EFFECT OF POSTOPERATIVE LOW-DOSE DOPAMINE ON PENAL FUNCTION AFTER ELECTIVE MAJOR VASCULAR-SURGERY

Objective: To determine the effect on renal function of postoperative low-dose dopamine in volume-replete patients after elective, major vas cular abdominal surgery. Design: Randomized, double-blind, placebo-con trolled 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 recei ved dopamine, and 19 received placebo. Two patients were excluded from the 5-day analysis because of perioperative death. Interventions: Pat ients were randomly assigned to receive either placebo or a low-dose i nfusion of dopamine (3 mu g/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. Ca re 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 dur ing the first 24 hours were recorded.Results: Two postoperative deaths occurred in the dopamine group (from renal failure and myocardial inf arction). Four patients had myocardial infarction, three of whom recei ved dopamine. Plasma creatinine levels remained unchanged in both grou ps. At 24 hours, the mean plasma urea level decreased by 1.07 mmol/L i n the dopamine group compared with 1.84 mmol/L in the placebo group, a difference of 0.77 (95% Cl, -0.12 to 1.67). The mean 24-hour creatini ne clearance increased by 0.165 mL/s (9.89 mL/min) in the dopamine gro up and by 0.199 mL/s (11.98 mL/min) in the placebo group (P > 0.2). Ur ine volumes were slightly higher in those receiving dopamine (1.83 mL/ kg compared with 1.6 mL/kg, a difference of 0.23 Cl, -0.18 to 0.64). None of these differences were statistically or clinically significan t. Conclusions: Within the limits of the small size of the study, low- dose dopamine appeared to offer no advantage to euvolemic patients aft er elective abdominal aortic surgery. However, patients with acute oli guric renal failure were not included in the study.