Middle ear pressures and the eustachian tube

Authors: Mulder; Kuijpers

Source: Clinical Otolaryngology & Allied Sciences, Volume 23, Number 2, April 1998 , pp. 189-189(1)

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Abstract:

Objective. To evaluate changes in positive and negative middle ear pressures and eustachian tube function in the rat.

Materials and methods. A permanently introduced canula was used to measure the middle ear pressure in the rat. Positive and negative pressures were induced by an infusor system in alert Wistar rats but also under an anaesthetic.

Results. Positive pressure is diminished step by step to atmospheric or to a slightly positive pressure. Negative pressure is equalized step by step to atmospheric or to a slightly negative pressure. When the negative pressure becomes too low amiddle ear effusion will occur. The mean opening pressures in alert animals are 23.64 cm H₂O and in animals during narcosis 25.50 cm H₂O. The closing pressures are respectively 15.83 and 14.04 cm H₂O. The scatter of opening and closing pressures in animals under an anaesthetic is much smaller than in alert animals (P = 0.003 versusP = 0.032).

Conclusions. (1) Opening and closing pressures in rats under narcosis are not significantly different in comparison to alert animals. (2) The larger scatter of values in alert rats is probably due to muscle activity in the tubopharyngeal area. (3) The reaction of the rat eustachian tube to applied positive and negative pressures are comparable to the human situation.

Keywords: audiometry; otosclerosis; second ear; stapedectomy

Document Type: Abstract

DOI: http://dx.doi.org/10.1046/j.1365-2273.1998.0119l.x

Affiliations: 1: Nijmegen, The Netherlands

Publication date: 1998-04-01