Causes of airway obstruction during cuffed oropharyngeal airway use.

This study investigated the cause for needing airway maneuvers to maintain a patent airway during the use of cuffed oropharyngeal airway (COPA). Twenty adult patients (29.4+/-6.8 years-old, ASA 1-2) scheduled for minor gynecological surgery who required brief manipulations of the airway despite COPA use following the manufacture's guidelines, were enrolled in this study. To obtain airway patency, 15 patients required only the head-tilt maneuver. In eight of the 15 patients, the laryngeal inlet was opened partially (n=4) or completely (n=4). Despite lifting the epiglottis, the laryngeal inlet was incomplete at the level of pharyngeal view. The patency of the laryngeal inlet was decided by the extent of the distance between the posterior pharyngeal wall and the lateral glossoepiglottic fold, which was made by hyoid bone. In the other seven patients, the head-tilt maneuver elevated the epiglottis and completely opened the laryngeal inlet. Five patients required both the jaw-thrust and head-tilt maneuver. Of these patients lifting the epiglottis was incomplete in three and the laryngeal inlet was partially collapsed in one even after the airway manipulations. The airways in these three patients, however, became patent after manipulations despite the persisting partial obstruction.