Effect of Jaw and Head Position on Airway Resistance in Obstructive Sleep Apnea.

This study evaluated whether changes in jaw and neck position caused substantial airway resistance (Raw) changes in normal controls and obstructive sleep apnea (OSA) subjects. Subject groups included 12 male nocturnal polysomnographically diagnosed OSA patients and 16 healthy male control subjects. Raw was assessed plethysmographically and measured under the following conditions: neutral head posture with 0/3, 1/3, 2/3, or 3/3 of the subjects maximum forward jaw position; normal jaw (0/3 forward) with fully flexed, extended, right or left rotated head position. Both groups showed a similar significant decrease in Raw upon jaw protrusion. OSA patients showed a significantly higher baseline (normal jaw, neutral head posture). Raw and both subject groups also had a clear increase in their airway resistance with flexion and to a lesser extent with neck rotation and extension. These data document that airway resistance can be significantly influenced by head and jaw positioning with protrusion of the jaw reducing Raw and flexing the neck increasing Raw.