Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan.
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga-shi, Fukuoka 816-8580, Japan.
Comput Methods Programs Biomed. 2023 Jun;236:107501. doi: 10.1016/j.cmpb.2023.107501. Epub 2023 Mar 22.
From various perspectives (e.g. inhalation exposure and drug delivery), it is important to provide insights into the behavior of inhaled particles in the human respiratory system. Although most of the experimental and numerical studies have relied on an assumption of steady inhalation, the transient breathing profile is a key factor in particle deposition in the respiratory tract. In this study, particle transportation and deposition were predicted in a realistic human airway model during a breathing cycle and the effects of steady-state and transient flows on the deposition fraction were observed using computational fluid dynamics.
Two transient breathing cycles with different respiratory durations were considered to evaluate the effects of respiration duration on particle transport and deposition characteristics. Two types of steady breathing conditions with corresponding steady-state respiratory volumes were reproduced. The Lagrangian discrete phase model approach was used to investigate particle transportation and deposition under transient breathing conditions. Additionally, the Eulerian approach was used to analyze the transport of nanoparticles in the gas phase. A total of >50,000 monodispersed particles with aerodynamic diameters ranging between 2 nm and 10 μm were selected for comprehensive deposition predictions for particle sizes ranging from the nano- to microscale.
The predicted results were compared with the experimental data. The particle deposition fraction in the nasal cavity and tracheal regions showed differences between the steady and transient simulations. In addition, particle analysis under steady inhalation conditions cannot accurately predict particle transportation and deposition in the lower airway. Furthermore, the breathing cycle had a significant effect on the deposition fraction of the particles and the behavior of the inhaled particles.
Transient simulation mimicking the breathing cycle was observed to be an important factor in accurately predicting the transportation and deposition of particles in the respiratory tract.
从各种角度（例如吸入暴露和药物输送）来看，深入了解吸入颗粒在人体呼吸系统中的行为非常重要。尽管大多数实验和数值研究都依赖于稳定吸入的假设，但瞬态呼吸模式是颗粒在呼吸道中沉积的关键因素。在这项研究中，使用计算流体动力学预测了在一个真实人体气道模型中在呼吸周期期间的颗粒输运和沉积，并且观察了稳态和瞬态流对沉积分数的影响。
考虑了两种具有不同呼吸持续时间的瞬态呼吸循环，以评估呼吸持续时间对颗粒输运和沉积特性的影响。再现了两种具有相应稳态呼吸量的稳态呼吸条件。使用拉格朗日离散相模型方法来研究瞬态呼吸条件下的颗粒输运和沉积。此外，使用欧拉方法来分析纳米颗粒在气相中的输运。总共选择了> 50,000 个具有 2nm 至 10μm 之间的空气动力学直径的单分散颗粒，用于对从纳米到微米尺度的颗粒尺寸进行全面的沉积预测。
将预测结果与实验数据进行了比较。在鼻腔和气管区域的颗粒沉积分数在稳态和瞬态模拟之间显示出差异。此外，在稳态吸入条件下的颗粒分析不能准确预测下呼吸道中的颗粒输运和沉积。此外，呼吸周期对颗粒的沉积分数和吸入颗粒的行为有重大影响。
模拟呼吸周期的瞬态模拟被观察为准确预测呼吸道中颗粒输运和沉积的重要因素。
