title: Hyperinflation and expiratory muscle recruitment during NREM sleep in humans.
abstract: 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.
authors: William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705.
authors: R L
authors: RL
authors: Begle
authors: J B
authors: JB
authors: Skatrud
mesh_terms: 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*