Facultad de Enfermería, Universidad de Oviedo. Instituto Nacional de Silicosis and GRUBIPU-ISPA, Asturias, Spain.
Departamento de Energía, Universidad de Oviedo and GRUBIPU-ISPA, Asturias, Spain.
Int J Numer Method Biomed Eng. 2020 Jun;36(6):e3339. doi: 10.1002/cnm.3339. Epub 2020 Apr 13.
Experimental analyses of the flow of drug particles inside the human lung usually require that the patient be exposed to radiation and also of expensive equipment that often lack of enough accuracy. Numerical calculations based on CFD (computational fluid dynamics) have been proven to be a valuable tool to analyze flows in diverse applications.
The complexity of the human lung disallows running calculations on complete lung models due to the large number of cells that would be required. In this work, using a proprietary methodology, particle deposition in the lung is simulated by reducing its multiple branches to a single path.
The tested flow rates were 18, 30, and 75 L min , which are equivalent to different respiratory rates varying from light activity to heavy exercise. Most of the particles are accumulated in the upper airways, mainly at the mouth and also at the confluence of the larynx and the trachea (epiglottis), while the remaining particles travel across the lung. The reported procedure allowed simulating the operation of the entire lung by means of a single individual path.
The obtained calculations are in good agreement with the experimental results found in the technical literature, thus showing that the model can provide a realistic description of the lung operation, while avoiding high computational costs. Moreover, the calculations suggest that particle sizes above 15 μm and inspiratory flows higher than 30 L min must be avoided in order to allow drug particles to reach the lower airways.
在人体肺部内药物颗粒流动的实验分析通常需要使患者暴露在辐射下，并且需要使用昂贵的设备，这些设备往往缺乏足够的准确性。基于计算流体动力学 (CFD) 的数值计算已被证明是分析各种应用中流动的有价值的工具。
由于需要的细胞数量众多，人体肺部的复杂性不允许在完整的肺部模型上进行计算。在这项工作中，通过将多个分支简化为单个路径，使用专有的方法模拟肺部中的颗粒沉积。
测试的流速为 18、30 和 75L/min，分别相当于从轻度活动到剧烈运动的不同呼吸速率。大多数颗粒积聚在上呼吸道，主要在口腔，也在喉和气管（会厌）的汇合处，而其余的颗粒则穿过肺部。所报告的程序允许通过单个个体路径模拟整个肺部的操作。
所获得的计算结果与技术文献中发现的实验结果非常吻合，从而表明该模型可以提供对肺部操作的现实描述，同时避免了高计算成本。此外，计算结果表明，为了允许药物颗粒到达下呼吸道，必须避免粒径大于 15μm 和吸气流量高于 30L/min。
