The renal haematic flow decrease, the vasoconstriction and the local vascular resistance increase, associated with descending aortic cross-clamping, before the origin of renal arteries, can be contrasted by continuous infusion of fenoldopam, a dopamine analog with selective action on DA1-receptors. The renal effects of this molecule are renal plasmatic flow increase and local vascular resistance decrease, without important haemodynamic changes, with mild cardiovascular modification, even at high doses, in hypertensive and non hypertensive patients, also in normal volume condition and hypovolemic condition. This selective action at renal level allows the use of fenoldopam also in surgical emergencies, in patients with low cardiovascular function. The case report here presented demonstrated a beneficial renal effects of continuous infusion of fenoldopam and its easy to use, in emergency situations. These findings could be extrapolated for other patients or suggested for additional research.