Martin J, Aubier M, Engel L A
Am Rev Respir Dis. 1982 Mar;125(3):352-8. doi: 10.1164/arrd.1982.125.3.352.
We studied respiratory muscle activity during expiration in four normal subjects during inspiratory resistive and elastic loading, with and without positive and expiratory pressure. Net inspiratory muscle activity (Pmus) was measured by relating esophageal pressure to the chest wall relaxation pressure-volume (P-V) curve. Abdominal muscle activity (Pabd) was quantitated by relating gastric pressure to the relaxation P-V curve of the abdomen. The decay rates of Pmus and of transdiaphragmatic pressure (Pdi) were increased during loading, and end-expiratory lung volume decreased. The decay rates of Pmus and Pdi were inversely related to expiratory duration. Inspiratory intercostal/accessory activity during expiration was frequently observed together with Pabd, especially during elastic loading. We conclude that external mechanical loads, acting during inspiration, influence respiratory muscle behavior during expiration. Inspiratory loads diminish expiratory braking by the inspiratory muscles and recruit expiratory muscles. The rate of expiration is enhanced and its duration shortened. Simultaneous persistent action of the inspiratory intercostal and accessory muscles throughout expiration may serve to optimize diaphragmatic length.
我们研究了四名正常受试者在吸气阻力和弹性负荷下，有无呼气末正压时呼气过程中的呼吸肌活动。通过将食管压力与胸壁松弛压力-容积（P-V）曲线相关联来测量净吸气肌活动（Pmus）。通过将胃内压力与腹部松弛P-V曲线相关联来定量腹肌活动（Pabd）。负荷期间Pmus和跨膈压（Pdi）的衰减率增加，呼气末肺容积减小。Pmus和Pdi的衰减率与呼气持续时间呈负相关。呼气期间吸气肋间肌/辅助肌活动常与Pabd同时出现，尤其是在弹性负荷期间。我们得出结论，吸气时的外部机械负荷会影响呼气过程中的呼吸肌行为。吸气负荷会减少吸气肌的呼气制动并募集呼气肌。呼气速率增加，持续时间缩短。整个呼气过程中吸气肋间肌和辅助肌的同时持续作用可能有助于优化膈肌长度。
