• Jie-Feng Huang, Gong-Ping Chen, Bi-Ying Wang, Han-Sheng Xie, Jian-Ming Zhao, Li-Hua Wu, Li-Da Chen, and Qi-Chang Lin.
• Fujian Provincial Sleep-Disordered Breathing Clinic Center, Laboratory of Respiratory Disease of the Fujian Medical University, Department of Respiratory Medicine, First Affiliated Hospital of Fujian Medical University, Taijiang District, Fuzhou, Fujian Province, China.
• Respir Care. 2016 Dec 1; 61 (12): 1651-1658.

BackgroundThe purpose of this observational study was to investigate the relationship between upper-airway configuration assessed by CT imaging during the Müller maneuver state and the severity of obstructive sleep apnea syndrome (OSAS).MethodsA total of 358 snoring subjects who underwent standard polysomnography and upper-airway configuration by using CT imaging were enrolled. According to the apnea-hypopnea index (AHI), subjects were classified into 4 groups: snoring group (simple snoring), AHI < 5; mild OSAS, 5 ≤ AHI < 15; moderate OSAS, 15 ≤ AHI < 30; and severe OSAS, AHI ≥ 30. We also divided the upper airway into 3 parts, named the nasopharynx, oropharynx, and hypopharynx, from the CT scan and evaluated the minimal cross-sectional area (mCSA) and the shape of each airway level and calculated upper-airway length and distance from mandibular plane to hyoid bone (MPH).ResultsMultivariate logistic stepwise regression analysis identified body mass index (BMI), mCSA of nasopharynx, upper-airway length, and MPH as risk factors for the severity of OSAS. When subdivided for BMI and sex, upper-airway length was a risk factor for OSAS in non-obese (BMI < 27 kg/m2) and male subjects, and MPH was a risk factor only in obese (BMI ≥ 27 kg/m2) subjects. Meanwhile, mCSA of nasopharynx was significantly associated with the severity of OSAS independent of BMI.ConclusionsSubjects with severe OSAS have more significant abnormalities of the upper airway. Obesity, mCSA of nasopharynx, upper-airway length, and MPH may contribute to the severity of OSAS. Obesity and sex should be taken into account when evaluating the abnormalities of upper-airway anatomy in snorers and patients with OSAS.Copyright © 2016 by Daedalus Enterprises.

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