Henke K G, Dempsey J A, Badr M S, Kowitz J M, Skatrud J B
John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison 53705.
J Appl Physiol (1985). 1991 Jan;70(1):158-68. doi: 10.1152/jappl.1991.70.1.158.
To investigate the response of inspiratory and expiratory muscles to naturally occurring inspiratory resistive loads in the absence of conscious control, five male "snorers" were studied during non-rapid-eye-movement (NREM) sleep with and without continuous positive airway pressure (CPAP). Diaphragm (EMGdi) and scalene (EMGsc) electromyographic activity were monitored with surface electrodes and abdominal EMG activity (EMGab) with wire electrodes. Subjects were studied in the following conditions: 1) awake, 2) stage 2 sleep, 3) stage 3/4 sleep, 4) CPAP during stage 3/4 sleep, 5) CPAP plus end-tidal CO2 pressure (PETCO2) isocapnic to stage 2 sleep, and 6) CPAP plus PETCO2 isocapnic to stage 3/4 sleep. Inspired pulmonary resistance (RL) at peak flow rate and PETCO2 increased in all stages of sleep. Activity of EMGdi, EMGsc, and EMGab increased significantly in stage 3/4 sleep. CPAP reduced RL at peak flow, increased tidal volume and expired ventilation, and reduced PETCO2. EMGdi and EMGsc were reduced, and EMGab was silenced. During CPAP, with CO2 added to make PETCO2 isocapnic to stage 3/4 sleep, EMGsc and EMGab increased, but EMGdi was augmented in only one-half of the trials. EMG activity in this condition, however, was only 75% (EMGsc) and 43% (EMGab) of the activity observed during eupneic breathing in stage 3/4 sleep when PETCO2 was equal but RL was much higher. We conclude that during NREM sleep 1) inspiratory and expiratory muscles respond to internal inspiratory resistive loads and the associated dynamic airway narrowing and turbulent flow developed throughout inspiration, 2) some of the augmentation of respiratory muscle activity is also due to the hypercapnia that accompanies loading, and 3) the abdominal muscles are the most sensitive to load and CO2 and the diaphragm is the least sensitive.
为了研究在无意识控制的情况下吸气肌和呼气肌对自然发生的吸气阻力负荷的反应，我们对5名男性“打鼾者”在非快速眼动（NREM）睡眠期间进行了研究，睡眠过程中使用和不使用持续气道正压通气（CPAP）。使用表面电极监测膈肌（EMGdi）和斜角肌（EMGsc）的肌电活动，使用线电极监测腹部肌电活动（EMGab）。对受试者在以下条件下进行研究：1）清醒状态，2）2期睡眠，3）3/4期睡眠，4）3/4期睡眠时使用CPAP，5）CPAP加呼气末二氧化碳分压（PETCO2）使其与2期睡眠等碳酸血症，6）CPAP加PETCO2使其与3/4期睡眠等碳酸血症。在所有睡眠阶段，峰值流速时的吸气肺阻力（RL）和PETCO2均升高。在3/4期睡眠时，EMGdi、EMGsc和EMGab的活动显著增加。CPAP降低了峰值流速时的RL，增加了潮气量和呼出通气量，并降低了PETCO2。EMGdi和EMGsc降低，EMGab沉默。在CPAP期间，添加二氧化碳使PETCO2与3/4期睡眠等碳酸血症时，EMGsc和EMGab增加，但仅在一半的试验中EMGdi增强。然而，在此条件下的肌电活动仅为3/4期睡眠时呼吸平稳时观察到的活动的75%（EMGsc）和43%（EMGab），此时PETCO2相等但RL高得多。我们得出结论，在NREM睡眠期间：1）吸气肌和呼气肌对内部吸气阻力负荷以及整个吸气过程中出现的相关动态气道狭窄和湍流作出反应；2）呼吸肌活动的一些增强也归因于负荷伴随的高碳酸血症；3）腹部肌肉对负荷和二氧化碳最敏感，而膈肌最不敏感。
