The effects of transcutaneous electrical stimulation during wakefulness and sleep in patients with obstructive sleep apnea.

Upper airway (UA) collapse in obstructive sleep apnea (OSA) is considered in part to result from the decrease in UA dilator muscle tone that occurs during sleep. We hypothesized that augmentation of UA muscle function by transcutaneous electrical stimulation (TES) might function to enlarge UA size during wakefulness and/or prevent UA collapse during sleep in patients with OSA. Eight male patients with OSA were studied both awake and asleep, with TES administered to the submental region in two patients and to both the submental and subhyoid regions in six patients. Fast-CT scans obtained at FRC and end-inspiration (VTei) demonstrated increased UA size with tidal breathing, p ⩽ 0.05. The active generation of −10 cm H2O pressure at FRC substantially decreased UA size, p ⩽ 0.001. However, no changes in UA size were detected at either FRC or VTei with TES applied at 50 and 100% of the maximal tolerated intensity. The collapsibility of the UA in response to the generation of −10 cm H2O pressure was also unchang...