PASSIVE CONSTRICTION OF THE UPPER AIRWAY DURING CENTRAL APNEAS - FIBEROPTIC AND EMG INVESTIGATIONS

We studied five adult male patients with central sleep apnea syndrome (> 75% of the monitored events being central) during sleep using a fib eroptic scope and EMG monitoring of the superior and middle constricto rs of the pharynx and the genioglossus and geniohyoid muscles. The fib eroptic investigation revealed a spontaneous decrease in the size of t he airway during central apneas, without negative intrathoracic pressu re or activation of the superior and middle pharyngeal constrictor mus cles. We found a mean maximum decrease of 71 +/- 7% in the cross-secti onal area of the airway and an absence of superior-middle pharyngeal c onstrictor EMG discharge. We did not observe any complete collapses of the airway. (C) 1997 Elsevier Science B.V.