Differential effects of dopamine, dopexamine, and dobutamine on jejunal mucosal perfusion early after cardiac surgery.

OBJECTIVE: To evaluate the potential differential effects of dopamine, dopexamine, and dobutamine on jejunal mucosal perfusion, assessed by endoluminal laser Doppler flowmetry in uncomplicated postcardiac surgical patients.

DESIGN: A prospective, blinded, randomized, crossover study.

SETTING: A cardiothoracic intensive care unit in a tertiary care center.

PATIENTS: A total of ten postoperative cardiac surgical patients were studied.

INTERVENTIONS: Each patient received sequentially, randomly, and in a blinded fashion 2.7+/-0.2 microg x kg(-1) x min(-1) dopamine, 0.7+/-0.1 microg x kg(-1) x min(-1) dopexamine, and 2.7+/-0.1 microg x kg(-1) x min(-1) dobutamine. Each inotropic agent was titrated to increase cardiac output by 25% from baseline. Data on jejunal mucosal perfusion, splanchnic lactate, and oxygen extraction were obtained during a 5-min control period and a 5-min drug infusion period after the target cardiac output was reached. The procedure was sequentially repeated for each agent, and there was a 20- to 30-min washout period between each agent.

MEASUREMENTS AND MAIN RESULTS: Dopamine, dopexamine, and dobutamine increased jejunal mucosal perfusion by 27% (p < .01), 20% (p < .001), and 7% (p < .001), respectively. The increase in jejunal mucosal perfusion by dopamine and dopexamine were significantly more pronounced compared with dobutamine (p < .05 and p < .01, respectively), whereas there was no difference between dopamine and dopexamine. Splanchnic oxygen extraction decreased to the same extent with all three drugs. Splanchnic lactate extraction did not change for any of the drugs. The effects on central hemodynamics were similar for the three inotropic agents.

CONCLUSIONS: Endoluminal laser Doppler flowmetry is a new tool for the detection of perfusion changes at the local intestinal mucosal level. Dopamine, dopexamine, and dobutamine have differential effects on jejunal mucosal perfusion probably because of their different receptor stimulating properties. These findings may be of clinical importance when the therapeutic goal is to improve gut mucosal perfusion.