[The effects of pressure level in veil on upper airway in patients with obstructive sleep apnea hypopnea syndrome].

Objective: To observe the effects of pressure level in veil on upper airway in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and normal adults.

Method: We scanned the upper airway from roof of nasopharynx to glottis with SIMENS 16 layer spiral CT scanner. The area and the dimensions of palate, uvula, and the region after lingua and epiglottis were measured by application of image work station. Forty-six patients with OSAHS and 35 normal adults were scanned by CT at 0 kPa water column and 0.784 kPa water column pressures in face mask, respectively.

Result: The area and inner diameter of OSAHS patients upper airways were less than those of normal adults at the same pressure in face mask. The area and inner diameter of upper airway at the pressure of 0.784 kPa water column were more than those at 0 kPa water column in both OSAHS patients and normal adults, and the increased extent of normal adults were more than those of OSAHS patients. We measured the minimum increased normal Cross sectional area of palate, uvula, and the region after lingua and epiglottis when the pressure in the mask increased from 0 kPa to 0.784 kPa, and we made it as the standard. The 46 OSAHS patients were sorted into 17 cases (group 1) with normal dilation and 29 cases (group 2) with less dilation in such standard. There was not significant difference between the two groups at 0 kPa pressures in area and inner diameter, but the area and inner diameter of group 1 were more than those of group 2 at 0.784 kPa pressure.

Conclusion: The increased pressure in face mask would lead to upper airway dilation both in OSAHS patients and normal adults, and the dilated extents of normal adults were significant more than those of OSAHS patients. The less dilation of OSAHS may be duo to anatomic constriction and some pharynx wall pathological changes.