Basics of CRRT: Terminology Theresa Mottes, MSN, RN, CPNP-AC Cincinnati Children’s Hospital Center for Acute Care Nephrology

Standardization of Terminology Patient safety Comparing modalities Common language I want to thank the planning committee for the opportunity to present at this conference. I’m honored to be following in Jordan Symons foot steps in presenting on this topic. Also for sharing his slides as well. The importance of understanding the current terminology, both within your institutions as well as in the literature.

Diffusion or Convection Continuous Renal Replacement Therapy Extracorporeal circuit Continuous in nature Particle removal Diffusion or Convection Fluid removal via ultrafiltration

Nomenclature for CRRT Modalities SCUF Slow Continuous Ultrafiltration CVVH Continuous Veno-Venous Hemofiltration CVVHD Continuous Veno-Venous Hemodialysis CVVHDF Continuous Veno-Venous Hemodiafiltration

Basis for Nomenclature V H Interval Therapy Blood Access Method of Solute Removal

CRRT Schematic SCUF CVVH CVVHD CVVHDF

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 Net Pressure H2O H2O H2O H2O

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

CRRT Dose = Effluent Flow Rate QR 600ml/hr QB 150ml/min QD 600ml/hr Effluent 1200ml/hr +

Effluent Flow Rate is Limiting Factor in CRRT QR 1000ml/hr QB 150ml/min QD 1000ml/hr Effluent 2000ml/hr +

Fluid Removal via CRRT Ultrafiltration Rate = Patient Fluid Removal Rate Movement of fluid (plasma water) by a pressure gradient Net Fluid Balance Even Positive Negative

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

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

CRRT Pressure Related Terms Arterial/Access/Pull/Inlet Blood moving from patient to extracorporeal circuit Venous/Return/Push/Outlet Blood moving from the extracorporeal circuit to the patient

CRRT Pressure Related Terms Transmembrane Pressure Reflects the efficiency of the filter fibers Pressure Drop Reflect the ability of the blood to pass through the membrane fibers

Summary CRRT modalities differ based on solute transport: SCUF, CVVH, CVVHD, CVVHDF Solution rates drive clearance rates Standardize your institutional language Align your language with your machinery

Thank You Questions?