Pneumologie 2024; 78(S 01): S72
DOI: 10.1055/s-0044-1778891
Abstracts
COPD, Bronchiektasie, Cystische Fibrose

Rheologic sputum characteristics in stable vs. exacerbated chronic obstructive pulmonary disease

A Hoheisel
1   Universitätsklinikum Freiburg; Klinik für Pneumologie, Department Innere Medizin, Medizinische Fakultät, Albert Ludwigs Universität, Freiburg, Deutschland; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
A Abdi
2   University Hospital Basel; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
D Schumann
2   University Hospital Basel; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
L Franchetti
2   University Hospital Basel; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
W Chen
2   University Hospital Basel; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
M Tamm
2   University Hospital Basel; Clinic of Respiratory Medicine and Pulmonary Cell Research
,
D Stolz
1   Universitätsklinikum Freiburg; Klinik für Pneumologie, Department Innere Medizin, Medizinische Fakultät, Albert Ludwigs Universität, Freiburg, Deutschland; Clinic of Respiratory Medicine and Pulmonary Cell Research
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    Background One of the characteristic features of an acute exacerbation of COPD (AECOPD) is an increase of volume and purulent transformation of sputum, a mucus solution containing biological material. Rheology assesses the deformation and flow of matter. We examined sputum rheology during stable state and AECOPD.

    Methods Sputum samples were collected in spontaneous mode from patients with COPD during stable state, at the start of AECOPD, and 21 days post exacerbation (AECOPD-fu). The following dynamic rheology parameters using a cone-and-plate rheometer (RheomucoTM, Rheonova, France) were analyzed: elastic modulus G’, viscous modulus G’’, vector sum of viscosity, elasticity G*, damping ratio tanδ, yield strain γc, and yield stress τc.

    Results Samples of 106 patients (mean age at baseline 68±0.8 y, 70% males), collected at visits during stable state (n=156), AECOPD (n=48), and AECOPD-fu (n=30) were examined. No significant differences in G’ (p=0.368), G’’ (p=0.305), G* (p=0.710), tanδ (p=0.117) or τc (p=0.877) were found, however, significant differences in γc (p=0.022) between stable state (median=28.0), AECOPD (median=26.6), and AECOPD-fu (median=30.6) were detected. There was a negative association between pre-bronchodilator FEV1 (L) and FEV1%predicted, BMI and G’ and τc during stable state. No association of FVC and 6MWT with any of the rheological parameters could be detected. A positivity for bacteria in sputum, analyzed with conventional microbiological methods, was found in 66/161 (41%) cases. During AECOPD a difference in yc between positive and negative cases (p=0.006) was observed.

    Conclusions In patients with stable COPD the non-linear property yield strain γc decreases when compared to the state of AECOPD and is found increased again at AECOPD-fu. There is a negative association between sputum rheology and FEV1 and BMI during stable COPD but not during AECOPD.


     

    Publication History

    Article published online:
    01 March 2024

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