Renal Replacement Therapy


Fundamentals of Dialysis and Ultrafiltration

Figure 1: Diffusion across a semi-permeable membrane

Figure 2: Convection

Figure 3: Adsorption to the Membrane

Figure 4: Membrane Selectivity Based On Molecular Size

Figure 5: Clearance Based On Molecular Size

Peritoneal Dialysis (PD)

Intermittent Hemodialysis (iHD)

Continuous Renal Replacement Therapy (CRRT)



1) SCUF: Slow Continuous Ultrafiltration: Basically, take blood out from the patient, pass it through a semipermeable membrane at pressure, leading to fluid removal (ultrafiltration) with some solute loss as a result of convection. No dialysate solution or replacement fluid is used.

Figure 6: SCUF 

2) CVVH: Continuous Veno-venous hemofiltration: Utilizes convection but no dialysate fluid so no diffusion

3)CVVHD: Continuous Veno-venous hemodialysis: Utlizes dialysate fluid/counter current exchange but no pre/post replacement fluids to generate convection (hence no significant clearance of larger molecules like cytokines)

4) CVVHDF: Continuous veno-venous hemodiafiltration: Utilizes convection (ie can clear larger molecules like cytokines) as well as a dialysate fluid to produce diffusion

CRRT Basics Workbook (Baxter)

Figure 7: CVVHDF

Anticoagulation for CRRT

General Dosing Guidelines


Filter Sets:

Initiation Procedures:

Figure 8: Citrate and Calcium Titration Guidelines

Special Considerations for CRRT

Additional Reading


1) Tobe SW, Aujla P, Walele AA, Oliver MJ, Naimark DM, Perkins NS, Beardsall M: A novel regional citrate anticoagulation protocol for CRRT using only commercially available solutions. J Crit Care 18: 121–129, 2003

2) S. Walters, C. Porter, P.D. Brophy: Dialysis and pediatric acute kidney injury: choice of renal support modality.Pediatr Nephrol. 24:37-48 2009

3) J.A. Foland, J.D. Fortenberry, B.L. Warshaw, et al.: Fluid overload before continuous hemofiltration and survival in critically ill children: a retrospective analysis. Crit Care Med. 32:1771-1776 2004

4) S.L. Goldstein, H. Currier, C. Graf, et al.: Outcome in children receiving continuous venovenous hemofiltration. Pediatrics. 107:1309-1312 2001

5) Dr. Kera Lucritz's CRRT Fellow Presentation

6) NEJM Review Article on CRRT

7) TPE/Pheresis Overview