AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 2 161-G164, Copyright © 1986 by American Physiological Society
Effects of viscosity and fluid outflow on postcibal gastric emptying of solids
J. H. Meyer, Y. Gu, J. Elashoff, T. Reedy, J. Dressman and G. Amidon
It is known that the food-filled stomach retains large spheres or pieces of
food, allowing the passage of food particles or of plastic spheres with
diameters mainly below 2 mm. We have recently shown that spheres having
densities greater or less than water emptied from the food-filled canine
stomach more slowly than spheres of the same diameter with a density of 1.
Thus, hydrodynamics seem to govern gastric emptying of spheres. The present
studies were undertaken to determine how altering other hydrodynamic
factors, viscosity and velocity of fluid outflow, might affect gastric
sieving. Ten mongrel dogs were prepared with chronic duodenal fistulas,
which allowed collecting and measuring of emptied spheres and food. The
dogs were fed a standard meal of 75 g of steak plus 25 g of 99mTc-labeled
chicken liver. Immediately afterward, 50 3.2-mm Teflon spheres were
instilled into the stomachs along with 200- or 800-ml volumes of saline or
saline plus guar (a viscous polysaccharide). Whether 200- or 800-ml volumes
were instilled, the guar significantly sped the emptying of the spheres.
Fluid outflow was twice as fast after the 800-ml instillates, but the
faster outflow with the 800 ml of saline did not speed emptying of spheres.
With the guar instillates, the faster outflow slightly sped the emptying of
the spheres and significantly increased the diameter of emptied particles
of 99mTc-labeled chicken liver. We conclude that meal viscosity
significantly affects gastric sieving.
