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

OBJECTIVES

To test whether dopamine infusion improves oxygen delivery (Do2) 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 = 15) was stabilized with dobutamine, and group 2 (n = 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 +/- 15 micrograms/kg/min [range 6 to 52]; and group 2, mean 57 +/- 41 micrograms/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 < .01]; group 2: 33% [p < .01]), and DO2 (group 1: 19% [p < .01]; group 2: 27% [p < .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.