, there was a change in their tympanogram after induction of anaesthesia, suggesting clearance of fluid. At myringotomy, these ears were dry. We surmise that there was displacement of fluid from the middle ear by nitrous oxide during the early stages of anaesthesia. Thus we feel that, if an otologist confidently expects to find an effusion at myringotomy, the presence of a dry tap should not change his management plan.
一项前瞻性研究旨在评估包括氧化亚氮在内的麻醉对接受鼓膜切开术及可能置入通气管的儿童鼓室图结果的影响。155例患者（310耳）在手术前1小时内接受了气动耳镜检查并进行了鼓室图检查。然后患者接受静脉麻醉和气态麻醉联合麻醉。在鼓膜切开术即将开始前，再次进行鼓室图检查。在预计入院时有积液的患者中，13%在麻醉诱导后鼓室图发生了变化，提示积液已清除。在鼓膜切开术时，这些耳朵是干燥的。我们推测在麻醉早期氧化亚氮使中耳内的液体发生了移位。因此我们认为，如果耳科医生有把握预计在鼓膜切开术时会发现积液，干抽的情况不应改变其治疗计划。
