Journal of Applied Physiology, Vol 46, Issue 4 658-661, Copyright © 1979 by American Physiological Society
Demonstration of interlobar collateral ventilation
T. S. Scanlon and J. L. Benumof
In an ongoing series of experiments on mongrel dogs, three dogs were
observed to have incomplete lobar fissures (interlobar connection present)
between the left upper and left lower lobes. With the interlobar connection
unclamped, selective hypoxia of the left lower lobe caused the
electromagnetically measured blood flow to the left lower lobe to decrease
41 +/- 4%, whereas with the interlobar connection clamped selective hypoxia
of the left lower lobe caused a 52 +/- 4% decrease in left lower lobe flow
(P less than 0.05). Following 100% O2 ventilation and with the interlobar
connection unclamped, complete occlusion of the left lower lobe bronchus
caused no atelectasis or decrease in left lower lobe blood flow, whereas
with the interlobar connection clamped complete occlusion of the left lower
lobe bronchus caused complete left lower lobe atelectasis and a 58 +/- 3%
decrease in left lower lobe blood flow. Histological confirmation of
interlobar pulmonary parenchymal connection was obtained in each dog. We
conclude that a sufficient amount of interlobar collateral ventilation can
occur in dogs with incomplete lobar fissures to prevent absorption
atelectasis and alter lobar blood flow reduction usually caused by
selective lobar hypoxia.
