A simple method to monitor performance of forced vital
capacity.
Volta, C. A., Y. Ploysongsang, L. Eltayara, J. Sulc, and J. Milic
-Emili.
Meakins-Christie Laboratories and Montreal Chest Institute Research
Centre, McGill University, Montreal, Quebec H2X 2P2, Canada
APStracts 2:0441A, 1995.
The FVC maneuver is the most common lung function test. One of its
major prerequisites is that it be performed with sufficient effort to
achieve the maximal flows which are due to expiratory flow
-limitation. To verify this, in 9 normal subjects short (0.25 s)
pulses of negative pressure (-5 to -20 cmH2O) were applied at the
mouth at different times (0.25-1s) after the onset of (a) FVC
maneuvers, and (b) vital capacity expirations with submaximal
expiratory efforts (SVC). All subjects were experienced in FVC
maneuvers. With FVC, the expiratory flow did not change with
application and removal of negative pressure pulses, apart from brief
flow transients, mainly reflecting displacement of air from the
compliant oral and neck structures. With SVC, flow increased
throughout the application of the negative pressure pulses. Thus,
application of pulses of negative pressure provides a simple method
for on line recognition if an FVC maneuver is performed with
sufficient effort to achieve flow-limitation.
Received 26 April 1995; accepted in final form 8 September 1995.
APS Manuscript Number A451-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95