The upper airway and obstructive sleep apnea in morbidly obese women

We are currently carrying out a study on the changes of the upper airway in morbidly obese women and the relationship of the upper airway with the severity of obstructive sleep apnea syndrome (OSAS). This study is similar to the study by Fogel RB et al, which appeared in Sleep 2003;2:150-5.

Patients underwent a cardiorespiratory polygraphic sleep study, respiratory function test (spirometry, plethysmography, arterial blood gas analysis), and computed tomographic studies of the upper airway.

Thirteen morbidly obese women being evaluated for weight-reduction surgery.

OSAS was present in all the patients. We found a positive correlation between the uvula diameter and age (r = 0.63, P = .02) and a negative correlation between the area of the oropharynx at the end of maximal expiration and the number of desaturations greater than 4% per hour (r = -0.58, P = .03). In the subgroup of patients with severe OSAS (7 cases), the area of the oropharynx at maximal inspiration had a negative correlation with the apnea-hypopnea index (r = -0.78, P = .03). The resistances of the airway positively correlated with apnea-hypopnea index (r = 0.89, P = .003), apnea index (r = 0.90, P = .03), and desaturation index (r = 0.91, P = .02). The Pao2 had a negative correlation with apnea-hypopnea index (r = -0.63, P = .02), apnea index (r = -0.65, P = .02), and desaturation index (r = -0.66, P = .02).

Our results confirm that, in morbid obese women, airway resistance is higher in those patients with OSAS. We propose that airway resistance and Pao2 can also constitute a good predictor of apnea severity and that a reduction in the cross-sectional area of the airway at the level of the nasopharynx could be related to the severity of OSAS.