Hyperinflation and expiratory muscle recruitment during NREM sleep in humans.
The purpose of this study was to determine the effect of hyperinflation on expiratory muscle recruitment during NREM sleep in healthy humans. Hyperinflation was produced by negative pressure in a tank ventilator or application of positive end-expiratory pressure (PEEP). Expiratory and inspiratory electromyograms (EMGexp and EMGinsp) were measured using transcutaneously implanted wire and surface electrodes, respectively. During wakefulness, sustained hyperinflation (3-5 min, +0.72 +/- 0.31 L) in the tank respirator caused augmentation of EMGexp (+77%, P less than 0.05) and EMGinsp (+27%, P less than 0.05) in all subjects. Brief hyperinflation with PEEP (5 breaths, +0.53 +/- 0.32 L) augmented EMGexp in 3 of 6 subjects and EMGinsp in 5 of 5 subjects (+98%, P less than 0.05). During NREM sleep, sustained hyperinflation (+0.54 +/- 0.17 L) in the tank respirator caused no change in EMGexp and a small increase in EMGinsp (+9%, P less than 0.001). Brief hyperinflation with PEEP (0.29 +/- 0.10 L) caused no change in EMGexp or EMGinsp. Sustained hyperinflation with PEEP activated EMGexp only in subjects whose end-tidal CO2 increased. We concluded that moderate hyperinflation does not recruit expiratory muscles during NREM sleep as it does during wakefulness.
Begle
R L
RL
William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705.
Skatrud
J B
JB
D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D011175:Positive-Pressure Respiration; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000502:physiology*; D012890:Sleep / Q000502:physiology*