Renovascular interaction of epinephrine, dopamine, and intraperitoneal sepsis

Objective: To determine the effect of intraperitoneal sepsis on the systemic and renal actions of the continuous infusion of epinephrine or dopamine, and during the concurrent administration of both drugs. Design: Prospective, randomized study. Setting: Laboratory at a university hospital. Subjects: Seven conscious, chronically catheterized, adult merino sheep. Interventions: Epinephrine at 40 μg/min or dopamine at 2 μg/kg/min, or both drugs concurrently were infused for 4 hrs on separate study days in healthy sheep. This protocol was then repeated following the induction of sepsis after the intraperitoneal injection of 10¹¹ Escherichia coli, 10¹² Bacteroides fragilis, and bran. Measurements and Main Results: Systemic oxygen delivery (ḊO₂) and consumption were measured using thermodilution cardiac output and measured oxygen content. Renal blood flow was measured using an electromagnetic flow transducer, and creatinine clearance was calculated as the quotient of renal blood flow and the renal extraction ratio of creatinine. Infusion of epinephrine augmented systemic ḊO₂ and mean arterial pressure (MAP) during both healthy and septic studies. Systemic oxygen consumption was only increased during epinephrine infusion in the septic study. During the healthy animal study, renal blood flow was initially decreased during epinephrine infusion, but increased to 36% above baseline (p = .003). However, creatinine clearance remained unchanged. During the experimental sepsis study, the infusion of epinephrine had less marked effects on renal blood flow (unchanged from baseline), while an initial reduction (15 mins) in creatinine clearance (p = .04) was not sustained and had returned to baseline by 3 hrs. Dopamine alone produced no change in systemic oxygen variables or MAP during the studies on healthy or septic animals. Although dopamine produced renal vasodilation and an increase in renal blood flow in the healthy state, these results were not found during the septic state. In addition, concurrent infusion of dopamine with epinephrine did not alter the systemic or renal effects of epinephrine during the healthy or septic states. Conclusions: These results do not support the routine use of low-dose dopamine, and demonstrate a change in renovascular responses to catecholamines during intraperitoneal sepsis. The infusion of epinephrine at 40 μg/min had few deleterious effects on the kidney, and augmented both MAP and systemic ḊO₂. Its role as a catecholamine in the management of septis may need to be reconsidered.