Inclusion Criteria:  Patients older than 18 years old. Patients with CKD that attends to the outpatient clinic. Residual uresis of 500 mL  Exclusion Criteria:  Patients younger than 18 years old. Increase of Cr in a rate of 0.5 mg/dL, or loss of more than 30% of previous GFR. Patients with cardiorrenal syndrome type 1. Patients with dilated miocardiopathy. Volume overload.