Effect of a dopexamine-induced increase in cardiac index on splanchnic hemodynamics in septic shock

In 12 patients with hyperdynamic septic shock we studied the effect of dopexamine, a combined dopamine and beta-adrenergic agonist, on hepatosplanchnic hemodynamics and O-2 exchange. All patients required noradrenaline to maintain mean arterial pressure > 60 mm Hg (noradrenaline greater than or equal to 0.04 mu g . kg(-1) . min(-1)) with a cardiac index greater than or equal to 3.0 L/min/m(2). Splanchnic blood flow ((Q) over dot spl) was measured using primed continuous infusion of indocyanine green dye with hepatic venous sampling. In addition tonometric gastric mucosal-arterial and gastric mucosal-hepatic venous Pco(2) gradients were assessed as indicators of regional energy balance. After 90 min of stable hemodynamics a first measurement was obtained. Then dopexamine infusion was titrated (1-4 mu g . kg-(1) . min-(1)) to increase cardiac output by approximately 25% (20-30%). After 90 min all measurements were repeated, and dopexamine was withdrawn followed by a third measurement. Median (Q) over dot spl (0.86/1.23-0.66 versus 0.96/1.42-0.85 L/min/m(2) [median value/25th-75th percentiles], p < 0.05) increased whereas the fractional contribution of (Q) over dot spl to total blood flow decreased (21/28-13 versus 19/28-12%, p < 0.05). Although both global and regional oxygen delivery (Do(2)) consistently increased, neither global or regional (V) over dot nor Pco(2) gradients were significantly affected. In patients with septic shock and ongoing noradrenaline treatment dopexamine seems to have no preferential effects on hepatosplanchnic hemodynamics, O-2 exchange, or energy balance.