Pulmonary blood flow distribution has a hilar-to-peripheral
gradient in awake, prone sheep.
Walther, Sten M, Karen B Domino, Robb W Glenny, Nayak L Polissar, and
Michael P Hlastala.
Departments of Anesthesiology, Physiology and Biophysics, and
Medicine, University of Washington School of Medicine, Seattle, WA
98195
APStracts 3:0484A, 1996.
We examined the pulmonary blood flow distribution with intravenous
fluorescent microspheres (15 [mu]m) in nine prone, unanesthetized,
lambs. Lungs flushed free of blood, were air-dried at total lung
capacity and sectioned into 2 cm3 pieces. The pieces were weighed,
identified by lobe and assigned spatial coordinates. Fluorescence was
read on a spectrophotometer, signals were corrected for piece weight
and normalized to mean flow. Pulmonary blood flow heterogeneity was
assessed using the coefficient of variation of the flow data. The
number of pieces analyzed were 1249 +/- 150 (mean +/- SD) per animal.
Heterogeneity of blood flow was 29.5 +/- 6.5% (coefficient of
variation = SD/mean). Pulmonary blood flow decreased with distance
from hilus (P<0.002), but did not change significantly with
vertical height. Distance from the hilus was the best predictor of
pulmonary blood flow (R2 = 0.201), and together with spatial
coordinates and lobe accounted for 33.7 +/- 12.0% of blood flow
variability. We conclude that pulmonary blood flow in the awake,
prone sheep is distributed with a hilar-to-peripheral gradient, but
no significant vertical gradient.
Received 21 December 1995; accepted in final form 18 October
1996.
APS Manuscript Number A1334-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996