Norepinephrine and vital organ blood flow during experimental hyperdynamic sepsis.

OBJECTIVE: To study the effect of norepinephrine (NE) infusion on cerebral, coronary, renal and mesenteric blood flow during sepsis.

DESIGN AND SETTING: Randomised placebo-controlled animal trial in the animal laboratory of university physiology institute.

ANIMALS: Seven merino cross-ewes.

INTERVENTIONS: Chronic implantation of flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous bolus of E. coli (3 x 10(9)). After the onset of hyperdynamic sepsis sheep were randomly allocated to either NE (0.4 microg kg(-1) min(-1)) or placebo for 6 h.

MEASUREMENTS AND RESULTS: E. coli induced hypotension, fever, oliguria, tachycardia and tachypnoea. It increased cardiac output and renal, mesenteric and coronary blood flows. Sagittal flow remained unchanged. Compared to placebo NE infusion restored mean arterial blood pressure and further increased cardiac output. The increases in renal, mesenteric and coronary blood flow were unaffected. Sagittal flow was also unaltered. Compared to placebo NE increased myocardial performance, mean urine output and creatinine clearance at 2 h.

CONCLUSIONS: We conclude that hyperdynamic sepsis increases blood flow to heart, gut and kidney and that NE further increases cardiac output, blood pressure, myocardial performance, and urine output and creatinine clearance while maintaining regional blood flow.