The effect of dopexamine on regional tissue oxygenation, systemic inflammation and amino acid exchange in major abdominal surgery.

Abstract

Beta-adrenergic agents are frequently used to improve cardiac performance in surgical and intensive care patients. Beta-adrenergic agents have metabolic and anti-inflammatory effects in addition to their cardiovascular effects. Splanchnic metabolic activity increases in response to surgery and inflammation. Dopexamine is believed to favor blood flow distribution to the splanchnic region. We investigated the effect of dopexamine, started before major abdominal surgery, on postoperative patterns of systemic and regional blood flow, metabolic response, and markers of inflammation. Twenty-one patients undergoing major abdominal surgery were studied. All patients were stabilized preoperatively to predefined hemodynamic endpoints with fluids. After preoperative measurement of systemic and splanchnic oxygen transport and splanchnic lactate, glutamine and alanine exchange and blood levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6), the patients were randomized to receive an infusion of dopexamine at 0.5 microg kg(-1) min(-1) (group 1) or 2.0 microg kg(-1) min(-1) (group 2) or placebo. Measurements were repeated at 6 h and 24 h after the end of the operation and the blood levels of cytokines also at 36 h postoperatively. Dopexamine evoked an increase in cardiac index preoperatively. Postoperatively, there was no difference between the groups in systemic and regional hemodynamics or oxygen transport: cardiac index, splanchnic blood flow and oxygen delivery increased similarly in each group. Accordingly, systemic oxygen extraction decreased. Glutamine, alanine and lactate exchange did not differ between the groups. The only metabolic change was an increased splanchnic uptake of alanine, which also was unaffected by dopexamine. There was no difference between the groups in TNF and IL-6 levels; TNF level did not change, while IL-6 level increased in response to surgery. Dopexamine, when added to a preoperative stabilization protocol with fluids, did not augment the postoperative hemodynamic response, and had no effect on postoperative metabolic and inflammatory responses.