High-Efficiency Nose-to-Lung Aerosol Delivery in an Infant: Development of a Validated Computational Fluid Dynamics Method
High-Efficiency Nose-to-Lung Aerosol Delivery in an Infant: Development of a Validated Computational Fluid Dynamics Method
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DOI：
10.1089/jamp.2018.1490
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发表时间：
2019-06-01
影响因子：
3.4
通讯作者：
Longest, Worth
中科院分区：
文献类型：
--
作者：
Bass, Karl;Boc, Susan;Longest, Worth
背景：计算流体动力学 (CFD) 为开发新的高效气雾剂输送策略提供了强大的工具，例如使用正确尺寸的气雾剂对婴儿和儿童进行从鼻到肺 (N2L) 的气雾剂给药。本研究的目的是基于与同时进行的体外实验的比较，建立数值有效的 CFD 求解方法和指南，用于模拟婴儿 N2L 气雾剂给药。材料和方法：使用并发 CFD 模拟和体外实验评估微米级气雾剂的 N2L 给药（质量中值空气动力学直径 [MMAD] = 1.4 μm）。在 6 个月大婴儿的新鼻气道几何形状中评估气溶胶输送和沉积，该婴儿具有流线型鼻插管接口，该接口被构建为 CFD 网格并进行三维打印以形成相同的物理原型。所探索的 CFD 网格是具有近壁 (NW) 棱柱元素的传统四面体方法和具有同样精细的 NW 层的新多面体网格样式。使用高效的低雷诺数 (LRN) k-omega 湍流模型评估模型中湍流的存在，并使用先前建立的 NW 校正来解释各向异性壁法向湍流以及改进的 NW 速度插值和流体动力学粒子阻尼。结果：发现使用新的多面体网格可以通过提供更快速的收敛和需要更少的控制体积来提高数值效率。在鼻腔几何形状中发现了由鼻插管接口的入口射流产生的湍流。然而，由于颗粒尺寸小，湍流分散对沉积的影响很小。使用具有适当 NW 校正的数值高效 LRN k-omega 模型的 CFD 预测与体外沉积数据之间建立了良好的一致性。根据实验和 CFD 预测，通过输送管、鼻插管和婴儿鼻模型的气溶胶传输效率分别为 93.0% 和 91.5%。结论：建立了一种数值有效的 CFD 方法来开发婴儿和儿童经鼻气雾剂给药。空气动力学直径接近1.5μm的小颗粒气溶胶被证实具有较低的惯性沉积损失，并且具有较低的湍流分散沉积，使其成为通过婴儿鼻插管接口进行高效肺部输送的理想选择。
Background: Computational fluid dynamics (CFD) provides a powerful tool for developing new high-efficiency aerosol delivery strategies, such as nose-to-lung (N2L) aerosol administration to infants and children using correctly sized aerosols. The objective of this study was to establish numerically efficient CFD solution methods and guidelines for simulating N2L aerosol administration to an infant based on comparisons with concurrent in vitro experiments. Materials and Methods: N2L administration of a micrometer-sized aerosol (mass median aerodynamic diameter [MMAD] = 1.4 mu m) was evaluated using concurrent CFD simulations and in vitro experiments. Aerosol transport and deposition was assessed in a new nasal airway geometry of a 6-month-old infant with a streamlined nasal cannula interface, which was constructed as a CFD mesh and three-dimensionally printed to form an identical physical prototype. CFD meshes explored were a conventional tetrahedral approach with near-wall (NW) prism elements and a new polyhedral mesh style with an equally refined NW layer. The presence of turbulence in the model was evaluated using a highly efficient low-Reynolds number (LRN) k-omega turbulence model, with previously established NW corrections that accounted for anisotropic wall-normal turbulence as well as improved NW velocity interpolations and hydrodynamic particle damping. Results: Use of the new polyhedral mesh was found to improve numerical efficiency by providing more rapid convergence and requiring fewer control volumes. Turbulent flow was found in the nasal geometry, generated by the inlet jets from the nasal cannula interface. However, due to the small particle size, turbulent dispersion was shown to have little effect on deposition. Good agreement was established between the CFD predictions using the numerically efficient LRN k-omega model with appropriate NW corrections and in vitro deposition data. Aerosol transmission efficiencies through the delivery tube, nasal cannula, and infant nasal model, based on experimental and CFD predictions, were 93.0% and 91.5%, respectively. Conclusions: A numerically efficient CFD approach was established to develop transnasal aerosol administration to infants and children. Small particle aerosols with aerodynamic diameters of similar to 1.5 mu m were confirmed to have low inertial depositional loss, and have low deposition from turbulent dispersion, making them ideal for high-efficiency lung delivery through an infant nasal cannula interface.