A dobutamine test can disclose hepatosplanchnic hypoperfusion in septic patients

In 36 hemodynamically stable septic patients, we explored whether changes i n gastric mucosal-arterial PCO2 gradient (PCO(2)gap) induced by a short-ter m dobutamine infusion may reveal hepatosplanchnic hypoperfusion. Hepatospla nchnic blood flow (HSBF) was determined by the continuous indocyanine green infusion technique and gastric mucosal PCO2 (PgCO(2)) by saline tonometry. In each patient, hemodynamic measurements, blood samples, and PgCO(2) dete rminations were performed three times: first at baseline (DOB 0), second du ring a dobutamine infusion at a dose of 5 mu g/kg/min (DOB 5), and third at a dose of 10 mu g/kg/min (DOB 10). The results were analyzed by Wilcoxon's matched-pairs signed rank test and are presented as medians with ranges. T he PCO2 gap decreased preferentially in groups of patients with inadequate hepatosplanchnic perfusion, i.e., with a low fractional HSBF (HSBF/Cl), def ined as the ratio of the HSBF to the simultaneous cardiac index, or a high gradient between the mixed venous blood and the suprahepatic blood O-2 satu rations (DSvh(O2)). In the 11 patients with a DSvhO(2) above 20% at baselin e, PCO(2)gap decreased from 12.1 (6.3 to 19.5) mm Hg at DOE 0 to 6.2 (2.5 t o 19.3) mm Hg at DOE 5 (p < 0.001 versus DOE 0), and to 4.2 (0.1 to 35.9) m m Hg at DOE 10 (p < 0.05 versus DOE 5), whereas in the 25 patients with a D SvhO(2) below 20% at baseline, PCO(2)gap did not change significantly. At n o time was the PCO(2)gap correlated with HSBF/Cl or DSvhO(2). We conclude t hat although the PCO(2)gap does not correlate well with global indexes of g ut oxygenation, such a simple dobutamine infusion test could identify patie nts with inadequate hepatosplanchnic perfusion.