Comparison of dopamine to dobutamine and norepinephrine for oxygen delivery and uptake in septic shock

Objectives To test whether dopamine infusion improves oxygen delivery (DO sub 2) and oxygen uptake (VO2) in hyperdynamic septic shock patients stabilized by adequate volume and dobutamine alone, or by the combination of dobutamine and norepinephrine. Design Prospective clinical trial of two patient groups. Group 1 (n equals 15) was stabilized with dobutamine, and group 2 (n equals 10) was stabilized with dobutamine and norepinephrine. Setting Intensive care unit in a university hospital. Patients Twenty-five postoperative, hyperdynamic septic shock patients. Interventions The stabilizing catecholamine infusion was replaced in a stepwise manner by dopamine to achieve a similar mean arterial pressure (dopamine doses: group 1, mean 22 plus minus 15 micro gram/kg/min [range 6 to 52]; and group 2, mean 57 plus minus 41 micro gram/kg/min [range 15 to 130]). Measurements and Main Results A complete hemodynamic profile was performed with oxygen transport-related variables at baseline, after replacement by dopamine, and after resetting to the original catecholamine infusion. The change to dopamine resulted in increases in cardiac index (group 1: 20% [p less than .01]; group 2: 33% [p less than .01]), and DO2 (group 1: 19% [p less than .01]; group 2: 27% [p less than .01]). However, VO2, whether directly measured from the respiratory gases or calculated by the cardiovascular Fick principle, did not change in both groups with dopamine, while the oxygen extraction ratio decreased significantly in both groups with dopamine. Heart rate, pulmonary artery occlusion pressure, and pulmonary shunt fraction all increased with dopamine. PaO2 decreased, but oxygen saturation remained stable in both groups with dopamine. Conclusions Short-term dopamine infusion in hyperdynamic septic shock patients, despite producing higher global DO2, was not superior to dobutamine or the combination of dobutamine and norepinephrine infusion. (Crit Care Med 1995; 23:1962-1970)