Twenty-four healthy individuals (6 female) slept with a nasal mask and ventilator. Sleep (EEG, EOG, EMG), ventilation (pneumotachograph), end-tidal CO2 (PETCO2), and intramuscular genioglossus EMG were monitored. NREM eucapnia was determined during 5 minutes on continuous positive airway pressure (4 cmH2O). Inspiratory pressure support was increased until PETCO2 was ≥2 mm Hg below NREM eucapnia. Supplemental CO2 was added to reproduce normocapnia, without changing ventilator settings. Arousals were induced by auditory tones and genioglossus EMG compared during steady-state hypocapnia and normocapnia.
Eleven participants (4 female) provided data. Prearousal PETCO2 was less (p < .05) during hypocapnia (40.74 ± 2.37) than normocapnia (43.82 ± 2.89), with differences maintained postarousal. After-discharge, defined as an increase in genioglossus activity above prearousal levels, occurred following the return to sleep. For tonic activity, after-discharge lasted four breaths irrespective of CO2 condition. For peak activity, after-discharge lasted one breath during hypocapnia and 6 breaths during normocapnia. However, when peak activity following the return to sleep was compared between CO2 conditions no individual breath differences were observed.
Postarousal genioglossal after-discharge may protect against upper airway collapse during sleep. Steady-state CO2 levels minimally influence postarousal genioglossus after-discharge.
24名健康人(6名女性)用鼻罩和呼吸机睡觉。睡眠(脑电图,EOG,EMG),通气(呼吸速度记录仪),潮气末二氧化碳(PETCO2),并监测肌内膝舌肌肌电图。在持续气道正压(4cmH2O)下,在5分钟内确定NREMeucapnia。增加吸气压力支持,直到PETCO2低于NREMeucapnia≥2mmHg。补充二氧化碳是为了复制正常碳酸血症,无需更改呼吸机设置。在稳态低碳酸血症和正常碳酸血症期间,听觉音调和膝舌肌肌电图会引起声调。
11名参与者(4名女性)提供了数据。低碳酸血症(40.74±2.37)期间的觉醒前PETCO2低于正常碳酸血症(43.82±2.89),分歧保持迟钝。放电后,定义为在超过唤醒前水平的膝舌肌活动增加,在恢复睡眠后发生。对于补品活动,无论CO2状况如何,出院后持续四次呼吸。对于峰值活动,出院后在低碳酸血症期间持续一次呼吸,在正常碳酸血症期间持续6次呼吸。然而,当在CO2条件下比较恢复睡眠后的峰值活动时,未观察到个体呼吸差异。
在睡眠过程中,膝舌后放电可以防止上呼吸道塌陷。稳态CO2水平最低程度地影响出院后的the舌。