Department of Ear, Nose, and Throat, Antalya Education and Training Hospital, Antalya, Turkey
Department of Ear, Nose, and Throat, Ankara Dışkapı Yıldırım Beyazıt Education and Training Hospital, Ankara, Turkey
Turk J Med Sci. 2020 Oct 22;50(6):1580-1584. doi: 10.3906/sag-1911-166.
BACKGROUND/AIM: Ischemia is insufficient blood flow to provide adequate oxygenation. In the present study, we aimed to show whether acute hypoxia has a critical oxygen value that may lead to the deterioration of cochlear function.
Under general anesthesia, prehypoxic signal-to-noise ratios were determined by distortion product otoacoustic emissions (DPOAE). The oxygen saturation (SaO2) values of rats were monitored with an oxygen saturation probe. Rats were injected with an extra dose of anesthetic agent, and SaO2 was reduced. DPOAE values in SaO2 100–90, 90–80, 80–70, and 70–60 posthypoxic values were measured and compared statistically with prehypoxic values.
At 3000 and 4000 Hz, SaO2 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 6000 and 8000 Hz, SaO2 80–70 and 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 10,000 Hz, all of the values measured after the hypoxia were observed to be statistically significantly lower than the values obtained before the hypoxia.
Many studies have been conducted on the effects of hypoxia on the inner ear. It remains unclear how fluctuations in DPOAE levels affect hearing in clinical trials when the SaO2 starts to decrease. Although hypoxia has been implicated in the etiology of sudden hearing loss and tinnitus, the effects of acute hypoxia on the cochlea are still uncertain. Further studies are needed on this subject.
背景/目的：缺血是指血液供应不足，无法提供足够的氧气。在本研究中，我们旨在表明急性缺氧是否存在临界氧值，可能导致耳蜗功能恶化。
在全身麻醉下，通过畸变产物耳声发射（DPOAE）确定预缺氧信号-噪声比。用氧饱和度探头监测大鼠的氧饱和度（SaO2）值。给大鼠注射额外剂量的麻醉剂，降低 SaO2。测量 SaO2 为 100-90、90-80、80-70 和 70-60 后 DPOAE 值，并与预缺氧值进行统计学比较。
在 3000 和 4000 Hz 时，测量到缺氧后 SaO2 为 70-60 的值明显低于缺氧前测量到的值。在 6000 和 8000 Hz 时，测量到缺氧后 SaO2 为 80-70 和 70-60 的值明显低于缺氧前测量到的值。在 10000 Hz 时，测量到缺氧后所有的值均明显低于缺氧前的值。
许多研究已经研究了缺氧对内耳的影响。当 SaO2 开始下降时，DPOAE 水平的波动如何影响临床试验中的听力尚不清楚。尽管缺氧与突发性听力损失和耳鸣的病因有关，但急性缺氧对耳蜗的影响仍不确定。需要进一步研究这个问题。
