Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. II. Effects of intraluminal hyperosmolality and simultaneous intravenous infusions.

Using an experimental model in rats a hyperosmolal glucose solution was introduced into the intestinal lumen to simulate and magnify the accumulation of fluid seen in simple small intestinal obstruction. Efforts to modify the extent and rate of this fluid flux by administering parenteral solutions of varying osmolality produced no result. When hypoosmolal or iso-osmolal infusion solutions were used, the intraluminal dilution process displayed mathematical characteristics in agreement with those of a simple dilution process, while at the same time normal blood volume was maintained. On the other hand, when a hyperosmolal glucose solution was infused, very great demands were made on the extravascular compartment, because a severe diuresis equal in volume to the fluid given parenterally took place, while at the same time there was marked hemodilution. Despite this the organism delivered as much fluid to the intestine as when hypo-osmolal or iso-osmolal infusions were given. Thus in principle the flow of fluid into the intestinal lumen could not be modified by giving parenteral solutions of any osmolality.