Journal of Applied Physiology, Vol 52, Issue 5 1128-1132, Copyright © 1982 by American Physiological Society
Effect of baroreceptor reflex stimulation on blood flow to an atelectatic lung
W. B. Strawn, S. M. Hall and M. G. Levitzky
The effect of baroreceptor reflex stimulation by carotid sinus hypotension
on the pulmonary vascular response to atelectasis was studied in eight dogs
anesthetized with chloralose. Closed-chest dogs with electromagnetic flow
probes previously implanted on their left (QL) and main (QT) pulmonary
arteries had their left and right lungs ventilated separately. Their
carotid sinuses were isolated bilaterally and perfused by a pulsatile pump
with a physiological salt solution. After an initial period of bilateral
100% O2 ventilation with carotid sinus perfusion pressures (CSPP) set at
each animal's initial mean arterial pressure (98 +/- 19 Torr), the left
airway was occluded, QL/QT fell from 0.33 +/- 0.01 to 0.24 +/- 0.02 and PO2
fell from 323 +/- 35 Torr to 74 + 7 Torr. When CSPP was lowered to 21 +/- 3
Torr, there were no changes in QL/QT and PO2. These results suggest that
stimulation of the baroreceptor reflex by carotid sinus hypotension does
not interfere with the diversion of pulmonary blood flow away from a
unilaterally atelectatic lung.
