DIAPHRAGMATIC AND GENIOGLOSSAL ELECTROMYOGRAM RESPONSES TO ISOCAPNIC HYPOXIA IN HUMANS

Abstract

In order to define the relationship between central control of upper airway and respiratory muscle function, diaphragmatic electromyogram (EMGdi) and genioglossal EMG (EMGge) responses to isocapnic hypoxia were studied in 6 awake supine volunteers. Both EMG were processed and quantitated as moving time average activity. In all subjects, EMGge showed phasic inspiratory activity synchronous with EMGdi. Increases seen in EMGdi and EMGge were linearly related to the decrease in O2 saturation (r = 0.89 .+-. 0.08 and 0.89 .+-. 0.08, respectively). There also was a linear relationship between the relative responses of both EMG to hypoxia such that a low EMGdi response was associated with a low EMGge response and vice versa (r = 0.92, P < 0.001). The genioglossus muscle behaves like a respiratory muscle and central control of upper airway and respiratory muscles in humans may be intimately related.