Cardiopulmonary bypass (CPB) for cardiac operations may be accompanied by different patterns of visceral underperfusion. This could result in clinical patterns of lactic acidosis but in the most severe cases there is the risk for mesenteric infarction (0.2% of the cases). Renal function as well may be impaired due to a low oxygen delivery, and acute renal failure occurs in 1-2% of cases.

Fenoldopam mesilate is a selective splanchnic vasodilator when used at a dose < 0.1 mcg/kg/min.

The experimental hypothesis of this randomized, controlled trial (RCT) is that the use of fenoldopam may determine a better visceral perfusion during CPB.

Randomized placebo-controlled double blinded study. Patients undergoing complex cardiac operations will be randomly allocated to the study or the control group.

All the patients will receive the standard of care of our Institution. Adequacy of CPB perfusion will be assessed using oxygen delivery calculation, lactate production, SvO2.

Inclusion Criteria:

• Complex, combined cardiac operation
• Predicted CPB duration > 90 minutes

Exclusion Criteria:

• Age < 18 years
• No written informed consent