In patients with normal heart and kidney functions following routine coronary artery surgery was to investigate the effect of ‘renal dose’ dopamine on renal tubular function.

Methods:

Forty patients were prospectively randomised into two equal groups. The patients in Group 1 (n = 20) received dopamine infusion at renal dose ( 2.5 – 4.0 µg/kg per min ) starting from induction of anaesthesia for 48 hours, whereas the other group (Group 2, n = 20 paents) served as untreated controls. Daily measurements were made of weight–adjusted urine output (ml/kg), fluid balance (input/output), serum creatinine, blood urea and urinary retinol binding protein (RBP).

Results:

The two groups matched in term of age, time and temperature on cardiopulmonary bypass, number of grafts performed and perioperative haemodynamic status. No differences were detected in the weight-adjusted urine output, fluid balance, serum creatinine and blood urea between the groups. The patients treated with dopamine (Group 1) had much greater urinary excreation of RBP over the same period (1120 ± 10 mg / m.mol Cr and 390 ± 20 mg / m.mol Cr versus 290 ± 5 mg / m.mol Cr and 40 ± 3 mg / m.mol Cr in group 2; p = 0.03) than those in Group 2.

Conclusion:

Dopamine given at renal-dose does not protect renal tubular function in patients with normal heart and kidney functions undergoing coronary surgery. On the contrary, it increases the severity of renal tubular injury during the early postoperative period. We do not recommend the use of dopamine for routine renal prophlaxis in this patients.