Renal effects of norepinephrine in septic and nonseptic patients

Objective: To assess the effects of a norepinephrine-induced vasoconstriction on renal function in septic and nonseptic patients. Design: Open-label prospective study. Setting: Medical-surgical ICU in an urban teaching hospital. Patients: Fourteen patients with septic shock and 12 uninfected patients with head trauma (Glasgow coma score, < 8). Interventions: Patients received norepinephrine infusion to increase systemic vascular resistance index (SVRI), and to raise mean arterial BP (MAP) to > 70 mm Hg in the septic group and cerebral perfusion pressure (CPP) to > 70 min Hg in the head trauma group. Measurements and main results: MAP and SVRI increased in both groups (p < 0.001), and CPP significantly increased in the head trauma group (p < 0.001). The cardiac index was not modified in either group. Norepinephrine infusion reestablished urine flow in 12 of the 14 septic patients (p < 0.001), with a decrease in serum creatinine levels (p < 0.001) and an increase in creatinine clearance rate (p < 0.001) after 24 h. Urine parameters were not affected in the head trauma group. Conclusion: Within the limitation of the present study, norepinephrine administration induces a marked vasoconstriction in septic and nonseptic patients. Norepinephrine has positive effects on renal function in septic patients but has no significant effect on the same urinary parameters when administered to uninfected patients with normal renal function.