Kanbar Center for Biomedical Engineering and Department of Mechanical Engineering, The Cooper Union for the Advancement of Science and Art, New York, New York;
J Appl Physiol (1985). 2014 Jan 1;116(1):104-12. doi: 10.1152/japplphysiol.00746.2013. Epub 2013 Nov 21.
Computational fluid dynamics (CFD) analysis may quantify the severity of anatomical airway restriction in obstructive sleep apnea syndrome (OSAS) better than anatomical measurements alone. However, optimal CFD model endpoints to characterize or assess OSAS have not been determined. To model upper airway fluid dynamics using CFD and investigate the strength of correlation between various CFD endpoints, anatomical endpoints, and OSAS severity, in obese children with OSAS and controls. CFD models derived from magnetic resonance images were solved at subject-specific peak tidal inspiratory flow; pressure at the choanae was set by nasal resistance. Model endpoints included airway wall minimum pressure (Pmin), flow resistance in the pharynx (Rpharynx), and pressure drop from choanae to a minimum cross section where tonsils and adenoids constrict the pharynx (dPTAmax). Significance of endpoints was analyzed using paired comparisons (t-test or Wilcoxon signed rank test) and Spearman correlation. Fifteen subject pairs were analyzed. Rpharynx and dPTAmax were higher in OSAS than control and most significantly correlated to obstructive apnea-hypopnea index (oAHI), r = 0.48 and r = 0.49, respectively (P < 0.01). Airway minimum cross-sectional correlation to oAHI was weaker (r = -0.39); Pmin was not significantly correlated. CFD model endpoints based on pressure drops in the pharynx were more closely associated with the presence and severity of OSAS than pressures including nasal resistance, or anatomical endpoints. This study supports the usefulness of CFD to characterize anatomical restriction of the pharynx and as an additional tool to evaluate subjects with OSAS.
计算流体动力学（CFD）分析可能比仅进行解剖学测量更能量化阻塞性睡眠呼吸暂停综合征（OSAS）中解剖气道限制的严重程度。然而，尚未确定最佳的 CFD 模型终点来描述或评估 OSAS。为了使用 CFD 模拟上气道流体动力学，并研究各种 CFD 终点、解剖学终点与 OSAS 严重程度之间的相关性强度，对患有 OSAS 和对照组的肥胖儿童进行了研究。在特定个体的最大潮气量吸气流量下，对从磁共振成像中得出的 CFD 模型进行了求解；通过鼻腔阻力设定后鼻孔处的压力。模型终点包括气道壁最小压力（Pmin）、咽腔阻力（Rpharynx）以及从后鼻孔到扁桃体和腺样体限制咽腔的最小横截面积处的压力降（dPTAmax）。使用配对比较（t 检验或 Wilcoxon 符号秩检验）和 Spearman 相关分析来分析终点的显著性。分析了 15 对受试者。与对照组相比，OSAS 患者的 Rpharynx 和 dPTAmax 更高，与阻塞性呼吸暂停低通气指数（oAHI）的相关性最显著，分别为 r = 0.48 和 r = 0.49（P < 0.01）。与 oAHI 的相关性较弱（r = -0.39）；Pmin 与 oAHI 无显著相关性。与包括鼻阻力或解剖学终点的压力相比，基于咽腔压降的 CFD 模型终点与 OSAS 的存在和严重程度更为密切相关。本研究支持使用 CFD 来描述咽腔的解剖学限制，并作为评估 OSAS 患者的附加工具的有用性。
