Journal of Applied Physiology, Vol 52, Issue 4 874-878, Copyright © 1982 by American Physiological Society
Bronchodilatation, lung recoil, and density dependence of maximal expiratory flow
J. W. Weiss, E. R. McFadden Jr and R. H. Ingram Jr
Using normal human subjects we have measured maximal expiratory flow rates
with air (Vmaxair) and after a washin of 80% He-20% O2 (VmaxHeO2) and
static elastic recoil pressures of the lung [Pst(L)] both before and after
administration of a beta-agonist, terbutaline. The effects of inhaled drug
were compared with those of the subcutaneously administered agent, each
given in doses to produce maximal bronchodilatation as assessed by
increases in Vmaxair in the mid-vital capacity. Although there was a
significant yet modest decrease in Pst(L) only after injection of the
agent, density dependence (DD), assessed as the ratio of VmaxHeO2 to
Vmaxair, increased significantly and comparably after either route of
administration. A modest decrease in Pst(L), therefore, did not affect the
changes in DD.
