PCRRT Tûr'mə-nŏl'ə-jē

Helen Currier BSN, RN, CNNAssistant Director, Renal/PheresisTexas Children’s HospitalHouston, 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)

1998 SLEDD introduced as an alternative to CRRT

2000 Continued development of integrated blood pump and fluid balance equipment for CRRT

2002 2nd International pCRRT meeting in Orlando, FL

2004 3rd International pCRRT meeting in Orlando, FL

History of Continuous Renal Replacement Therapy (CRRT)

2006 4th International pCRRT meeting in Zurich, Switzerland

2008 5th International pCRRT meeting in Orlando, FL

2010 6th International pCRRT meeting in Rome, Italy

Bunchman Brophy Goldstein Symons Somers

The Founding Five

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

Convection

High pressure to low pressure across a membrane

Pressure gradient

Solute dissolved in solvent = solvent drag

Bulk-flow of solute across a semi-permeable membrane together with a solvent in a manner that is dependent on transmembrane pressure and membrane characteristics.

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

Convection – solute drag; hemofiltration

Diffusion – concentration gradient; hemodiafiltration

Diffusion

Describes solute transport across a semi-permeable membrane generated by a concentration gradient.

Hemodiafiltration (HDF)

A technique associated with high ultrafiltration rates and diffusion across a highly permeable membrane. Blood and dialysate are circulated as in hemodialysis, but in addition, ultrafiltration, in excess of the scheduled weight loss, is provided. Replacement fluid is used to achieve fluid balance.http://www.usa-gambro.com/upload/Site_us/Patient%Resources/IC/cvvhdf.gif

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

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

Definition of Acronyms and Terms

SLEDD slow low efficient daily dialysis or sustained

low- efficiency daily dialysis

Intermittent therapies

Are those usually prescribed for a period of 12 hours or less.

Extended Daily Dialysis (EDD)

Slow Low Efficiency Dialysis (SLED)

EDD+SLED=SLEDD

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?

Dialysate

A solution of variable composition designed to facilitate diffusion of solutes into the ultrafiltrate-dialysate compartment of the hemofilter or hemodialyzer.http://www.shodor.org/master/biomed/physio/dialysis/hemodialysis/sixa.htm#hollowfiber

Peritoneal Dialysis

An intracorporeal therapy where solute and water are transported across the peritoneal membrane based on osmotic and concentration gradients.

Hemodialysis

An extracorporeal, primarily diffusive therapy, where solute and water are transported across a semi-permeable membrane into dialysate.

High flux

A dialysis membrane designed to provide high water permeability, thereby increasing solute clearance especially large solute such as beta-2 microglobulin.

Transmembrane Pressure

The hydrostatic pressure gradient across the membrane. This is the driving force that causes ultrafiltration.

The Pediatric Ideal: CRRT Circuit

Minimum priming volume with low resistance

Exchangeable components

Biocompatible membrane

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 Equipment

Comes with a expert nurse!