Effects of withdrawal of phasic lung inflation during normocapnia and hypercapnia on the swallowing reflex in humans
Effects of withdrawal of phasic lung inflation during normocapnia and hypercapnia on the swallowing reflex in humans
复制标题
正常碳酸血症和高碳酸血症期间取消阶段性肺充气对人类吞咽反射的影响
DOI：
10.1007/s00540-004-0231-y
复制
发表时间：
2004
影响因子：
2.8
通讯作者：
T. Nishino
中科院分区：
文献类型：
--
作者：
T. Sai;S. Isono;T. Nishino
目的本研究旨在验证高碳酸血症对吞咽有直接抑制作用的假设。方法观察12名健康志愿者在低碳酸血症和高碳酸血症时短暂性气道阻塞前、中、后连续咽部输水诱导的重复吞咽次数和时间的变化。通过增加死区诱导高碳酸血症。使用气测仪监测通气，并通过颏下肌电图识别吞咽。结果我们发现高碳酸血症降低了燕子的频率（8.2±3.7 vs 11.4±5.3·min - 1 [mean±SD]：高碳酸血症vs正常碳酸血症；P≪0.05），同时在正常碳酸血症下观察到的燕子与呼气相的优势耦合丧失。我们还发现，呼气末气道阻塞引起的肺相性充气的消失会突然增加吞咽频率，无论是在正常血氧状态下（从11.4±5.3到16.7±3.7吞·min - 1； P≪0.01）还是在高血氧状态下（从8.2±3.7到22.0±6.7吞·min - 1； P≪0.01）。虽然高碳酸血症时气道闭塞时吞咽频率增加的程度比低碳酸血症时更为明显（P≪0.05），但高碳酸血症时气道闭塞时吞咽时间与呼吸周期相关系的分布与低碳酸血症时气道闭塞时相似。结论我们的研究结果强烈提示，高碳酸时吞咽反射的减弱不是由于CO2对吞咽中枢的直接抑制作用，而是由于肺容量相关反射的抑制作用增强。
PurposeThis study was done to test the hypothesis that hypercapnia has a direct, inhibitory effect on swallowing.MethodsWe investigated changes in the frequency and timing of repeated swallows induced by continuous infusion of water into the pharynx before, during, and after transient airway occlusion at normocapnia and hypercapnia in 12 healthy volunteers. Hypercapnia was induced by adding a dead space. Ventilation was monitored using a pneumotachograph, and swallowing was identified by submental electromyogram.ResultsWe found that hypercapnia decreased the frequency of swallows (8.2 ± 3.7 vs 11.4 ± 5.3 swallows·min−1 [mean ± SD]: hypercapnia vs normocapnia; P ≪ 0.05), together with a loss of the preponderant coupling of swallows with expiratory phase observed at normocapnia. We also found that the withdrawal of phasic lung inflation produced by airway occlusion at end-expiration suddenly increased the swallowing frequency, both at normocapnia (from 11.4 ± 5.3 to 16.7 ± 3.7 swallows·min−1; P ≪ 0.01) and at hypercapnia (from 8.2 ± 3.7 to 22.0 ± 6.7 swallows·min−1; P ≪ 0.01). Although the degree of increased swallowing frequency during airway occlusion was more prominent at hypercapnia than at normocapnia (P ≪ 0.05), the distribution of the timing of swallows in relation to the phase of the respiratory cycle during airway occlusion at hypercapnia was similar to that during airway occlusion at normocapnia.ConclusionThe results of our study strongly suggest that the attenuation of the swallowing reflex during hypercapnia is not due to the direct, inhibitory effect of CO2 on the swallowing center, but, rather, is due to the increased inhibitory influence of a lung-volume-related reflex.