CRRT basic principal by Wael Nasri

1© Copyright L.Burchell, Gambro 2003

ContinuousRenalReplacementTherapy


CRRT = CONTINUOUS RENAL REPLACEMENT THERAPY

Defined as

– “Any extracorporeal blood purification therapy intended to

substitute for impaired renal function over an extended period

of time and applied for

or aimed at being applied for 24 hours /day.” *

* Bellomo R., Ronco C., Mehta R, Nomenclature for Continuous Renal

Replacement Therapies, AJKD, Vol 28, No. 5, Suppl 3, November 1996


Evolution of

CRRT

CAVHD

BSM - VPM

PRISMA

2nd Generation

extracorporeal

blood purification

system


History of CRRT

1950’s - CRRT concept originated

1960’s - Scribner proposed CAVHD in context of ARF

1977 - Kramer introduces CAVH

1980 - Paganini introduces SCUF

1984 - Geronemus and Schneider propose CAVHD


History of CRRT, cont’d.

1987 - Uldall introduces CVVHD

1990’s - Transition to VV therapies from AV therapies

1996 - R. Mehta, UCSD, hosts the first international conference on CRRT in San Diego


REVIEW OF BASICS…






Molecular Weights

• Albumin (55,000 - 60,000)

• Beta 2 Microglobulin (11,800)

• Inulin (5,200)

• Vitamin B12 (1,355)

• Aluminum/Desferoxamine Complex (700)

• Glucose (180)• Uric Acid (168)• Creatinine (113)• Phosphate (80)

• Urea (60)

• Phosphorus (31)• Sodium (23)

• Potassium (35)

100,000

50,000

10,000

5,000

1,000

500

100

50

10

5

0

molecular weight,

daltons

}

}}

“small”

“middle”

“large”


RIFLE Criteria


INDICATIONS FOR CHOOSING Continuous Renal Replacement Therapy


Clinical Indications for CRRT

Renal Indications

• Azotemia

• Fluid Overload

• Tumor lysis Syndrome

• Sepsis

• Cerebral edema

Non-renal Indications

• Metabolic Disorders

• Fluid Overload

• CPB, IABP, ECMO

• Sepsis

• ARDS

• Crush injuries

• CHF


INDICATIONS FOR CHOOSING

Continuous Renal Replacement Therapy

Cardiovascular instability

Ongoing acidosis

Large obligatory fluid intake

Increased catabolism

Increased intracranial pressure

Sepsis ?


Introduction to CRRT

• Continuous therapies closely mimic the native kidney in treating ARF and fluid overload

• Slow, gentle and well tolerated by hypotensive patients

• Remove large amounts of fluid and waste products over time

• Tolerated well by the hemodynamicallyunstable patient.

Why continuous therapies?


What are we trying to achieve?

Waste removal

Electrolyte balance

Fluid balance

Acid-Base balance

Removal of septic mediators


Advantages

Hemodynamic stability

Management of fluid overload

Control of Urea and creatinine

Nutritional support

Membrane absorption and removal of humoral mediators of sepsis


Principles of CRRT clearance

CRRT clearance of solute is dependent on the following:

• The molecule size of the solute

• The pore size of the semi-permeable membrane

The higher the ultrafiltration rate (UFR), the greater the solute clearance.


Replacement Fluids

Physician Rx and adjusted based on pt. clinical need.

Sterile replacement solutions may be:

• Bicarbonate-based or Lactate-based solutions

• Electrolyte solutions

• Must be sterile and labeled for IV Use

• Higher rates increase convective clearances

• You are what you replace


Continuous Renal Replacement Therapy

SCUF Slow Continuous Ultra-Filtration

CVVH Continuous Veno-Venous Hemofiltration

CVVHD Continuous Veno-Venous Hemodialysis

CVVHDF Continuous Veno-Venous Hemodiafiltration


Renal Recovery?

CRRT does affect resumption of function.


By avoiding hypotensiveepisodes, the risk of further kidney damage is reduced and the chance for renal recovery is enhanced


30610

0135

0

.2

.4

.6

.8

1

0 20 40 60 80 100

IRRT

CRRT

days

Recovery from Dialysis Dependence: BEST Kidney DataR

ecovery

fro

m d

ialy

sis

dependence

Manuscript under review

Leading the way…


CRRT vs. IHD in Renal Recovery

Recent studies suggest that CRRT is superior to IHD with respect to recovery of renal function

Implications go far beyond just “hard” endpoint of renal recovery

• Need for chronic dialysis impairs quality of life

• If length of stay (LOS) in ICU can be reduced this will have a major impact on hospital budget

• Patients dependent on chronic dialysis will consume significant health care resources and have an impact on the community health care budget


Access Location

Internal Jugular Vein

• Primary site of choice due to lower associated risk of complication and simplicity of catheter insertion.

Femoral Vein

• Patient immobilized, the femoral vein is optimal and constitutes the easiest site for insertion.

Subclavin Vein

• The least preferred site given its higher risk of pneumo/hemothorax and its association with central venous stenosis


Advanced therapy

• Therrapeuticplasma exchang

TPE• HemoperfusionHP


THANK YOU

Health & Medicine

CRRT basic principal by Wael Nasri