Skip to main content

Main menu

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • COVID-19 submission information
    • Peer reviewer login
  • Alerts
  • Podcasts
  • Subscriptions
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

User menu

  • Log in
  • Subscribe
  • Contact Us
  • My Cart

Search

  • Advanced search
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

Login

European Respiratory Society

Advanced Search

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • Authors/reviewers
    • Instructions for authors
    • Submit a manuscript
    • Open access
    • COVID-19 submission information
    • Peer reviewer login
  • Alerts
  • Podcasts
  • Subscriptions

Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach

R. Farré, D. Navajas
European Respiratory Journal 2004 23: 187-188; DOI: 10.1183/09031936.04.00131804
R. Farré
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
D. Navajas
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Info & Metrics
  • PDF
Loading

Patients with severe chronic obstructive pulmonary disease (COPD) usually experience expiratory flow limitation (EFL) during spontaneous breathing at rest 1. As EFL reduces the effectiveness of expiration, it results in dynamic hyperinflation with consequent dyspnoea, which is one of the major complaints of patients with COPD. In these patients, the consequences of EFL are markedly increased during exercise 2. Bearing in mind that EFL is a good predictor of dyspnoea in COPD patients 3, 4, simple methods for detecting EFL without perturbing normal breathing are of clinical interest. In 1995 Koulouris et al. 5 proposed a method to detect EFL based on the external application of a negative pressure at the mouth during tidal expiration (negative expiratory pressure (NEP)). EFL is detected by comparing the magnitude of expiratory flow before and after application of NEP: in case of EFL, the expiratory flow does not rise when increasing the driving pressure. More recently, Ninane et al. 6 proposed the estimation of EFL during spontaneous breathing with a similar approach. To increase the driving pressure during expiration, these authors applied a positive abdominal pressure by manual compression of the patient's abdominal wall. When compared with the NEP technique, this approach has the advantage of instrumental simplicity, but suffers from the drawbacks of applying abdominal pressure of uncontrolled magnitude and lack of automatisation. Both procedures can be applied during breathing at rest as well as during exercise 7, 8.

In this issue of the European Respiratory Journal (ERJ), Dellacà et al. 9 present interesting novel data showing that the forced oscillation technique (FOT) can be useful for noninvasively detecting EFL during spontaneous breathing. The FOT, which was proposed in the 1950s 10, is based on applying a small-amplitude oscillation pressure at the mouth. Using the FOT the patient's respiratory mechanics can be determined by simply recording the oscillatory pressure and flow signals at the mouth, provided that the oscillation frequency is much higher than the breathing rate. The relationship between the pressure and the flow oscillation is the impedance of the respiratory system, which has two components: respiratory resistance (Rrs) and reactance (Xrs). In a simple interpretation, Rrs is attributed to airways and tissue resistances, whereas Xrs is determined by the inertial and compliant properties of the respiratory system. The rationale of using FOT for assessing EFL is that under this flow regime the forced oscillation applied at the mouth cannot reach the alveoli given the fact that the choke point shifts upstream of the lung during EFL. Therefore, the effective impedance viewed from the FOT device corresponds to only a fraction of the respiratory system: from the mouth to the choke point. According to this hypothesis, the associated decrease in the effective respiratory compliance results in a reduction of the measured Xrs during expiration when compared with the non flow-limited inspiration.

The notion that phasic changes in Xrs during the breathing cycle could be an index of EFL is not new. This was suggested in 1993 by Peslin et al. 11 when studying mechanically ventilated COPD patients, and the hypothesis was more specifically substantiated in a controlled analog model 12 and animal studies 13. However, the usefulness of the FOT for detecting EFL in spontaneously breathing COPD patients was not studied in detail before the work of Dellacà et al. 9 published in this issue of the ERJ. These authors analysed the sensitivity and specificity of FOT to detect EFL in each individual breathing cycle by computing the phasic changes in Xrs within the cycle. As a reference technique to assess whether EFL was present or not in the same breathing cycle, Dellacà et al. 9 used the Mead and Whittenberger 14 method. This is based on the graphic analysis of the loop determined by the flow signal and by the resistive component of the transpulmonary pressure signal, which is measured by means of an oesophageal balloon.

The results reported by Dellacà et al. 9 strongly support their hypothesis that the FOT applied at a frequency of 5 Hz is a useful tool for detecting EFL in spontaneously breathing COPD patients. Specifically, the authors report that they were able to find thresholds for the indices representing the phasic changes in Xrs that resulted in a 100% sensitivity and specificity. Obviously, these excellent results, which were obtained from a research pilot study including a limited number of patients and controls, need to be further confirmed by more extensive studies. In this regard, a key issue is whether the thresholds found by the authors would keep their high sensitivity and specificity when applied to a wider sample of patients. However, according to the data and reasoning provided by the authors, it is plausible to expect further support for their conclusions when the technique is applied in future studies. Another major issue warranting future studies is to what extend the FOT allows determination of the part expiration under EFL. Moreover, the technique should be assessed during exercise, particularly to determine whether a FOT frequency of 5 Hz is sufficiently high to keep an acceptable signal-to-noise ratio given the expected increase in the patient's breathing rate. The promising results reported by Dellacà et al. 9 as regards the application of the FOT toassess EFL also warrant further studies applying this technique and the NEP method in the same patients to compare the practical advantages and disadvantages of both approaches.

Besides its specific interest as a technique to assess EFL, the work of Dellacà et al. 9 is also relevant to better clarify some issues on the interpretation of Rrs and Xrs values measured by the FOT in routine applications in patients who are potentially under EFL. As has been recently summarised by a European Respiratory Society Task Force report on the FOT 15, the Rrs values measured by this technique are useful to quantify airway obstruction in a variety of applications. However, the data from Dellacà et al. 9 suggest that Xrs could be a more suitable index than Rrs to assess respiratory mechanics during EFL. The results of these authors also indicate 12, 13 that averaging the impedance data over the whole breathing cycle, which is the most common procedure 15, could result in data misinterpretation when FOT is applied in COPD patients. Accordingly, tracking the impedance data along the breathing cycle or, at least, separating inspiratory and expiratory data could improve the performance of FOT in evaluating the respiratory mechanics of COPD patients 9, 12, 13.

It is worth noting that the approach proposed by Dellacà et al. 9 to assess EFL is readily applicable in routine. Indeed, it allows the automatic and continuous assessment of EFL based on FOT indices obtained by the simple application of a relatively low frequency (5 Hz) sinusoidal oscillation during spontaneous breathing. The advantage of such a simple FOT setting is that the proposed procedure can be applied not only in the lung function laboratory but in other situations where assessment of EFL could be of considerable interest. First, given that 5‐Hz sinusoidal oscillation can be easily incorporated into noninvasive mechanical ventilators 16, it could be possible to assess whether a ventilated patient is experiencing EFL and to modify the ventilator settings to improve ventilation. Second, it has been recently reported that a 5‐Hz sinusoidal FOT can be implemented in a portable device 17 allowing the patient to self-assess their impedance at home 18. Accordingly, application of the method proposed by Dellacà et al. 9 in this setting could allow an easy monitoring of EFL in COPD patients at home.

In conclusion, the research work of Dellacà et al. 9 provides solid evidence that the forced oscillation technique is a simple procedure for detecting expiratory flow limitation during normal breathing. Future clinical studies should assess how the forced oscillation technique compares with other automatically applicable methods such as negative expiratory pressure, and should demonstrate the potential effectiveness of routine assessment of expiratory flow limitation in chronic obstructive pulmonary disease patients during spontaneous breathing at rest and during exercise.

    • © ERS Journals Ltd

    References

    1. ↵
      Hyatt RE. The interrelationship of pressure, flow and volume during various respiratory maneuvers in normal and emphysematous patients. Am Rev Respir Dis 1961;83:676–683.
      OpenUrlPubMedWeb of Science
    2. ↵
      Marin JM, Carrizo SJ, Gascon M, Sanchez A, Gallego B, Celli BR. Inspiratory capacity, dynamic hyperinflation, breathlessness, and exercise performance during the 6‐minute-walk test in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2001;163:1395–1399.
      OpenUrlPubMedWeb of Science
    3. ↵
      Eltayara L, Becklake MR, Volta CA, Milic-Emili J. Relationship between chronic dyspnea and expiratory flow limitation in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1996;154:1726–1734.
      OpenUrlPubMedWeb of Science
    4. ↵
      Boni E, Corda L, Franchini D, et al. Volume effect and exertional dyspnoea after bronchodilator in patients with COPD with and without expiratory flow limitation at rest. Thorax 2002;57:528–532.
      OpenUrlAbstract/FREE Full Text
    5. ↵
      Koulouris NG, Valta P, Lavoie A, et al. A simple method to detect expiratory flow limitation during spontaneous breathing. Eur Respir J 1995;8:306–313.
      OpenUrlAbstract
    6. ↵
      Ninane V, Leduc D, Kafi SA, Nasser M, Houa M, Sergysels R. Detection of expiratory flow limitation by manual compression of the abdominal wall. Am J Respir Crit Care Med 2001;163:1326–1330.
      OpenUrlPubMedWeb of Science
    7. ↵
      Koulouris NG, Dimopoulou I, Valta P, Finkelstein R, Cosio MG, Milic-Emili J. Detection of expiratory flow limitation during exercise in COPD patients. J Appl Physiol 1997;82:723–731.
      OpenUrlAbstract/FREE Full Text
    8. ↵
      Abdel Kafi S, Serste T, Leduc D, Sergysels R, Ninane V. Expiratory flow limitation during exercise in COPD: detection by manual compression of the abdominal wall. Eur Respir J 2002;19:919–927.
      OpenUrlAbstract/FREE Full Text
    9. ↵
      Dellacà RL, Santus P, Aliverti A, et al. Detection of expiratory flow limitation in COPD using the forced oscillation technique. Eur Respir J 2004;23:232–240.
      OpenUrlAbstract/FREE Full Text
    10. ↵
      DuBois AB, Brody AW, Lewis DH, Burgess BF. Oscillation mechanics of lungs and chest in man. J Appl Physiol 1956;8:587–594.
      OpenUrlFREE Full Text
    11. ↵
      Peslin R, Felicio da Silva J, Duvivier C, Chabot F. Respiratory mechanics studied by forced oscillations during artificial ventilation. Eur Respir J 1993;6:772–784.
      OpenUrlAbstract/FREE Full Text
    12. ↵
      Peslin R, Farre R, Rotger M, Navajas D. Effect of expiratory flow limitation on respiratory mechanical impedance: a model study. J Appl Physiol 1996;81:2399–2406.
      OpenUrlAbstract/FREE Full Text
    13. ↵
      Vassiliou M, Peslin R, Saunier C, Duvivier C. Expiratory flow limitation during mechanical ventilation detected by the forced oscillation method. Eur Respir J 1996;9:779–786.
      OpenUrlAbstract
    14. ↵
      Mead J, Whittenberger JL. Physical properties of human lungs measured during spontaneous respiration. J Appl Physiol 1953;5:779–796.
      OpenUrlWeb of Science
    15. ↵
      Oostveen E, MacLeod D, Lorino H, et al. The forced oscillation technique in clinical practice: methodology, recommendations and future developments. Eur Respir J 2003;22:1026–1041.
      OpenUrlAbstract/FREE Full Text
    16. ↵
      Farre R, Mancini M, Rotger M, Ferrer M, Roca J, Navajas D. Oscillatory resistance measured during noninvasive proportional assist ventilation. Am J Respir Crit Care Med 2001;164:790–794.
      OpenUrlPubMedWeb of Science
    17. ↵
      Rigau J, Farre R, Roca J, Marco S, Herms A, Navajas D. A portable forced oscillation device for respiratory home monitoring. Eur Respir J 2002;19:146–150.
      OpenUrlAbstract/FREE Full Text
    18. ↵
      Rigau J, Burgos F, Hernandez C, Roca J, Navajas D, Farre R. Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home. Eur Respir J 2003;22:668–671.
      OpenUrlAbstract/FREE Full Text
    View Abstract
    PreviousNext
    Back to top
    View this article with LENS
    Vol 23 Issue 2 Table of Contents
    • Table of Contents
    • Index by author
    Email

    Thank you for your interest in spreading the word on European Respiratory Society .

    NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

    Enter multiple addresses on separate lines or separate them with commas.
    Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach
    (Your Name) has sent you a message from European Respiratory Society
    (Your Name) thought you would like to see the European Respiratory Society web site.
    CAPTCHA
    This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
    Print
    Citation Tools
    Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach
    R. Farré, D. Navajas
    European Respiratory Journal Feb 2004, 23 (2) 187-188; DOI: 10.1183/09031936.04.00131804

    Citation Manager Formats

    • BibTeX
    • Bookends
    • EasyBib
    • EndNote (tagged)
    • EndNote 8 (xml)
    • Medlars
    • Mendeley
    • Papers
    • RefWorks Tagged
    • Ref Manager
    • RIS
    • Zotero

    Share
    Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach
    R. Farré, D. Navajas
    European Respiratory Journal Feb 2004, 23 (2) 187-188; DOI: 10.1183/09031936.04.00131804
    del.icio.us logo Digg logo Reddit logo Technorati logo Twitter logo CiteULike logo Connotea logo Facebook logo Google logo Mendeley logo
    Full Text (PDF)

    Jump To

    • Article
      • References
    • Info & Metrics
    • PDF
    • Tweet Widget
    • Facebook Like
    • Google Plus One

    More in this TOC Section

    • Interstitial abnormalities on CT associated with hiatus hernia
    • Novel gas exchange analysis in COVID-19
    • Transcriptomic landscape of diffuse radiological bronchiectasis
    Show more Editorials

    Related Articles

    Navigate

    • Home
    • Current issue
    • Archive

    About the ERJ

    • Journal information
    • Editorial board
    • Reviewers
    • Press
    • Permissions and reprints
    • Advertising

    The European Respiratory Society

    • Society home
    • myERS
    • Privacy policy
    • Accessibility

    ERS publications

    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS books online
    • ERS Bookshop

    Help

    • Feedback

    For authors

    • Instructions for authors
    • Publication ethics and malpractice
    • Submit a manuscript

    For readers

    • Alerts
    • Subjects
    • Podcasts
    • RSS

    Subscriptions

    • Accessing the ERS publications

    Contact us

    European Respiratory Society
    442 Glossop Road
    Sheffield S10 2PX
    United Kingdom
    Tel: +44 114 2672860
    Email: journals@ersnet.org

    ISSN

    Print ISSN:  0903-1936
    Online ISSN: 1399-3003

    Copyright © 2023 by the European Respiratory Society