Prospective, randomized, blinded study-dividing patients into one of two groups: fenoldopam or placebo. The infusion will commence after placing the patient in a lateral/flex position during the operation. The infusion will continue for a total of 24 hours.Study time period will be approximately six weeks from the date of surgery. Specifically, the following pre- and post operative laboratory results will be recorded if available: . Basic metabolic panel - pre-op, post op days 1, 2, 3, 4, and 6 weeks
* Serum osmolality, urine osmolality, urine sodium - pre-op, post op days 1, 3
* Glomerular filtration rate - pre-op, post op days 1, 3, and 6 weeks
