+1 Recommend
1 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Assessing Static Lung Hyperinflation by Whole-Body Plethysmography, Helium Dilution, and Impulse Oscillometry System (IOS) in Patients with COPD

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          Lung hyperinflation is a feature of chronic obstructive pulmonary disease (COPD) and can determine pivotal consequence on symptoms, exercise tolerance and quality of life. Despite the relevance of assessing lung hyperinflation, there is still no single consensus as to what volume should be taken into account. We investigate which spirometric measurement is more reliable in assessing static lung hyperinflation and which is more related with impulse oscillometry system (IOS) measurements in COPD.

          Patients and Methods

          Fifty-five COPD patients were enrolled. TLC, RV and RV:TLC ratio were obtained both with helium and plethysmography techniques. IOS measurements (X5, Fres and R5-R20) were performed. Pearson and Spearman correlation determined the relationships between the functional parameters that evaluate static hyperinflation (RV: TLC, TLC, RV) and IOS measurements.


          As expected, we reported a statistically significant difference between these two techniques in terms of mean percentage values of TLC (7.57 ± 3.26 L; p= 0.02) and RV (15.24 ± 7.51 L; p=0.04), while RV:TLC measured with the two methods was similar (5.21 ± 4.69%; p=0.27). The correlation analysis showed that IOS parameters, such as difference in resistance between 5 Hz and 20 Hz (R(5–20)) and resonant frequency (Fres), were positively correlated with RV:TLC ratio, while reactance at 5 Hz (X(5)) was negatively correlated with it. In particular, we pointed out a weak correlation between RV:TLC (%) (Pleth) and R(5–20) (r=0.3, p=0.04), Fres (r=0.3; p=0.03), while X5 had a mild correlation with RV:TLC (%) (r=−0.5;p<0.0001). Moreover, we noticed a strong relationship between RV:TLC (%)(He) and X5 (r=−0.7; p=0.0001) and a mild correlation between RV:TLC (%) (He) and Fres (r=0.4; p=0.003). Between R5-R20 and RV:TLC, there was a weak correlation (r=0.3; p=0.001). No correlation between TLC, RV (L,%) (both helium and Pleth derived) and IOS parameters (R(5–20), X5, Fres) was found.


          RV:TLC can represent the most reliable parameter in the assessment of hyperinflation, considering the absence of significant difference in its measurement between the two techniques. IOS provides supplementary information in the assessment of static hyperinflation.

          Related collections

          Most cited references 22

          • Record: found
          • Abstract: not found
          • Article: not found

          Standardisation of spirometry.

            • Record: found
            • Abstract: not found
            • Article: not found

            Interpretative strategies for lung function tests.

              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Pathogenesis of hyperinflation in chronic obstructive pulmonary disease

              Chronic obstructive pulmonary disease (COPD) is a preventable and treatable lung disease characterized by airflow limitation that is not fully reversible. In a significant proportion of patients with COPD, reduced lung elastic recoil combined with expiratory flow limitation leads to lung hyperinflation during the course of the disease. Development of hyperinflation during the course of COPD is insidious. Dynamic hyperinflation is highly prevalent in the advanced stages of COPD, and new evidence suggests that it also occurs in many patients with mild disease, independently of the presence of resting hyperinflation. Hyperinflation is clinically relevant for patients with COPD mainly because it contributes to dyspnea, exercise intolerance, skeletal muscle limitations, morbidity, and reduced physical activity levels associated with the disease. Various pharmacological and nonpharmacological interventions have been shown to reduce hyperinflation and delay the onset of ventilatory limitation in patients with COPD. The aim of this review is to address the more recent literature regarding the pathogenesis, assessment, and management of both static and dynamic lung hyperinflation in patients with COPD. We also address the influence of biological sex and obesity and new developments in our understanding of hyperinflation in patients with mild COPD and its evolution during progression of the disease.

                Author and article information

                Int J Chron Obstruct Pulmon Dis
                Int J Chron Obstruct Pulmon Dis
                International Journal of Chronic Obstructive Pulmonary Disease
                21 October 2020
                : 15
                : 2583-2589
                [1 ]Department of Clinical and Molecular Medicine, Sant’Andrea Hospital, Sapienza University of Rome , Rome, Italy
                [2 ]Department of Cardiovascular and Respiratory Sciences, Sant’Andrea Hospital , Rome, Italy
                Author notes
                Correspondence: Michela D’Ascanio Via di Grottarossa 1035/1039, Roma00189, RM, ItalyTel +390633776768 Email
                © 2020 D’Ascanio et al.

                This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (

                Page count
                Figures: 2, Tables: 5, References: 23, Pages: 7
                Funded by: no financial support;
                The authors received no financial support for the research, authorship, and/or publication of this article.
                Original Research

                Respiratory medicine

                ios, hyperinflation, copd


                Comment on this article