Bronchial diseases are characterised by the weak efficiency of mucus transport through the lower airways, leading in some cases to the muco-obstruction of bronchi. It has been hypothesised that this loss of clearance results from alterations in the mucus rheology, which are reflected in sputum samples collected from patients, making sputum rheology a possible biophysical marker of these diseases and their evolution. However, previous rheological studies have focused on quasi-static viscoelastic (linear storage and loss moduli) properties only, which are not representative of the mucus mobilisation within the respiratory tract. In this paper, we extend this approach further, by analysing both quasi-static and some dynamic (flow point) properties, to assess their usability and relative performance in characterising several chronic bronchial diseases (asthma, chronic obstructive pulmonary disease, and cystic fibrosis) and distinguishing them from healthy subjects. We demonstrate that pathologies influence substantially the linear and flow properties. Linear moduli are weakly condition-specific and even though the corresponding ranges overlap, distinct levels can be identified. This directly relates to the specific mucus structure in each case. In contrast, the flow point is found to strongly increase in muco-obstructive diseases, which may reflect the complete failure of mucociliary clearance causing episodic obstructions. These results suggest that the analysis of quasi-static and dynamic regimes in sputum rheology is in fact useful as these regimes provide complementary markers of chronic bronchial diseases.

支气管疾病的特点是通过下呼吸道的粘液运输效率低下，在某些情况下会导致支气管粘液阻塞。据推测，这种清除的丧失是由粘液流变学的改变引起的，这反映在从患者身上收集的痰样本中，这使得痰流变学成为这些疾病及其演变的可能生物物理标志物。然而，以前的流变学研究仅关注准静态粘弹性（线性存储和损失模量）特性，这不能代表呼吸道内的粘液动员。在本文中，我们通过分析准静态和一些动态（流点）属性进一步扩展了这种方法，评估它们在表征几种慢性支气管疾病（哮喘、慢性阻塞性肺病和囊性纤维化）方面的可用性和相对性能，并将它们与健康受试者区分开来。我们证明病理学显着影响线性和流动特性。线性模量是弱条件特异性的，即使相应的范围重叠，也可以识别不同的水平。这与每种情况下的特定粘液结构直接相关。相比之下，在黏液阻塞性疾病中发现流动点强烈增加，这可能反映了黏液纤毛清除的完全失败导致偶发性梗阻。