Introduction: Chronic kidney disease is characterized by a progressive deterioration of renal function. At the end of the progression, when complications occur (overhydration, electrolyte imbalances or retention of uremic toxins), a percentage of patients requiring renal replacement therapy (haemodialysis). When starting the haemodialysis, the patient holds the residual renal function (RRF) which is lost over time. To preserve the RRF, the patient is treated with diuretics loops and / or thiazide diuretics. The effect of this treatment is lost when renal function worsens. In this context, there are few studies that explore the use and effectiveness of diuretics in patients on haemodialysis 2. Objectives and Hypothesis: