Journal of Applied Physiology, Vol 48, Issue 4 619-623, Copyright © 1980 by American Physiological Society
Effects of atropine on respiratory heat loss in asthma
F. J. Breslin, E. R. McFadden Jr, R. H. Ingram Jr and E. C. Deal Jr
We have previously observed that although atropine does not alter the
magnitude of the response to exercise while breathing cold air, it does
cause the predominant site of obstruction to move into the lung periphery.
To determine if this effect was due to changes in the conditioning of
inspired air, we measured respiratory heat loss (RHL) and retrotracheal
(Trt) and retrocardiac esophageal temperature in eight asthmatics while
they performed eucapnic hyperventilation with cold air before and after the
inhalation of atropine. Multiple aspects of pulmonary mechanics were also
recorded. Significant and equivalent airway obstruction developed with and
without atropine (control delta FEV1 = 1.0 +/- 0.2 (SE) liter; postatropine
= 0.9 +/- 0.3 liter). Despite this, RHL was 17.1% greater and Trt fell 16%
more after atropine. These data demonstrate that atropine can influence
heat transfer within the lung and alter the sites of conditioning.
