Department of Mechanical and Electrical Engineering, Xiamen University, No. 4221-134, Xiangan South Road, Xiangan South District, Xiamen City, 361102, Fujian Province, China.
Children's Hospital of Xiamen, Xiamen City, 361006, Fujian Province, China.
Sci Rep. 2022 May 5;12(1):7386. doi: 10.1038/s41598-022-10367-w.
Revealing the structural morphology and inner flow field of the upper airway is important for understanding obstructive sleep apnea-hypopnea syndrome (OSAHS) incidence phenomena and pathological diagnosis in children. However, prior work on this topic has been focused on adults and the findings cannot be directly extrapolated to children because of different inducing factors. Therefore, this paper employs a simulation method to investigate upper airway flow characteristics of childhood OSAHS. It is found that the Reynold number changes highly throughout the whole upper airway, and the laminar assumption is no longer suitable for low Reynold number flow, which is much unlike classic fluid mechanics. Turbulent models of Standard k-ω and Spalart-Allmaras were developed prior to suggestion. The simulation is validated by experiments with an error of approximately 20%. Additionally, carried out in this analysis is the influence of adenoidal hypertrophy with different narrow levels. The cross-sectional area, flow velocity, pressure drop and volume rate will change greatly when the narrow level is above 64% of the upper airway, which can be a quantitative explanation for medical intervention if adenoid hypertrophy blocks 2/3 of the upper airway in the common clinical judgment of otorhinolaryngology. It is expected that this paper can be a meaningful instruction on OSAHS surgery plan making as well as recovery evaluation postoperatively.
揭示上呼吸道的结构形态和内部流场对于理解儿童阻塞性睡眠呼吸暂停低通气综合征（OSAHS）的发病现象和病理诊断非常重要。然而，由于诱发因素不同，该主题的先前工作主要集中在成年人身上，因此无法直接推断出儿童的结果。因此，本文采用模拟方法研究儿童 OSAHS 的上呼吸道流场特性。研究发现，整个上呼吸道的雷诺数变化很大，层流假设不再适用于低雷诺数流动，这与经典流体力学有很大不同。在提出建议之前，开发了标准 k-ω和 Spalart-Allmaras 湍流模型。模拟通过实验进行了验证，误差约为 20%。此外，还分析了不同狭窄程度的腺样体肥大的影响。当狭窄程度超过上呼吸道的 64%时，横截面积、流速、压降和体积率会发生很大变化，如果腺样体肥大在耳鼻喉科常见的临床判断中阻塞了上呼吸道的 2/3，这可以作为医学干预的定量解释。本文有望对上气道正压通气治疗阻塞性睡眠呼吸暂停低通气综合征的手术方案制定和术后恢复评估提供有意义的指导。
