1. Common Terminology Used and Physiology in CRRT Jordan M. Symons, MD University of Washington School of Medicine Seattle Children’s Hospital Seattle, WA - USA 8th International Conference On Paediatric Continuous Renal Replacement Therapy (pCRRT) 16th - 18th July 2015 Queen Elizabeth II Conference Centre, London, UK

2. Continuous Renal Replacement Therapy (CRRT) Extracorporeal circuit similar to IHD Runs continuously Particle removal may be by diffusion, convection or a combination Fluid removal by ultrafiltration Rinse-O-Matic 3000

3. Current Nomenclature for CRRT SCUF:Slow Continuous Ultrafiltration CVVH: Continuous Veno-Venous Hemofiltration CVVHD:Continuous Veno-Venous Hemodialysis CVVHDF: Continuous Veno-Venous Hemodiafiltration

4. C VV H Basis for CRRT Nomenclature Rate/Interval for Therapy Blood Access Method for Solute Removal

5. SCUF CVVH CVVHD CVVHDF UF D R CRRT Schematic

6. Diffusion Small molecules diffuse easily Larger molecules diffuse slowly Dialysate required –Concentration gradient –Faster dialysate flow increases mass transfer

7. Convection Small/large molecules move equally Limit is cut-off size of membrane Higher UF rate yields higher convection but risk of hypotension May need to Replace excess UF volume H2OH2O H2OH2O H2OH2O H2OH2O Net Pressure

8. Effect of Pore Size on Membrane Selectivity Creatinine 113 D Urea 60 D Glucose 180 D Vancomycin ~1,500 D Albumin ~66,000 D IgG ~150,000 D

9. Rate Limitations of Volume Removal Vascular Compartment Extra-Vascular Compartment BP

10. Improved Volume Removal with Slower Ultrafiltration Rates Vascular Compartment Extra-Vascular Compartment BP Stable

11. CRRT for Metabolic Control

12. Solution/Effluent Flow Rate is Limiting Factor in CRRT Q B 150ml/min Q D 600ml/hr Q R 600ml/hr Effluent 1200ml/hr +

13. Solution/Effluent Flow Rate is Limiting Factor in CRRT Q B 150ml/min Q D 1000ml/hr Q R 1000ml/hr Effluent 2000ml/hr +

14. Patient’s Chemical Balance on CRRT Approximates Delivered Fluids Diffusion: blood equilibrates to dialysate Convection: loss is isotonic; volume is “replaced” Consider large volumes for other fluids (IVF, feeds, meds, etc.) Watch for deficits of solutes not in fluids

15. Pediatric CRRT Terminology and Physiology: Summary CRRT comes in several flavors –SCUF, CVVH, CVVHD, CVVHDF Solute transport: diffusion/convection UF approximates 1-compartment model Membrane characteristics affect therapy Fluid composition, rates drive clearance

18. Thank You for Your Attention