The effects of fenoldopam on renal function in patients undergoing elective aortic surgery

Abstract

Background and objective: Postoperative renal impairment is a recognized complication of infrarenal aortic cross-clamping. Our hypothesis was that the renal vasodilating and natriuretic effects of fenoldopam mesylate, a selective dopamine (DA₁) agonist, would preserve renal function in patients undergoing elective infrarenal aortic cross-clamping.

Methods: A prospective, randomized, double blind controlled clinical trial was performed. Twenty-eight ASA II-III patients undergoing elective aortic surgery requiring infrarenal aortic cross-clamping were studied. According to random allocation, patients received either fenoldopam (0.1 μg kg⁻¹ min⁻¹) or placebo intravenously prior to surgical skin incision until release of the aortic clamp. Plasma creatinine, creatinine clearance, urinary output, fractional excretion of sodium, and free water clearance were measured: (a) prior to admission to hospital; (b) during the period from insertion of the urinary catheter until application of the aortic cross-clamp; (c) during the period of aortic cross-clamping; (d) 0-4 h, and (e) 4-8 h after release of the clamp and on days 1, 2, 3, and 5 postoperatively.

Results: Fenoldopam (0.1 μg kg⁻¹ min⁻¹) administration was not associated with haemodynamic instability. On application of the aortic cross-clamp creatinine clearance decreased significantly in the placebo (83 ± 20 to 42 ± 29 mLmin⁻¹ (mean ± SD)) (P < 0.01) but not in the fenoldopam group, and this decrease persisted for at least 8 h after release of the cross-clamp (83 ± 20 to 54 ± 33 mLmin⁻¹ (mean ± SD)) (P < 0.05). Plasma creatinine concentration increased significantly from baseline on the first postoperative day in the placebo group (87 ± 12 to 103 ± 28 μmol L⁻¹ (mean ± SD)) (P < 0.01) but not in the fenoldopam group.

Conclusions: These findings are consistent with the hypothesis that fenoldopam possesses a renoprotective effect during and after infrarenal aortic cross-clamping.