Detection of expiratory flow limitation during exercise in COPD patients

• Published in: Journal of applied physiology (1985) Vol. 82; no. 3; pp. 723 - 731
• Main Authors: Koulouris, Nickolaos G, Dimopoulou, Ioanna, Valta, Paivi, Finkelstein, Richard, Cosio, Manuel G, Milic-Emili, J
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.03.1997; American Physiological Society
• Subjects: Adult; Aged; Biological and medical sciences; Chronic obstructive pulmonary disease, asthma; Exercise - physiology; Female; Humans; Lung Diseases, Obstructive - physiopathology; Male; Medical sciences; Middle Aged; Pneumology; Pulmonary Ventilation - physiology; Physical exercise; Human; Lung disease; Chronic; Physical performance; Respiratory disease; Limitation; Bicycle ergometer; Bronchus disease; Obstructive pulmonary disease; Expiratory flow rate
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1997.82.3.723

Nickolaos G. Koulouris, Ioanna Dimopoulou, Päivi Valta, Richard Finkelstein, Manuel G. Cosio, and J. Milic-Emili Meakins-Christie Laboratories and Respiratory Division, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada H2X 2P2 Received 5 September 1995; accepted in final form 22 October 1996. Koulouris, Nickolaos G., Ioanna Dimopoulou, Päivi Valta, Richard Finkelstein, Manuel G. Cosio, and J. Milic-Emili. Detection of expiratory flow limitation during exercise in COPD patients. J. Appl. Physiol. 82(3): 723-731, 1997. The negative expiratory pressure (NEP) method was used to detect expiratory flow limitation at rest and at different exercise levels in 4 normal subjects and 14 patients with chronic obstructive pulmonary disease (COPD). This method does not require performance of forced expirations, nor does it require use of body plethysmography. It consists in applying negative pressure ( 5 cmH 2 O) at the mouth during early expiration and comparing the flow-volume curve of the ensuing expiration with that of the preceding control breath. Subjects in whom application of NEP does not elicit an increase in flow during part or all of the tidal expiration are considered flow limited. The four normal subjects were not flow limited up to 90% of maximal exercise power output ( max ). Five COPD patients were flow limited at rest, 9 were flow limited at one-third max , and 12 were flow limited at two-thirds max . Whereas in all patients who were flow limited at rest the maximal O 2 uptake was below the normal limits, this was not the case in most of the other patients. In conclusion, NEP provides a rapid and reliable method to detect expiratory flow limitation at rest and during exercise. negative expiratory pressure; chronic obstructive pulmonary disease; exercise performance; dynamic hyperinflation 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society