Inspiratory Minute Ventilation Research Articles

The effect of sleep deprivation on activity of the genioglossus muscle.

Sleep deprivation appears to increase the severity of obstructive sleep apnea, and inadequate activation of the genioglossus muscle may play an important role in the pathogenesis of obstructive sleep apnea. Therefore, we investigated the effect of sleep deprivation on genioglossal electromyographic (EMG) activity. Eleven men were studied during room air breathing and CO2 rebreathing before sleep deprivation (control), after 1 night of sleep deprivation, and the day after sleep recovery. We measured inspired minute ventilation, tidal volume, respiratory frequency, and peak integrated inspiratory genioglossal EMG activity. After sleep deprivation, no significant changes in inspiratory minute ventilation or tidal volume occurred during room air breathing or CO2 rebreathing, but the breathing frequency during CO2 rebreathing increased significantly after sleep deprivation. Genioglossal EMG activity was diminished during CO2 rebreathing after sleep deprivation, but this was significant only in subjects 30 yr of age and older. The fall in EMG activity was independent of changes in tidal volume. All variables returned towards control levels after sleep recovery. We conclude that sleep deprivation selectively decreases genioglossal EMG activity during CO2 rebreathing in awake older subjects. This influence of sleep deprivation may play a role in the pathogenesis or severity of obstructive sleep apnea.

Target device for regulating ventilation during voluntary hyperpnea.

A ventilatory target device is described enabling subjects to maintain specified levels of ventilation during voluntary hyperpnea. Inspired air passes through a linear resistor. The associated pressure drop is measured and displayed by a mechanical manometer with a very slow response. This time-mean pressure is proportional to time-mean inspiratory flow and thus to inspired minute ventilation. Construction and calibration are described. Inspiratory resistances range between 0.6 and 1.9 cmH2O X 1(-1)S for devices with capacities up to 240 and 80 l/min, respectively. The device is simple, cheap, stable, portable, rugged, unpowered, and accurate. Inexperienced subjects quickly learn to use it and can maintain ventilations within about 5% of specified values.