Journal of Applied Physiology, Vol 51, Issue 6 1457-1462, Copyright © 1981 by American Physiological Society
Shape and regional volume in immersed lung lobes
D. Gillett, G. T. Ford and N. R. Anthonisen
We froze 10 isolated canine lower lobes by immersing them in chlorothene
(sp gr 1.4) at -20 degrees C. In six instances the contralateral lower lobe
was frozen over dry ice. The lobes were then sliced horizontally, and the
volume and weight of each slice were measured so that expansion (specific
volume) and the amount of tissue (weight) could be assessed as a function
of distance down the lung. Lobes frozen under chlorothene at low [35% total
lung capacity (TLC)] and medium [60% TLC] volumes demonstrated a gradient
of regional expansion that was about half that predicted on the basis of
pleural surface pressure. Lobes frozen under chlorothene at high volumes
[80% TLC] did not demonstrate a significant gradient of regional expansion.
These results demonstrated tissue interdependence. When lobes frozen under
chlorothene were compared with contralateral lobes frozen over dry ice,
substantial differences in shape were evident. Chlorothene-frozen lobes had
greater vertical height, and a smaller fraction of their weight was present
in dependent regions: lobes frozen in chlorothene had half as much tissue
over the lower 40% of their vertical height as did lobes frozen over dry
ice. We demonstrated two mechanisms by which relative homogeneity of
regional expansion was maintained in response to differences in pleural
pressure, tissue interdependence and tissue movement from more compressed
to less compressed regions.
