Central hemodynamic responses to venous, aortal or portal infusion of live E. coli bacteria in the cat.

The central hemodynamic responses were studied in experimental sepsis in cats, following various routes of infusion of live E. coli bacteria. The aortic blood flow (ABF) was electromagnetically recorded. The pulmonary artery was cannulate for pressure recording. Platelet and white blood cell concentrations, PO2, PCO2, pH and oxygen saturation were measured at intervals. I.v. infusion of bacteria induced initially decreased ABF, systemic hypotension, pulmonary hypertension. Portal infusion evoked, on the other hand, increased ABF, but induced no significant change in systemic or pulmonary arterial blood pressures. Aortal infusion induced responses in between. The initial hemodynamic changes were followed by relative normalization after 5-10 min. Then, in all series, a progressive fall in ABF and systemic blood pressure were noticed. Within 5 min following bacterial infusion the platelet and white blood cell concentrations fell to 65 and 50%, respectively. In all series a moderate metabolic acidosis developed. Thus, the initial hemodynamic response following infusion of live E. coli was dependent on the route of infusion; intraportal infusion induced initially a more hyperdynamic state. The different initial central hemodynamic responses did not influence the subsequent development of a hypotensive shock state.