Physiologic impact of low-dose dopamine on renal function in the early post renal transplant period.

Background: Low-dose dopamine (LDD) (< or =5.0 microg/kg/min) is often used in the early postrenal transplant period for its perceived improvements in renal function parameters. However, there is little published evidence to support its use. The aim of this study was to evaluate the effects of LDD on the physiologic parameters of the transplanted kidney.

Methods: With local ethics approval, 20 consecutive adult patients (age range, 27-74 years), who underwent cadaveric renal transplantation with cyclosporine immunosuppression, were randomized into two study groups, each with 10 patients. The study period was over 9 hrs on the first postoperative day. This 9-hr block was divided into three 3-hr periods. Patient group 1 received a dopamine infusion over the second 3-hr period only, and patient group 2 received a dopamine infusion over both the first and third 3-hr periods. During these periods, urine flow rate (UFR), effective renal plasma flow (ERPF), creatinine clearance (CC), and total urinary sodium excretion rate (tUNa) were measured.

Results: In both groups, there were significant (P<0.05, Wilcoxon rank sum test) increases in ERPF, UFR, CC, and tUNa during LDD infusion periods compared with periods of no LDD infusion. No changes in heart rate or mean arterial blood pressure were seen with LDD administration.

Conclusions: LDD significantly increases ERPF, UFR, CC, and tUNa in the transplanted allograft kidney treated with cyclosporine immunosuppression in the early posttransplant period.