Rajaraman Prathish K, Choi Jiwoong, Hoffman Eric A, O'Shaughnessy Patrick T, Choi Sanghun, Delvadia Renishkumar, Babiskin Andrew, Walenga Ross, Lin Ching-Long
Department of Mechanical Engineering, The University of Iowa, Iowa City, IA, USA.
IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA.
J Aerosol Sci. 2020 Aug;146:105581. doi: 10.1016/j.jaerosci.2020.105581. Epub 2020 Apr 28.
This study numerically investigates the effect of hygroscopicity on transport and deposition of particles in severe asthmatic lungs with distinct airway structures. The study human subjects were selected from two imaging-based severe asthmatic clusters with one characterized by non-constricted airways and the other by constricted airways in the lower left lobe (LLL). We compared the deposition fractions of sodium chloride (NaCl) particles with a range of aerodynamic diameters (1-8 μm) in cluster archetypes under conditions with and without hygroscopic growth. The temperature and water vapor distributions in the airways were simulated with an airway wall boundary condition that accounts for variable temperature and water vapor evaporation at the interface between the lumen and the airway surface liquid layer. On average, the deposition fraction increased by about 6% due to hygroscopic particle growth in the cluster subjects with constricted airways, while it increased by only about 0.5% in those with non-constricted airways. The effect of particle growth was most significant for particles with an initial diameter of in the cluster subjects with constricted airways. The effect diminished with increasing particle size, especially for particles with an initial diameter larger than 4 μm. This suggests the necessity to differentiate asthmatic subjects by cluster in engineering the aerosol size for tailored treatment. Specifically, the treatment of severe asthmatic subjects who have constricted airways with inhalation aerosols may need submicron-sized hygroscopic particles to compensate for particle growth, if one targets for delivering to the peripheral region. These results could potentially inform the choice of particle size for inhalational drug delivery in a cluster-specific manner.
本研究通过数值模拟，研究了吸湿性对具有不同气道结构的重症哮喘患者肺部颗粒传输和沉积的影响。研究对象选自两个基于成像的重症哮喘患者群体，其中一个群体的特征是气道无狭窄，另一个群体的左下叶气道狭窄。我们比较了在有和没有吸湿增长的情况下，一系列空气动力学直径（1-8μm）的氯化钠（NaCl）颗粒在群体原型中的沉积分数。利用气道壁边界条件模拟了气道中的温度和水蒸气分布，该条件考虑了管腔与气道表面液层界面处的可变温度和水蒸气蒸发。平均而言，在气道狭窄的群体受试者中，由于吸湿颗粒的增长，沉积分数增加了约6%，而在气道无狭窄的受试者中仅增加了约0.5%。在气道狭窄的群体受试者中，颗粒增长对初始直径为[此处原文缺失具体数值]的颗粒影响最为显著。随着颗粒尺寸的增加，这种影响减弱，尤其是对于初始直径大于4μm的颗粒。这表明在设计用于定制治疗的气溶胶尺寸时，有必要按群体区分哮喘患者。具体而言，如果目标是将药物递送至外周区域，对于气道狭窄的重症哮喘患者，使用吸入气雾剂治疗可能需要亚微米级的吸湿颗粒来补偿颗粒增长。这些结果可能会以群体特异性的方式为吸入药物递送的颗粒尺寸选择提供参考。
