DeWeese E L, Sullivan T Y, Yu P L
J Appl Physiol Respir Environ Exerc Physiol. 1983 Jun;54(6):1525-31. doi: 10.1152/jappl.1983.54.6.1525.
To characterize the ventilatory response to resistive unloading, we studied the effect of breathing 79.1% helium-20.9% oxygen (He-O2) on ventilation and on mouth pressure measured during the first 100 ms of an occluded inspiration (P100) in normal subjects at rest. The breathing circuit was designed so that external resistive loads during both He-O2 and air breathing were similar. Lung resistance, measured in three subjects with an esophageal balloon technique, was reduced by 23 +/- 8% when breathing He-O2. Minute ventilation, tidal volume, respiratory frequency, end-tidal partial pressure of CO2, inspiratory and expiratory durations, and mean inspiratory flow were not significantly different when air was replaced by He-O2. P100, however, was significantly less during He-O2 breathing. We conclude that internal resistive unloading by He-O2 breathing reduces the neuromuscular output required to maintain constant ventilation. Unlike studies involving inhaled bronchodilators, this technique affords a method by which unloading can be examined independent of changes in airway tone.
为了描述对阻力性负荷减轻的通气反应，我们研究了在静息状态下的正常受试者中，呼吸含79.1%氦气-20.9%氧气（He-O₂）对通气以及对在吸气阻断的最初100毫秒期间测量的口腔压力（P100）的影响。呼吸回路的设计使得在呼吸He-O₂和空气时的外部阻力负荷相似。采用食管气囊技术在三名受试者中测量的肺阻力，在呼吸He-O₂时降低了23±8%。当空气被He-O₂替代时，分钟通气量、潮气量、呼吸频率、呼气末二氧化碳分压、吸气和呼气持续时间以及平均吸气流量均无显著差异。然而，在呼吸He-O₂期间P100显著降低。我们得出结论，通过呼吸He-O₂进行的内部阻力性负荷减轻降低了维持恒定通气所需的神经肌肉输出。与涉及吸入支气管扩张剂的研究不同，该技术提供了一种可以独立于气道张力变化来检查负荷减轻的方法。
