The Contrasting Effects of Dopamine and Norepinephrine on Systemic and Splanchnic Oxygen Utilization in Hyperdynamic Sepsis

Abstract

OBJECTIVE: To compare the effects of dopamine and norepinephrine on systemic and splanchnic oxygen utilization in patients with hyperdynamic sepsis. DESIGN: A randomized short-term, interventional study. SETTING: An intensive care unit of a university hospital. PATIENTS: Twenty septic patients with a cardiac index greater than 3.2 L-min-1.m-2 and either a mean arterial pressure (MAP) less than 60 mm Hg or a systemic vascular resistance index less than 1200 dyne.s.cm-5.m-2. METHODS AND INTERVENTIONS: Patients were randomized to receive an infusion of either dopamine or norepinephrine titrated to increase the MAP to greater than 75 mm Hg. The hemodynamic profile, oxygen delivery, oxygen consumption (determined by indirect calorimetry), and gastric intramucosal pH (pHi) (determined by gastric tonometry) were determined at baseline and after 3 hours of achieving the target MAP. RESULTS: Dopamine increased the MAP largely by increasing the cardiac index whereas norepinephrine increased the MAP by increasing the systemic vascular resistance index while maintaining the cardiac index. Although oxygen delivery and oxygen consumption increased in both groups of patients, the pHi increased significantly in those patients treated with norepinephrine whereas the pHi decreased significantly in those patients receiving dopamine (P < .001, for corrected 3-hour value). CONCLUSIONS: This study suggests that dopamine may cause an uncompensated increase in splanchnic oxygen requirements in septic patients. Norepinephrine, however, may have a more favorable hemodynamic profile and improve splanchnic tissue oxygen utilization in sepsis.