After obtaining written informed consent and inclusion, patients will be randomised into 2 groups for the type of dialysis catheter lock:

• The first group will have a citrate lock
• The second group will have a heparin lock Patients will be stratified according to the centre and type of Renal Replacement Therapy (RRT) continuous or intermittent.

The daily surveillance of patients will not be different from the usual surveillance of patients on Renal Replacement Therapy.

The hemodialysis catheters used will be specific Renal Replacement Therapy catheters.

The decision to withdraw the catheter will be made by the investigator and based on clinical criteria (complications related to the catheter, termination of Renal Replacement Therapy…)

Inclusion Criteria:

• Patients aged > 18 years
• Requiring RRT for acute renal insufficiency
• For which a 1st non-tunneled catheter is placed
• In the jugular or femoral position
• After written informed consent has been obtained from the patient, a member of the family or a person of trust

Exclusion Criteria:

• Patient presenting active poorly controlled bleeding
• Known allergy to citrate
• Acute liver failure (Prothrombin level <30%)
• Thrombopenia < 30 000/mm3
• Known or suspected heparin-induced thrombopenia
• Known systemic bacterial infection at the time the catheter is placed
• catheter in the subclavicular position
• Persons not affiliated to a national health insurance scheme
• Pregnant women
• Adults under guardianship