title: Numerical simulation for the upper airway flow characteristics of Chinese patients with OSAHS using CFD models.
abstract: OSAHS is a common disease with many factors related to the etiology. Airflow plays an important role in the pathogenesis of OSAHS. Previous research has not yielded a sufficient understanding of the relationship between airflow in upper airway and the pathophysiology of OSAHS. Therefore, a better understanding of the flow inside the upper airway in an OSAHS patient is necessary. In this study, ten Chinese adults with OSAHS were recruited. We used the software MIMICS 13.1 to construct 3-dimensional (3-D) models based on the computer tomography scans of them. The numerical simulations were carried out using the software ANSYS 12.0. We found that during the inhalation phase, the vortices and turbulences were located in both the anterior part of the cavity and nasopharynx. But there is no vortex in the whole nasal cavity during the expiratory phase. The airflow velocity is much higher than that of the normal models. The distributions of pressure and wall shear stress are different in two phases. The maximum velocity, pressure and wall shear stress (WSS) are located in velopharynx. It is notable that a strong negative pressure region is found in pharyngeal airway. The maximum velocity is 19.26 ± 12.4 and 19.46 ± 13.1 m/s; the average pressure drop is 222.71 ± 208.84 and 238.5 ± 218.56 Pa and the maximum average WSS is 0.72 ± 0.58 and 1.01 ± 0.61 Pa in inspiratory and expiratory, respectively. The changes of airflow due to the structure changes play an important role in the occurrence of collapse and obstruction of the upper airway, especially, the abnormal pressure changes in velopharyngeal during both inspiratory and expiratory phases. We can say that the airway narrowing in the pharynx may be one of the most important factors driving airway collapse. In addition, the most collapsible region of the pharyngeal airway of the patient with OSAHS may be the velopharynx and oropharynx. In spite of limitations, our results can provide a basis for the further research. On this basis, more about the secret of the pathogenesis of the OSAHS will be revealed.
authors: Department of Otolaryngology Head and Neck Surgery, Fujian Medical University Union Hospital, Xin Quan Road 19, Gulou District, Fuzhou, 350001, Fujian, People's Republic of China. feie1980@163.com
authors: Jie
authors: J
authors: Tan
authors: Jianmin
authors: J
authors: Huang
authors: Jianguo
authors: J
authors: Yang
authors: Desheng
authors: D
authors: Wang
authors: Jianzhi
authors: J
authors: Liu
authors: Jingbo
authors: J
authors: Liu
authors: Shuchun
authors: S
authors: Lin
authors: Chen
authors: C
authors: Li
authors: Haichun
authors: H
authors: Lai
authors: Hongyu
authors: H
authors: Zhu
authors: Xiaohua
authors: X
authors: Hu
authors: Dongxu
authors: D
authors: Chen
authors: Longxiang
authors: L
authors: Zheng
mesh_terms: D000328:Adult; D044466:Asian People; D003198:Computer Simulation; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008297:Male; D008954:Models, Biological; D009666:Nose / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010614:Pharynx / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012984:Software; D014057:Tomography, X-Ray Computed; D055815:Young Adult
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