Fücsek Mihály
Petz Aladár Megyei Oktató Kórház, Csecsemo- és Gyermekgyógyászati Központ Gyermek Fül-orr-gége Részleg Gyor.
Orv Hetil. 2007 Jun 3;148(22):1033-5. doi: 10.1556/OH.2007.27923.
According to our present knowledge, mainly due to O2 absorption the pressure continuously decreases in the normal middle ear, which is equalized by time to time opening of the Eustachian tube, so that air flows across the tube.
The aim of the author is to revise this classic theory on the basis of his own research and the results of the last decades. The basic question is whether the pressure increases or decreases in the normal middle ear between two swallowings?
Middle ear pressure change was examined in 32 ears of 16 healthy children in the swallowing pause (between two swallowings) with tympanometry. The patients were 14 +/- 5.2 years old.
According to the results of the examinations, the middle ear pressure increases between two swallowings in healthy individuals, which is statistically significant (p = 0.028).
In his opinion this can only be explained by one factor, and that is CO2 diffusion. The pressure gradient of CO2 that is directed towards the middle ear cavity is upheld by the Eustachian tube - every time the tube opens the middle ear loses CO2 (the partial pressure of CO2 in the middle ear is higher, in the atmospheric air is very low), so after tube is closed, CO2 diffuses from surrounding tissue to the middle ear and the pressure increases. This CO2 loss can take place if we consider that gases not only flow according to their composition percent, but also diffuse according to their partial pressure difference through the tube.
根据我们目前的知识，在正常中耳中，主要由于氧气吸收，压力持续下降，而咽鼓管会不时打开以平衡压力，从而使空气通过该管道流动。
作者旨在根据自己的研究以及过去几十年的研究结果对这一经典理论进行修正。基本问题是在两次吞咽之间正常中耳内的压力是升高还是降低？
对16名健康儿童的32只耳朵在吞咽间隙（两次吞咽之间）进行鼓室图检查，以检测中耳压力变化。患者年龄为14±5.2岁。
根据检查结果，健康个体在两次吞咽之间中耳压力升高，具有统计学意义（p = 0.028）。
在他看来，这只能由一个因素来解释，即二氧化碳扩散。朝向中耳腔的二氧化碳压力梯度由咽鼓管维持——每次咽鼓管打开时，中耳都会失去二氧化碳（中耳内二氧化碳的分压较高，大气中二氧化碳的分压非常低），所以在咽鼓管关闭后，二氧化碳从周围组织扩散到中耳，压力升高。如果我们认为气体不仅根据其成分百分比流动，还会根据其分压差通过管道扩散，那么这种二氧化碳的损失就会发生。
