Pediatric CRRT Terminology Helen Currier BSN, RN, CNN Assistant Director, Renal/Pheresis Texas Children’s Hospital Houston, Texas Concepts related to solute removal Convection Diffusion Formulas related to CRRT Sieving coefficient for a solute Ultrafiltrate concentration/plasma concentration Convective clearance (UFR x UF concentration)/arterial concentration Diffusive clearance (DFR x UF concentration)/arterial concentration Fluid replacement rate and net hourly fluid loss Components of a CRRT System Vascular accesses Blood lines Hemofilters Fluid-integrated CRRT systems Priming the CRRT system Anticoagulation of the CRRT system CRRT Procedures Procedures related to initiation of therapy Procedures related to monitoring therapy Procedures related to terminating therapy Potential problems encountered during CRRT Patient related concerns Dehydration Hypotension Electrolyte imbalance Acid/base imbalance Blood loss Air embolism Technical or procedure-related problems Small size of the patient Establishing vascular access Preventing heat loss Small size of pediatric hemofilters can prohibit the rate of replacement fluids in volumes used in adults Large size of extracorporeal priming volume Clotted hemofilter Poor ultrafiltration rate Blood leaks Malfunction of equipment Indications for CRRT in the critical care setting Fluid removal Patients w/acute renal failure (ARF) Patients w/cardiac instability and severe fluid overload Patients w/burns Patients w/rhabdomyolysis Solute removal Patients w/ARF or liver failure Patients w/inborn errors of metabolism (i.e. hyperammonemia) Patients w/toxic ingestions Patients w/pulmonary failure requiring extracorporeal membrane oxygenation (ECMO) CRRT outcomes research

History of Continuous Renal Replacement Therapy (CRRT) 1960 Continuous arteriovenous approach first described for treatment of renal failure 1974 Ultrafiltration isolated from hemodialysis circuit and the addition of a hemofilter 1975 Hemofiltration technique proposed 1979-82 SCUF and CAVH used by Paganini (MD) and Whitman (RN) at Cleveland Clinic 1960 – Belding Scribner first described a continuous arteriovenous approach for treatment of renal failure 1974 – Silversteins used a technique to perform ultrafiltration isolated from hemodialysis circuit and the addition of a hemofilter 1975 – Henderson proposed hemofiltration technique by collecting an ultrafiltrate of plasma and then reconstituting the blood volume with a fluid composition similar to normal plasma

History of Continuous Renal Replacement Therapy (CRRT) 1980s CRRT used in pediatrics 1987 Pump-assisted CRRT introduced 1990 CRRT considered state of the art therapy for treatment of acute renal failure 1993 Standards of Clinical Practice for CRRT published by the American Nephrology Nurses’ Association (ANNA) and endorsed by the American Association of Critical Care Nurses (AACN) Mid 1980s – CRRT used in pediatrics

History of Continuous Renal Replacement Therapy (CRRT) 2000 Continued development of integrated blood pump and fluid balance equipment for CRRT 2002 Second pCRRT meeting in Orlando, FL 2004 Third pCRRT meeting in Orlando, FL Mid 1980s – CRRT used in pediatrics

Test your knowledge Pediatric CRRT therapies are approximately A. 40 years old B. 30 years old C. 20 years old D. 10 years old

Test your knowledge Pediatric CRRT therapies are approximately A. 40 years old B. 30 years old C. 20 years old D. 10 years old

Indications for CRRT in the Critical Care Setting Fluid removal Solute removal

Basic Concepts of CRRT: Concepts Related to Fluid Removal or Ultrafiltration Blood flow Arteriovenous Venovenous Hydrostatic pressure Other factors Hematocrit Plasma proteins Transmembrane pressure Ultrafiltration or fluid removal – removal of plasma volume across membrane driven by hydrostatic pressure

Basic Concepts of CRRT: Concepts Related to Solute Removal or Clearance Convection – solute drag; hemofiltration Diffusion – concentration gradient; hemodiafiltration Dialysis or clearance – removal of solute across a membrane driven by diffusion and convention

Solute Mass Transfer in CRRT Post-Dilution CVVH CVVHD Pre-Dilution CVVH CVVHDF Qb Qeff Qd Qr

Solute Molecular Weight and Clearance Solute (MW) Sieving Coefficient Diffusion Coefficient Urea (60) 1.01 ± 0.05 1.01 ± 0.07 Creatinine (113) 1.00 ± 0.09 1.01 ± 0.06 Uric Acid (168) 1.01 ± 0.04 0.97 ± 0.04* Vancomycin (1448) 0.84 ± 0.10 0.74 ± 0.04** *P<0.05 vs sieving coefficient **P<0.01 vs sieving coefficient

Comparison of Urea Clearance: CVVH vs CVVHD (Maxvold et al, Crit Care med. 2000 Apr;28(4):1161-5) Study design Fixed blood flow rate - 4 ml/kg/min HF-400 (0.3 m2 polysulfone) Cross over for 24 hrs each to pre-filter replacement fluid (CVVH) or Dx (CVVHD) flow at 2000 ml/hr/1.73 m2

Comparison of Urea Clearance: CVVH vs CVVHD (Maxvold et al, Crit Care med. 2000 Apr;28(4):1161-5) p = NS (mls/min/1.73 m2) Urea Clearance BFR = 4 mls/kg/min FRF/Dx FR = 2 l/1.73 m2/hr SAM = 0.3 m2

Methods of Continuous Renal Replacement Therapy

Definition of Acronyms and Terms SCUF slow continuous ultrafiltration CAVH continuous arteriovenous hemofiltration CAVHD continuous arteriovenous hemodialysis CVVH continuous venovenous hemofiltration CVVHD continuous venovenous hemodialysis CVVHDF continuous venovenous hemodiafiltration

Continuous Renal Replacement Therapy Advantages Slower blood flows Slower UF rates Adjust UF rates with hourly patient intake Increased cytokine (bad humors) removal? Disadvantages Prolonged anticoagulation Increased cytokine (good humors) removal?

The Pediatric Ideal: CRRT Equipment Separate and accurate pumps and scales for each component of CRRT Range of blood flows with a minimum of 20ml/min Thermoregulation Maximum safety features Separate and accurate pumps and scales for each component of CRRT (i.e., UF, replacement fluid, dialysate)

The Pediatric Ideal: CRRT Circuit Minimum priming volume with low resistance Exchangeable components Biocompatible membrane