Effect of postoperative low-dose dopamine on renal function after elective major vascular surgery

Abstract

Objective: To determine the effect on renal function of postoperative low-dose dopamine in volume-replete patients after elective, major vascular abdominal surgery.

Design: Randomized, double-blind, placebo-controlled trial.

Setting: Intensive care unit of a referral hospital in Brisbane, Australia.

Patients: 37 patients having elective repair of an abdominal aortic aneurysm or having aortobifemoral grafting; 18 received dopamine, and 19 received placebo. Two patients were excluded from the 5-day analysis because of perioperative death.

Interventions: Patients were randomly assigned to receive either placebo or a low-dose infusion of dopamine (3 micrograms/kg per minute) in saline. Patients in both groups were given sufficient crystalloid to maintain a urine flow of more than 1 mL/kg per hour during the first 24 postoperative hours. Care in the intensive care unit was otherwise usual and was the same for each group.

Measurements: Plasma creatinine levels, urea levels, and creatinine clearance were measured preoperatively and postoperatively (at 24 hours and 5 days). Urine flow and the volume of crystalloid during the first 24 hours were recorded.

Results: Two postoperative deaths occurred in the dopamine group (from renal failure and myocardial infarction). Four patients had myocardial infarction, three of whom received dopamine. Plasma creatinine levels remained unchanged in both groups. At 24 hours, the mean plasma urea level decreased by 1.07 mmol/L in the dopamine group compared with 1.84 mmol/L in the placebo group, a difference of 0.77 (95% CI, -0.12 to 1.67). The mean 24-hour creatinine clearance increased by 0.165 mL/s (9.89 mL/min) in the dopamine group and by 0.199 mL/s (11.98 mL/min) in the placebo group (P > 0.2). Urine volumes were slightly higher in those receiving dopamine (1.83 mL/kg compared with 1.6 mL/kg, a difference of 0.23 [CI, -0.18 to 0.64]). None of these differences were statistically or clinically significant.

Conclusions: Within the limits of the small size of the study, low-dose dopamine appeared to offer no advantage to euvolemic patients after elective abdominal aortic surgery. However, patients with acute oliguric renal failure were not included in the study.