Distribution of pulmonary and bronchial blood supply to airways
measured by fluorescent microspheres.
Bernard, S. L., R. W. Glenny, N. L. Polissar, D. L. Luchtel, and S.
Lakshminarayan.
University of Washington and the VA Medical Center, Division of
Pulmonary and Critical Care Medicine, Seattle, Washington, 98195
APStracts 2:0412A, 1995.
This study determined the relative contributions of systemic
(bronchial) and pulmonary blood flow to the intraparenchymal airways
greater than 1 mm in diameter using fifteen-micrometer fluorescent
microspheres and fluorescence microscopy in four dogs. Fluorescent
microspheres of one color were injected into the inferior vena cava
as a pulmonary blood flow marker, and fluorescent microspheres of
another color were injected into the left ventricle as a systemic
blood flow marker. After the second injection the animals were
killed, the lungs excised and air dried at total lung capacity. The
left lung was sliced into transverse planes and then sectioned into
smaller blocks containing airways down to 1 mm in diameter. The
blocks were then sectioned using a Vibratome_ and examined with a
fluorescence microscope. Pulmonary and systemic blood flow markers
were counted in airway walls and the diameter of each airway was
measured to determine the bronchial tissue volume. After correcting
for the number of blood flow markers injected into each circulation,
the average ratio of pulmonary to systemic blood flow markers seen in
airway walls was 1:37 indicating that 97% of the blood supply to the
intraparenchymal airways down to 1 mm in diameter is from the
bronchial circulation. Furthermore, based on a weighted least squares
regression analysis, systemic (bronchial) blood flow per unit tissue
volume increased as airway diameter decreased (p=0.03).
Received 7 December 1994; accepted in final form 8 September
1995.
APS Manuscript Number A1244-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 31 October 95