Effects of awake tidal breathing, swallowing, nasal breathing, oral breathing and the Müller and Valsalva maneuvers on the dimensions of the upper airway. Evaluation by ultrafast computerized tomography.

Determinations of the size and dynamics of the upper airway during respiration are important in individuals with sleep-related breathing disorders. Ultrafast computerized tomography can acquire eight 8-mm axial-slice thicknesses of the upper airway in 224 ms. If this sequence is acquired every 0.7 second over an entire respiratory cycle and played back in movie mode, the dynamic changes in the airway's size can be evaluated and measured. This report defines the size of the upper airway during normal tidal breathing and describes the changes that occur with swallowing, isolated nasal breathing, and isolated oral breathing and with the Müller and Valsalva maneuvers.