Inclusion Criteria:  Patients at least 18 years old and who are undergoing cardiac procedures (coronary artery bypass, valve replacement or combined procedure), with cardiopulmonary by- pass.  Exclusion Criteria:  Congenital heart disease Infective endocarditis Acute myocardial infarction (<two weeks) Pregnancy Cancer Left ventricle ejection fraction < 40% Cardiogenic shock Emergent procedure Use of vasopressor and/or inotrope, in the preoperative Liver disfunction Renal replacement therapy Nephrectomy Previous renal transplantation Patients who are participating in another clinical research