Detection of expiratory flow limitation during exercise in copd
patients.
Koulouris, Nickolaos G., Ioanna Dimopoulou, P[umlaut]aivi Valta,
Richard Finkelstein, Manuel G. Cosio, and J. Milic-Emili.
Meakins-Christie Laboratories and Respiratory Division, Royal
Victoria Hospital, McGill University, Montreal, Quebec H2X 2P2,
Canada
APStracts 3:0516A, 1996.
The Negative Expiratory Pressure (NEP) method was used to detect
expiratory flow limitation at rest and different exercise levels in 4
normal subjects and 14 COPD patients. This method does not require
performance of forced expirations, nor use of body plethysmography.
It consists in applying negative pressure (-5 cmH2O) 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 4 normals were not flow-limited up to 90% of maximal
exercise power output (max). Five COPD patients were flow-limited at
rest, 9 at 1/3 max, and 12 at 2/3 max. Whilst in all patients who
were flow-limited at rest the maximal O2 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.
Received 5 September 1995; accepted in final form 22 October
1996.
APS Manuscript Number A957-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996