Does hepato-splanchnic Vo2/Do2 dependency exist in critically ill septic patients?

Since the gradient between the mixed venous and hepatic vein oxygen saturation (DSo(2)) is often increased in septic patients, we suspected these patients may have an imbalance between oxygen supply and demand in the hepato-splanchnic area. In 42 septic patients, hepato-splanchnic blood flow was determined by the indocyanine green clearance method with hepatic vein catheterization. The relationships between hepato-splanchnic oxygen delivery (Do(2)spla) and consumption (V(over dot)o(2)spla) were analyzed during an increase in blood flow induced by a dobutamine infusion at doses up to 10 mu g/kg min. In 14 patients, positive end-expiratory pressure (PEEP) was also increased up to 20 cm H2O. The patients were separated according to their DSo(2) (Group I: DSo(2) < 10%, n = 13; and Group II: DSo(2) > 10%, n = 29). Although Do(2)spla increased similarly in both groups, V(over dot)o(2)spla only increased in Group II (from 45 +/- 22 to 59 +/- 39 ml/mim.M-2, p < 0.01). The slope of the V(over dot)o(2)spla/Do(2)spla relationship was higher in Group II than in Group I (31.2 +/- 16.7 versus 10.4 +/- 5.1%, p < 0.001) and was similar during dobutamine and PEEP (21.9 +/- 14.2 versus 21.9 +/- 14.0%, p = NS). In conclusion, V(over dot)o(2)spla increased only in septic patients with an increased DSo(2) indicating splanchnic dysoxia. The similar slope observed with dobutamine and PEEP suggests that a thermogenic effect was unlikely.