ICU · Renal / RRT

Renal Replacement Therapy Modalities — IHD vs CVVH vs CVVHDF vs SLED

Also known as Renal replacement therapy · RRT · Haemodialysis · IHD · Continuous renal replacement therapy · CRRT · CVVH · CVVHDF · SLED · Diffusion · Convection · Ultrafiltration · Citrate anticoagulation · AEIOU

The renal replacement therapy (RRT) removes the solutes and the fluid when the kidneys fail. The four modalities — the intermittent haemodialysis (IHD), the continuous veno-venous haemofiltration (CVVH), the continuous veno-venous haemodiafiltration (CVVHDF), and the sustained low-efficiency dialysis (SLED) — differ in the solute-transport mechanism (the diffusion vs the convection), the duration and the intermittency, and the haemodynamic tolerance. The IHD is diffusion-based, intermittent, rapid, and for the stable patient (the rapid solute and fluid shifts cause the hypotension and the dialysis disequilibrium). The CVVH is convection-based, continuous, gentle, and for the haemodynamically unstable and the catabolic patient (the middle-molecule clearance). The CVVHDF combines both and is the commonest CRRT modality. The SLED is the hybrid bridge. The indications follow the AEIOU (the Acidosis, the Electrolytes, the Intoxication, the Overload, the Uraemia). The anticoagulation is the regional citrate (preferred) or the heparin. The CRRT dose is 20 to 25 mL/kg/h (the ATN and the RENAL trials — the higher dose offered no benefit). The early vs the late RRT (the AKIKI, the STARRT-AKI, the ELAIN) — no clear benefit of the early in the moderate AKI.

Checked against its sources on 2 Sept 2026