Central fatigue of the rabbit diaphragm.
Central fatigue of the rabbit diaphragm.
复制标题
兔子膈肌的中枢疲劳。
作者：
Aldrich,TK
本研究评价了家兔在吸气肌阻力负荷（IRL）下膈肌中枢疲劳的重要性。10只家兔在未麻醉和呼吸补充氧气的情况下接受恒定IRL。在10-20分钟的自主呼吸对IRL，有没有显着的变化，动脉血氧饱和度或膈肌收缩力，测量准静态transmatic压力反应的0.3秒的列车100 Hz的超大膈神经刺激。在由于施加负荷而初始降低后，每分钟通气量进一步降低，平均降低15%，而动脉pCO 2增加至平均59 mmHg（p< 0.05）。在IRL期间，标准化膈肌压力-时间指数最初从0.02增加到0.18，然后平均下降29%（p< 0.05）。这些结果表明，尽管化学驱动增加，尽管肌肉对膈神经刺激的反应能力保留，但随着时间的推移，严重IRL导致肌肉努力水平下降。这种适应可能有助于防止外周隔膜疲劳。
This study evaluates the importance of central fatigue of the diaphragm in rabbits subjected to inspiratory muscle resistive loading (IRL). Ten rabbits were subjected to constant IRL while unanesthetized and breathing supplemental oxygen. During 10–20 minutes of spontaneous breathing against IRL, there were no significant changes in arterial oxygen saturation or in diaphragm contractility, measured by the quasi-static transdiaphragmatic pressure response to a 0.3-sec train of 100 Hz supramaximal phrenic nerve stimuli. After an initial decrease due to application of the load, the minute ventilation decreased further, by an average of 15%, while arterial pCO2increased to an average of 59 mmHg (p< 0.05). The normalized diaphragm pressure-time index initially increased from 0.02 to 0.18 during IRL, then decreased an average of 29% (p< 0.05).These results show that severe IRL causes a decrease in the level of diaphragmatic effort over time despite increased chemical drive and despite a preserved ability of the muscle to respond to phrenic nerve stimuli. This adaptation may help to prevent peripheral diaphragm fatigue.