You are here

Article Text

Article menu

Download PDFPDF

Original articles
Evidence for expiratory flow limitation of extrathoracic origin in patients with obstructive sleep apnoea
Free
  1. E Verin1,
  2. C Tardif1,
  3. F Portier2,
  4. T Similowski3,
  5. P Pasquis1,
  6. J F Muir2
  1. 1Service de Physiologie Respiratoire et Sportive, CHU de Rouen, Hopital de Bois Guillaume-1 rue de Germont, 76031 Rouen Cedex, France
  2. 2Service de Pneumologie, CHU de Rouen, Hopital de Bois Guillaume, 1 rue de Germont, 76031 Rouen Cedex, France
  3. 3Service de Pneumologie et de Réanimation, Groupe Hospitalier Pitié-Salpêtriére, 47–83 Boulevard de l'Hôpital, 75651 Paris Cedex 13, France
  1. Correspondence to:
    Dr E Verin, Service de Physiologie Respiratoire et Sportive, CHU de Rouen, Hopital de Bois Guillaume, 1 rue de Germont, 76031 Rouen Cedex, France;
    eric.verin{at}free.fr

Abstract

Background: A study was undertaken to examine the expiratory flow response to a negative pressure (NEP) applied at the airway in patients with no abnormalities of the intrathoracic airway but suffering from the obstructive sleep apnoea syndrome (OSAS).

Methods: Nineteen patients with OSAS with normal spirometric values were studied. NEP of –5 cm H2O and –10 cm H2O was applied to the mouth when sitting and when supine.

Results: Thirteen patients exhibited expiratory flow limitation when supine (group 1). Of these, three also had flow limitation in the sitting position. The remaining six patients (group 2) had no flow limitation. Patients in groups 1 and 2 were similar with respect to age, sex, and body mass index, but the apnoea/hypopnoea index (AHI) was higher in group 1 than in group 2 (p<0.05). There was a significant correlation between the degree of flow limitation (expressed as a percentage of the expired tidal volume over which the NEP induced flow did not exceed spontaneous flow) and the AHI (p<0.05 for both pressure levels) as well as the desaturation index (DI, number of desaturations per hour of sleep; p<0.05 at –10 cm H2O).

Conclusion: This study confirms that the NEP technique can detect expiratory flow limitation of extrathoracic as well as of intrathoracic origin. This technique could be useful for studying the collapsibility of the passive upper airway in awake subjects and might help to predict the severity of OSAS.

  • obstructive sleep apnoea syndrome
  • negative expiratory pressure
  • expiratory flow limitation

https://doi.org/10.1136/thorax.57.5.423

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    View Full Text

    Footnotes

    • Funding: This study was supported in part by ADOREP (Association pour le Développement et l'Organisation de la Recherche en Pneumologie) Paris, France.