Intestinal hemodynamic effects of varying the route of infusion of live E. coli bacteria in the cat.

The responses of the series-coupled vascular sections in the feline small intestine were studied in experimental sepsis induced following various routes of infusion of live E. coli bacteria. The intestinal hemodynamics were followed by means of plethysmography combined with direct recording of the intestinal venous outflow. After 2 hours of bacterial infusion the experiments were terminated. Infusion of E. coli in the inferior caval vein induced initially hypotension, decreased intestinal blood flow (Q) and increased intestinal vascular resistance (R). Portal venous infusion induced, on the other hand, an initial arterial blood pressure increase, an increase of Q and a decrease of R. Aortal infusion evoked only minor initial changes. The early response was in all series followed by a progressive hypotension during which Q decreased and R increased gradually. There were no changes in intestinal tissue volume, indicating that there was no pooling of blood or extravasation of fluid, during the experiments. Intestinal mucosal lesions were equally distributed in the three series. Thus, depending on the route of infusion live E. coli induced intestinal vasoconstriction or vasodilatation. Regardless the route, there was no intestinal pooling of blood or fluid. Hypotension developed in most cats after 120 min, regardless the site of infusion and the initial vascular response.