Pediatric CRRT Terminology

Helen Currier BSN, RN, CNNAssistant Director, Renal/Pheresis

Texas Children’s Hospital

Houston, Texas

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

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)

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

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– Arteriovenous– Venovenous

Other factors– Hematocrit– Plasma proteins– Transmembrane pressure

Basic Concepts of CRRT: Concepts Related to Solute Removal or Clearance

Convection – solute drag; hemofiltration

Diffusion – concentration gradient; hemodiafiltration

Solute Mass Transfer in CRRT

Post-Dilution CVVH CVVHD

Pre-Dilution CVVH CVVHDF

Qb

Qb Qb

Qb

Qeff Qeff

QeffQeff Qd

Qd

Qr

Qr

Qr

Solute Molecular Weight and ClearanceSolute (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)

0

5

10

15

20

25

30

CVVH CVVHD

U

rea

Cle

aran

ce(m

ls/m

in/1

.73

m2)

BFR = 4 mls/kg/minFRF/Dx FR = 2 l/1.73 m2/hrSAM = 0.3 m2

p = NS

Methods of Continuous Renal Replacement Therapy

Definition of Acronyms and Terms

SCUF slow continuous ultrafiltration CAVHCAVH continuous arteriovenous continuous arteriovenous

hemofiltrationhemofiltration CAVHDCAVHD continuous arteriovenous continuous arteriovenous

hemodialysishemodialysis 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

The Pediatric Ideal: CRRT Circuit

Minimum priming volume with low resistance

Exchangeable components

Biocompatible membrane