Increasing splanchnic blood flow in the critically III.
OBJECTIVE
To assess the effect of low dose dopexamine and dopamine on splanchnic blood flow as measured by gastric intramucosal pH, hepatic metabolism of lidocaine (lignocaine) to monoethylglycinexy-lidide (MEGX), and plasma disappearance rate of indocyanine green (ICG).


METHODS
Single-blind randomization of patients with a gastric intramucosal acidosis to receive dopexamine (ten patients), dopamine (ten patients), or saline solution (five control patients) for 2 h.


METHODS
All 25 patients were in the ICU of Guys' Hospital.


METHODS
All patients met the criteria for the diagnosis of the systemic inflammatory response syndrome, were mechanically ventilated, and had pulmonary artery catheters placed. All had a low gastric intramucosal pH and had a median first 24-h acute physiology and chronic health evaluation (II) score of 22 (range, 7 to 40).


METHODS
Baseline measurements of gastric intramucosal pH, MEGX formation from lidocaine, ICG plasma disappearance rate, heart rate, mean arterial pressure, pulmonary artery occlusion pressure, cardiac index, oxygen delivery index, oxygen uptake index, systemic vascular resistance, and arterial pH were taken. Dopexamine (1 mg.kg-1.min-1), dopamine (2.5 mg.kg-1.min-1), or 0.9% saline solution was then infused for 2 h, after which a repeated set of the measurements was taken.


RESULTS
Dopexamine at a low dose had no effect on any of the systemic measurements. The median intramucosal pH rose from 7.23 to 7.35 (p < 0.005), the median ICG plasma disappearance rate from 7.6 to 11.3%.min-1 (p < 0.02), and the median MEGX concentration from 4 to 10.2 ng.mL-1 (p < 0.005). Dopamine had no effect on any of the measured variables. There were no changes in the control group.


CONCLUSIONS
Low-dose dopexamine increases splanchnic blood flow as measured by gastric intramucosal pH, MEGX formation from lidocaine, and ICG clearance. The lack of any change in the systemic measurements suggests that these effects are the result of a selective vasodilatation of the splanchnic vessels. At the dose used in this study, dopamine had no effect on splanchnic blood flow. Dopexamine may be useful in the management of splanchnic ischemia in the critically ill.
D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000493:pharmacokinetics; D004396:Coloring Agents / Q000493:pharmacokinetics; D016638:Critical Illness; D004298:Dopamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology*; D005753:Gastric Mucosa / Q000378:metabolism; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007208:Indocyanine Green / Q000493:pharmacokinetics; D008012:Lidocaine / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000503:physiopathology; D016037:Single-Blind Method; D013152:Splanchnic Circulation / Q000187:drug effects*; D018746:Systemic Inflammatory Response Syndrome / Q000378:metabolism / Q000503:physiopathology*
D000779:Anesthetics, Local; D004396:Coloring Agents; D018491:Dopamine Agonists; C046318:dopexamine; D008012:Lidocaine; C001173:monoethylglycinexylidide; D007208:Indocyanine Green; D004298:Dopamine