RENOVASCULAR INTERACTION OF EPINEPHRINE, DOPAMINE, AND INTRAPERITONEAL SEPSIS

Objective: To determine the effect of intraperitoneal sepsis on the sy stemic and renal actions of the continuous infusion of epinephrine or dopamine, and during the concurrent administration of both drugs. Desi gn: Prospective, randomized study. Setting: Laboratory at a university hospital. Subjects: Seven conscious, chronically catheterized, adult merino sheep. Interventions: Epinephrine at 40 mu g/min or dopamine at 2 mu g/kg/min, or both drugs concurrently were infused for 4 hrs on s eparate study days in healthy sheep. This protocol was then repeated f ollowing the induction of sepsis after the intraperitoneal injection o f 10(11) Escherichia coli, 10(12) Bacteroides fragilis, and bran. Meas urements and Main Results: Systemic oxygen delivery (Do(2)) and consum ption were measured using thermodilution cardiac output and measured o xygen content. Renal blood flow was measured using an electromagnetic flow transducer, and creatinine clearance was calculated as the quotie nt of renal blood flow and the renal extraction ratio of creatinine. I nfusion of epinephrine augmented systemic DO2 and mean arterial pressu re (MAP) during both healthy and septic studies. Systemic oxygen consu mption was only increased during epinephrine infusion in the septic st udy. During the healthy animal study, renal blood flow was initially d ecreased during epinephrine infusion, but increased to 36% above basel ine (p = .003). However, creatinine clearance remained unchanged. Duri ng the experimental sepsis study, the infusion of epinephrine had less marked effects on renal blood flow (unchanged from baseline), while a n initial reduction (15 mins) in creatinine clearance (p = .04) was no t sustained and had returned to baseline by 3 hrs. Dopamine alone prod uced no change in systemic oxygen variables or MAP during the studies on healthy or septic animals. Although dopamine produced renal vasodil ation and an increase in renal blood flow in the healthy state, these results were not found during the septic state. In addition, concurren t infusion of dopamine with epinephrine did not alter the systemic or renal effects of epinephrine during the healthy or septic states. Conc lusions: These results do not support the routine use of low-dose dopa mine, and demonstrate a change in renovascular responses to catecholam ines during intraperitoneal sepsis. The infusion of epinephrine at 40 mu g/min had few deleterious effects on the kidney, and augmented both MAP and systemic be,. Its role as a catecholamine in the management o f septis may need to be reconsidered.