Ikarashi Fumio, Tsuchiya Akio
Department of Otolaryngology, Nippon Dental University, School of Life Dentistry at Niigata, Niigata, Japan.
Acta Otolaryngol. 2008 Jan;128(1):9-12. doi: 10.1080/00016480701200269.
It is thought that gas exchange via the mucosa occurred in relation to the partial pressure gradient, and it was impaired mainly by inflammatory changes in the mastoid mucosa. It was verified that gas exchange via the mucosa is less likely to be impaired than gas exchange via the eustachian tube.
To evaluate the capacity of middle ear gas exchange via the mucosa by examining the effect of hyperventilation on middle ear pressure.
A total of 55 patients, 40 patients with a type A tympanogram and 15 with type C, were selected. Tympanometry was performed in one ear every 2 min while hyperventilation was forcibly continued for 44-6 min in the supine position. The middle ear pressure and the pressure of end-tidal carbon dioxide (PETCO2) was measured, and sonotubometry was performed.
PETCO2 decreased gradually as hyperventilation continued in all cases. Although middle ear pressure decreased by hyperventilation in 49 of 55 patients, in 6 patients it hardly decreased despite the decrease in PETCO2. These six patients were treated for otitis media with effusion within 1 month before this examination.
据认为，通过黏膜进行的气体交换与分压梯度有关，其主要因乳突黏膜的炎症变化而受损。经证实，与通过咽鼓管进行的气体交换相比，通过黏膜进行的气体交换不太容易受损。
通过检查过度通气对中耳压力的影响来评估经黏膜的中耳气体交换能力。
共选取55例患者，其中40例鼓室图为A型，15例为C型。在仰卧位强制持续过度通气4～6分钟的同时，每2分钟对一只耳朵进行一次鼓室导抗测试。测量中耳压力和呼气末二氧化碳分压（PETCO2），并进行声导抗咽鼓管测量。
在所有病例中，随着过度通气的持续，PETCO2逐渐降低。尽管55例患者中有49例因过度通气导致中耳压力降低，但有6例患者尽管PETCO2降低，中耳压力却几乎没有下降。这6例患者在本次检查前1个月内曾接受过中耳积液的治疗。
