鼻咽部加压预防低压舱耳气压性损伤

The prevention of the barotitis media by the nasopharynx portion pressure in the hypobaric chamber

目的在低压舱下降时，了解经面罩对鼻咽部加压大于咽鼓管通气阻力时能否预防耳气压伤。方法16名常发生耳气压伤的飞行员和10名志愿者，咽鼓管通气阻力〈6kPa。低压舱以20m／s的下降率自3500m降到地面高度。受试者发生明显的“压耳”感时，进行面罩增压6kPa平衡耳鼓室压。飞行员模拟飞行条件平衡耳鼓室压时，低压舱中止下降高度；志愿者平衡耳鼓室压时，低压舱中止下降高度，并测面罩增压前后的耳鼓室压进行比较。结果在16名飞行员中，有11名需要借助鼻咽部增压才能平衡鼓室压。在11人中有3人为单耳咽鼓管主动通气不良。面罩充气平衡耳鼓室压的次数为2～3次，平均为2．36±0．48次。面罩充气前后的鼓室压分别是-2．04±0．58kPa和-0．09±0．05kPa，差异有统计学上的显著性意义（t=7．132，P〈0．01）。志愿者感到“压耳”时耳鼓室压在-2．17±0．52kPa，面罩加压后耳鼓室压为-0．08±0．06kPa，差异有统计学上的显著性意义（t=6．836，P〈0．01）。结论当人体的环境压力增加时，经面罩提供大于咽鼓管通气阻力的鼻腔充气可以预防耳气压伤的发生。

Objective This study is to find out whether the volunteers are prevented from suffering from ear barotrauma with an nasal cavity pressure higher than the ventilative resistance of the eustachian tube, when they were exposed to environmental of changing barometric pressures in the hypobaric chamber. Methods Sixteen pilots having ear barotrauma frequently and 10 volunteers whose ventilative resistance of the eustachian tubes were lower than 6 kPa. The pressure of the barometric was pressurized from 3500 m to ground at the descending velocity of 20 m/s, When suffering from eardrum pressured, volunteers were provided 6 kPa nasopharynx portion pressure with mask inflation. When the pressure of the tympanic cavity of pilots was balanced under simulated conditions of flying, the hypobaric chamber continued the progress of falling. On the other hand when the volunteers tympanic cavity pressure was balanced, the progress of falling was stopped and measured the tympanic cavity pressure before and after the process of being pressured with mask inflation. Result Among the 16 pilots there were 11 pilots who balanced the pressure between the tympanic cavity and the hypobaric chamber by the nasopharynx portion pressured. Within the 11 pilots there were 3 whose one ear couldn＇t perform positive ventilation well. The pressure between the tympanic cavity and the hypobaric chamber needed to be balanced with mask inflation 2 or 3 times, the average was 2. 36 ±0. 48 times. The tympanic pressure before and after the mask inflation were -2.04±0.58 kPa and -0.09 ± 0.05 kPa respectively. The difference between them was significant（t = 7. 132,P〈0.01）. The pressure in the tympanic cavity while the volunteers suffered from eardrum pressured and after the mask inflation were -2.17±0.52 kPa and -0.08±0.06 kPa respectively. The difference between them was significant（t= 6. 836, P〈0.01）. Conclusion The nasopharynx portion pressure provided by mask inflation, which was higher than the ventilative resistance of the eustachian tube, could prevent an individual who was exposed to the significant increased ambient pressure from ear barotrauma.