Splanchnic blood flow is greater in septic shock treated with norepinephrine than in severe sepsis

Objective: To assess global and splanchnic blood flow and oxygen transport in patients with sepsis with and without norepinephrine treatment. Design: Prospective, clinical study. Setting: University hospital intensive care unit. Patients: A convenience sample of 15 septic shock patients treated with norepinephrine and 13 patients with severe sepsis who did not receive norepinephrine. Measurements and main results: There were no differences between the two groups in global haemodynamics and oxygen transport. Splanchnic blood flow and oxygen delivery (splanchnic DO2 303 +/- 43 ml/min per m(2)) and consumption (splanchnic VO2 100 +/- 13 ml/min per m(2)) were much higher in the septic shock group compared with the severe sepsis group (splanchnic DO2 175 +/- 19 ml/min per m(2), splanchnic VO2 61 +/- 6 ml/min per m(2)). Gastric mucosal pH was subnormal in both groups (septic shock 7.29 +/- 0.02, severe sepsis 7.25 +/- 0.02) with no significant difference. No significant differences between groups were detected in lactate values. Conclusion: These data confirm a redistribution of blood flow to the splanchnic region in sepsis that is even more pronounced in patients with septic shock requiring norepinephrine. However, subnormal gastric mucosal pH suggested inadequate oxygenation in parts of the splanchnic region due to factors other than splanchnic hypoperfusion. Progress in this area will depend on techniques that address not only total splanchnic blood flow, but also inter-organ flow distribution, intra-organ distribution, and other microcirculatory or metabolic malfunctions.