Background: The authors studied changes in the upper airway in morbidly obese women and the relationship to sleep apnea-hypopnea syndrome (OSAS).
Methods: Patients underwent a cardiorespiratory polygraphic study, respiratory function test (spirometry, plethysmography, maximum inspiratory pressures and arterial blood gas analysis), and computed tomographic studies of the upper airway.
Results: 40 morbidly obese women being evaluated for bariatric surgery (mean age 39.6 +/- 9.6 years old, BMI 48.7 +/- 5.6 kg/m2) were studied. 37 women had OSAS, and 14 had severe OSAS. Results on respiratory function tests were normal. BMI and weight had a positive correlation with apnea-hypopnea index (AHI), apnea index (AI), desaturation index (DI), lowest oxygen saturation and CT90. Uvula diameter had a negative correlation with FEV1, FVC, VC IN and a positive correlation with TLC. Retropharynx soft tissue at the retropalatal level had a negative correlation with FEV1, FVC and VC IN. The oropharynx area at maximal inspiration (total lung capacity) obtained a negative correlation with the AHI (r = - 0.423, P = 0.044), AI (r = - 0.484, P = 0.042) and DI (r = - 0.484, P = 0.019).
Conclusions: Prevalence of OSAS in morbidly obese women is very high. Our results show the significant correlation between BMI and AHI in morbidly obese women. Uvula diameter and retropharynx soft tissue are the upper airway parameters with higher relationship with pulmonary function. A reduction in the cross-sectional area of the airway at the level of the oropharynx could be related to the severity of OSAS in morbidly obese women.