Computational fluid dynamics modeling of the upper airway of children with obstructive sleep apnea syndrome in steady flow
Computational fluid dynamics modeling of the upper airway of children with obstructive sleep apnea syndrome in steady flow
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DOI：
10.1016/j.jbiomech.2005.06.021
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发表时间：
2006-01-01
影响因子：
2.4
通讯作者：
Wootton, David M.
中科院分区：
文献类型：
--
作者：
Xu, Chun;Sin, SangHun;Wootton, David M.
采用计算流体动力学（CFD）分析方法，对3例阻塞性睡眠呼吸暂停综合征（OSAS）患儿和3例对照患儿气道几何形状对上气道内压的影响进行了建模。模型几何结构由静息潮汐呼吸时获得的磁共振图像重建，用非结构化网格进行网格划分，并在标准峰值静息流量下求解。采用双方程低雷诺数湍流模型，对非定常雷诺数平均Navier-Stokes方程在吸气和呼气边界条件下进行求解。模型结果通过体外比例模型、非定常流动模拟和报告的儿童鼻阻力测量来验证。咽部压降与气道面积限制密切相关。吸气压降主要与流量的平方成正比，与面积限制导致的对流加速造成的压力损失一致。吸气时，OSAS患者的压降主要发生在由于气道狭窄导致的子宫颈和腺样体与扁桃体重叠的区域（重叠区域）之间，而不是在鼻道；在对照组中，压降主要发生在鼻道。呼气时，OSAS患者的压降主要发生在口咽部（舌后）与重叠区之间，重叠区局部最小压力接近大气压，这是由于鼻咽部前部压力恢复所致。结果表明，与鼻阻力相比，OSAS患儿咽气道形状显著影响内压分布。该模型也可能有助于解释呼气时局部动态气道狭窄。(c) 2005 Elsevier Ltd版权所有。
Computational fluid dynamic (CFD) analysis Was used to model the effect of airway geometry on internal pressure in the upper airway of three children with obstructive sleep apnea syndrome (OSAS), and three controls. Model geometry was reconstructed from magnetic resonance images obtained during quiet tidal breathing, meshed with an unstructured grid, and solved at normative peak resting flow. The unsteady Reynolds-averaged Navier-Stokes equations were solved with steady flow boundary conditions in inspiration and expiration, using a two-equation low-Reynolds number turbulence model. Model results were validated using an invitro scale model, unsteady flow simulation, and reported nasal resistance measurements in children.Pharynx pressure drop strongly correlated to airway area restriction. Inspiratory pressure drop was primarily proportional to the square of flow, consistent with pressure losses due to convective acceleration caused by area restriction. On inspiration, in OSAS pressure drop occurred primarily between the choanae and the region where the adenoids overlap the tonsils (overlap region) due to airway narrowing, rather than in the nasal passages; in controls the majority of pressure drop was in the nasal passages. On expiration, in OSAS the majority of pressure drop occurred between the oropharynx (posterior to the tongue) and overlap region, and local minimum pressure in the overlap region was near atmospheric due to pressure recovery in the anterior nasopharynx. The results suggest that pharyngeal airway shape in children with OSAS significantly affects internal pressure distribution compared to nasal resistance. The model may also help explain regional dynamic airway narrowing during expiration. (c) 2005 Elsevier Ltd. All rights reserved.