AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 3 451-G457, Copyright © 1989 by American Physiological Society
Time-related changes in microsphere entrapment in canine jejunum
I. Prokopiw, P. K. Dinda and I. T. Beck
Department of Medicine, Queen's University, Hotel Deiu Hospital, Kingston, Ontario, Canada.
To assess the validity of repeated blood flow measurements using the
microsphere technique, the apparent blood flows in the anatomic layers of
the jejunum were determined from the entrapment of 9-, 11.5-, and 17-micron
microspheres at 1.5, 15, 30, and 60 min after their injection. The
entrapment of 17-micron spheres in the mucosa plus submucosa and in the
muscularis propria remained similar at all times, but these spheres
migrated (P less than 0.01) from the submucosa to the mucosa. By 1.5 min, 5
+/- 2% of 11.5-micron spheres had shunted, but no subsequent shunting was
observed. No migration of 11.5-micron spheres from the mucosa, submucosa or
the muscularis was observed. The shunting of 9-micron spheres from the
whole wall increased from 19 +/- 4% at 1.5 min to 40 +/- 4% at 60 min (P
less than 0.001). These data suggest that 17-micron spheres can only
fractionate the blood flow of the whole wall into that of the mucosa plus
submucosa and that of the muscularis propria, while 11.5-micron spheres may
measure fractional flow to the submucosa separately. The continued washout
of 9-micron microspheres precludes their use for repeated blood flow
measurements.
