Temporal heterogeneity of regional pulmonary perfusion is spatially
clustered.
Glenny, Robb W., Nayak L. Polissar, Steven McKinney, H. Thomas
Robertson.
Division of Pulmonary and Critical Care Medicine Department of
Medicine, University of Washington
APStracts 2:0237A, 1995.
This study investigates temporal changes in regional pulmonary
perfusion. Five dogs were studied with five or six different radio
-labeled microspheres being injected via a central vein over 30
seconds every 20 minutes. The lungs of each animal were cubed into
1.9 cm3 pieces with spatial coordinates noted for each piece. Within
individual pieces, the CV of regional perfusion over time was 17.2
+/- 6.8% (mean +/- SD) and across dogs accounted for 7.26 +/- 5.7% of
total perfusion heterogeneity. Temporal variability or
"twinkling" was not random. When lung pieces with similar
temporal flow patterns were grouped together (regardless of spatial
location), groups were more tightly clustered in space than expected
by chance. Statistical clustering methods revealed regulation of
blood flow on a large scale (lobar arteries) and fractal analyses
suggested regulation existed on a smaller scale (arterioles). We
conclude that regional pulmonary perfusion is heterogeneous over time
in a non-random pattern and that pieces clustered by temporal
patterns of perfusion are neighbors in the spatial domain.
Received 19 December 1994; accepted in final form 8 May 1995.
APS Manuscript Number A1284-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 June 1995.