Despite substantial development of sophisticated subject-specific computational models of aerosol transport and deposition in human lungs, experimental validation of predictions from these new models is sparse. We collected aerosol retention and exhalation profiles in seven healthy volunteers and six subjects with mild-to-moderate COPD (FEV1 = 50-80%predicted) in the supine posture. Total deposition was measured during continuous breathing of 1 and 2.9 μm-diameter particles (tidal volume of 1 L, flow rate of 0.3 L/s and 0.75 L/s). Bolus inhalations of 1 μm particles were performed to penetration volumes of 200, 500 and 800 mL (flow rate of 0.5 L/s). Aerosol bolus dispersion (H), deposition, and mode shift (MS) were calculated from these data. There was no significant difference in total deposition between healthy subjects and those with COPD. Total deposition increased with increasing particle size and also with increasing flow rate. Similarly, there was no significant difference in aerosol bolus deposition between subject groups. Yet, the rate of increase in dispersion and of decrease in MS with increasing penetration volume was higher in subjects with COPD than in healthy volunteers (H: 0.798 ± 0.205 vs. 0.527 ± 0.122 mL/mL, p=0.01; MS: -0.271±0.129 vs. -0.145 ± 0.076 mL/mL, p=0.05) indicating larger ventilation inhomogeneities (based on H) and increased flow sequencing (based on MS) in the COPD than in the healthy group. In conclusion, in the supine posture, deposition appears to lack sensitivity for assessing the effect of lung morphology and/or ventilation distribution alteration induced by mild-to-moderate lung disease on the fate of inhaled aerosols. However, other parameters such as aerosol bolus dispersion and mode shift may be more sensitive parameters for evaluating models of lungs with moderate disease.

中文翻译：

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仰卧健康受试者和轻至中度慢性阻塞性肺病受试者吸入气溶胶的总体和区域沉积


尽管人类肺部气溶胶输送和沉积的复杂的特定主题计算模型得到了实质性发展，但对这些新模型预测的实验验证却很少。我们收集了 7 名健康志愿者和 6 名轻度至中度 COPD 受试者（FEV1 = 50-80% 预测值）仰卧位的气溶胶滞留和呼气曲线。总沉积量是在直径为 1 和 2.9 μm 的颗粒连续呼吸时测量的（潮气量为 1 L，流速为 0.3 L/s 和 0.75 L/s）。 1 μm 颗粒的推注吸入量为 200、500 和 800 mL（流速为 0.5 L/s）。根据这些数据计算气溶胶团剂分散 (H)、沉积和模式转变 (MS)。健康受试者和慢性阻塞性肺病患者之间的总沉积没有显着差异。总沉积量随着颗粒尺寸的增加以及流速的增加而增加。同样，受试者组之间的气溶胶推注沉积也没有显着差异。然而，随着渗透体积的增加，随着渗透体积的增加，离散度增加率和 MS 减少率在 COPD 受试者中高于健康志愿者（H：0.798 ± 0.205 vs. 0.527 ± 0.122 mL/mL，p=0.01；MS：-0.271 ±0.129 vs. -0.145 ± 0.076 mL/mL，p=0.05）表明，与健康组相比，COPD 患者的通气不均匀性更大（基于 H），并且流量排序（基于 MS）增加。总之，在仰卧位时，沉积物似乎缺乏评估轻至中度肺部疾病引起的肺部形态和/或通气分布改变对吸入气溶胶命运的影响的敏感性。 然而，其他参数（例如气溶胶推注分散和模式转换）可能是评估中度疾病肺部模型的更敏感参数。