In patients requiring renal replacement therapy (RRT) in the intensive care unit (ICU), continuous techniques are predominantly using due to better hemodynamic tolerance. The most employed techniques in ICU are continuous venovenous hemodiafiltration (CVVHDF) and continuous venovenous hemodialysis (CVVHD).

To our knowledge, there are no prospective studies comparing the efficiency of these two techniques with the same dose of dialysis (and the same filter).

In the CompEER study, we aim to compare the efficiency of CVVHD and CVVHDF on urea reduction rate in intensive care patients with acute kidney injury.

The research hypothesis is that CVVHD citrate technique is as effective as CVVHDF heparin technique for urea reduction and provides prolonged and stable clearance, facilitating antibiotic management during RRT.

Acute Kidney Injury (AKI) is found in more than 50% of intensive care unit (ICU) patients, with 30% classified as AKI Network (AKIN) stage 3. Approximately 23% of AKI patients undergo RRT, predominantly utilizing continuous techniques due to better hemodynamic tolerance in unstable patients. Common continuous RRT techniques include continuous venovenous hemofiltration (CVVH), continuous venovenous hemodialysis (CVVHD), and continuous venovenous hemodiafiltration (CVVHDF).

The two most employed techniques in ICU are CVVHDF and CVVHD. However, the choice often depends on institutional practices rather than scientific evidence. Limited studies comparing these techniques at equivalent doses exist, and French recommendations allow intensivists discretion based on availability and team experience. A small, randomized study comparing different exchange rates found higher urea reduction in CVVHDF but lacked statistical significance. Current practices in ICU involve using CVVHDF with systemic anticoagulation or CVVHD with regional citrate anticoagulation based on practitioner preferences.

Despite potential benefits of CVVHD with citrate, such as extended filter lifespan and stable dialysis dose, the impact on concomitant treatments, especially antibiotics, needs consideration.

The study aims to demonstrate the non-inferiority of citrate-based continuous hemodialysis (CVVHD) compared to heparin-based continuous hemodiafiltration (CVVHDF) in terms of urea reduction rate at 24 hours in AKI patients requiring renal replacement therapy.

The hypothesis is that CVVHD citrate is as effective as CVVHDF heparin, providing prolonged and stable clearance, facilitating antibiotic management during RRT.

Inclusion criteria:

• Adult patients hospitalized in ICU

• Undergo RRT session because of AKI stage 3

• At least one among criteria: pH < 7,20 / Blood urea > 30mM / Fluid overload uncontrolled by with PaCO₂ < 35 mmHg or mixed acidosis with PaCO₂ < 50 mmHg.

  • Oliguria lasting 72 hours or longer

• Patients undergoing their first session of extracorporeal blood purification, initiated less than 12 hours prior to randomization

• Patient having given free and informed consent, and having signed the consent form or patient included in an emergency situation

• Patient affiliated with Social Security.

Exclusion criteria:

• End-stage chronic kidney disease on dialysis
• Intoxication with a dialyzable toxin (lithium
• Criteria for emergency dialysis initiation: hyperkaliemia >6,5mM with electrocardiographic signs
• Medical contraindication to regional citrate: severe liver failure
• Medical contraindication to anticoagulation or heparin anticoagulation: heparin induced thrombopenia or uncontrolled bleeding
• Pregnant women, parturient or breast-feeding patient