Upper airway occlusion induced by diaphragm pacing for primary alveolar hypoventilation: implications for the pathogenesis of obstructive sleep apnea.

Abstract

This report describes a patient with primary alveolar hypoventilation who, after 2 yr of successful treatment with nocturnal oxygen, developed severe hypoxemia and hypercapnia during sleep, morning headaches, and daytime fatigue. Sleep studies demonstrated prolonged periods of hypoventilation and apnea without evidence of upper airway occlusion. Therefore, a phrenic nerve stimulator was implanted to allow pacing of the diaphragm during sleep. However, diaphragm pacing was accompanied by paradoxical movement of the rib cage and upper airway occlusion during sleep, and was unsuccessful in maintaining adequate ventilation. Therefore, the patient underwent a tracheostomy after which diaphragm pa..