1 prismaflex crrt intro - seg 1 (2007)

PrismaFlex STEPP

Basic CRRT Principles

®

Course ObjectivesBy the end of the Gambro CRRT training course

the participant will be able to:

• Define CRRT and the associated therapies

• Discuss the basic CRRT principles

• Discuss the basic principles of the solute transport mechanisms

• Identify the clinical indications for administering CRRT, including

an overview of patient selection and therapy application

• Have a working knowledge of basic CRRT machine set up, run, end

treatment and troubleshooting skills.

• Describe the CRRT machine’s safety management features,

pressure monitoring and fluid balance principles.

Continuous Renal Replacement Therapy (CRRT)

““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, Nov 1996

CRRT closely mimics the native kidney in treating ARF and fluid overload

Why CRRT?

Removes large amounts of fluid and waste products over time

Tolerated well by hemodynamically unstable patients

CRRT Treatment Goals

Maintain fluid, electrolyte, acid/base balance

Prevent further damage to kidney tissue

Promote healing and total renal recovery

Allow other supportive measures; nutritional

support

Determinants of Outcome

Initiation of Therapy• Ronco Study• Gettings Study• ADQI Consensus Initiative - Rifle Criteria

Dose• Ronco Study• Kellum Meta-Analysis• Saudan Study

Risk

Injury

Failure

Loss

ESRD

GFR Criteria Urine Output Criteria

Increased creatinine x 1.5 or GFR decrease >25% UO <,0.5ml/kg/hr x 6 hours

Increased creatinine x 2 or GFR decrease >50%

UO <0.5 ml/kg/hr x 12 hours

Increased creatinine x 3 or GFR decrease >75% or

Serum Creatinine > 4mg/dlUO <0.3 ml/kg/hr x 24 hours

or anuria x 12 hours

Persistent ARF= complete loss of renal function >4 weeks

End-stage renal disease (>3 months)

EarlyInitiation

Summary Evidenced Based Research reports that

patient survival is improved by:

•Early initiation: •Utilization of RIFLE Criteria

•Minimum dose delivery of 35 ml/kg/hr • eg. 70 kg patient = 2450 ml/h

Effects of different doses in CVVH on outcomes of ARF – C. Ronco M.D., R. Bellomo M.D. Lancet 2000; 356:26-30.

Anatomy of a Hemofilter

• 4 External ports • blood and dialysis fluid

• Potting material • support structure

• Hollow fibers • Semi-permeable

membrane

• Outer casing

CRRT Transport Mechanisms

Molecular Transport Mechanisms

Ultrafiltration

Diffusion

Convection

Adsorption

Fluid Transport

Solute Transport}

Ultrafiltration

•Movement of fluid through a semi-permeable membrane caused by a pressure gradient

•Positive, negative and osmotic pressure from non-permeable solutes

Blood Out

Blood Into waste

(to patient)

(From patient)

HIGH PRESSLOW PRESS

Fluid VolumeReduction

Ultrafiltration

Molecular WeightsDaltons

• Inflammatory Mediators (1,200-40,000)

“small”

“middle”

“large”

Diffusion

•Movement of solutes from an area of higher concentration to an area of lower concentration.

•Dialysate is used to create a concentration gradient across a semi-permeable membrane.

Hemodialysis: Diffusion

Dialysate In

Dialysate Out(to waste)

Blood Out

Blood In

(to patient)

(from patient)

HIGH CONCLOW CONC

Convection

•Movement of solutes with water flow, “solvent drag”.

•The more fluid moved through a semi-permeable membrane, the more solutes that are removed.

•Replacement Fluid is used to create convection

to waste

HIGH PRESSLOW PRESS

Repl.Repl.SolutionSolution

Hemofiltration: Convection

Blood Out

Blood In

(to patient)

(from patient)

Electrolytes & pH Balance

Another primary goal for CRRT, specifically:• Sodium• Potassium• Calcium• Glucose• Phosphate• Bicarbonate or lactate buffer

Dialysate and replacement solutions are used in CRRT to attain this goal.

Adsorption

Molecular adherence to the surface or interior of the membrane.

0

20

40

60

80

100

Cle

aran

ce in

%

35.000 55.00020.0005.0002.500Urea(60)

Albumin(66.000)

Myoglobin(17.000)

65.000Creatinine

(113)

Kidney

Convection

Diffusion

Small vs. Large Molecules Clearance

What is the transport mechanism associated

with dialysate and replacement solutions?

Effluent

Pre Blood Pump Replacement: Convection

Blood

Flow Control Unit – Pumps

Dialysate: Diffusion

Effluent Flow Rate

Effluent = Total Fluid Volume:

•Patient Fluid Removal•Dialysate Flow•Replacement Flow•Pre-Blood Pump Flow

CRRT Modes of Therapy

SCUF - Slow Continuous Ultrafiltration

CVVH - Continuous Veno-Venous Hemofiltration

CVVHD - Continuous Veno-Venous HemoDialysis

CVVHDF - Continuous Veno-Venous HemoDiaFiltration

SCUFSlow Continuous UltraFiltration

Primary therapeutic goal:•Safe and effective management of

fluid removal from the patient

SCUFSlow Continuous UltraFiltration

EffluentPump

Infusion or Anticoagul

ant

Blood Pump

PBPPump

Effluent

Access

Return

CVVHDContinuous VV HemoDialysis

Primary therapeutic goal:• Small solute removal by diffusion• Safe fluid volume management

Dialysate volume automatically removed through the Effluent pump

Solute removal determined by Dialysate Flow Rate.

CVVHDContinuous VV HemoDialysis

Hemofilter

EffluentPump

Effluent

Access

Return

DialysatePump

Dialysate

Fluid

Blood Pump

Infusion or Anticoagul

ant

PBPPump

Dialysate Solutions

• Flows counter-current to blood flow

• Remains separated by a semi-permeable membrane

• Drives diffusive transport • dependent on concentration gradient and flow rate

• Facilitates removal of small solutes

• Physician prescribed

• Contains physiologic electrolyte levels

• Components adjusted to meet patient needs

CVVH: Continuous VV Hemofiltration

Primary Therapeutic Goal: • Removal of small, middle and large sized solutes • Safe fluid volume management

• Replacement solution is infused into blood compartment pre or post filter• Drives convective transport• Replacement fluid volume automatically removed

by effluent pump

Solute removal determined by Replacement Flow Rate.

CVVHContinuous VV Hemofiltration

EffluentPump

Blood Pump

Effluent

Access

Return

ReplacementPump 1

Replacement

Pump 2

Replacement 1

Replacement 2

Infusion or Anticoagul

ant

PBPPump

Pre-Dilution Replacement Solution

•Decreases risk of clotting

•Higher UF capabilities

•Decreases Hct. In filter

Hemofilter

EffluentPump

Blood Pump

PBPPump

Effluent

Access

Return

ReplacementPump

Replacement

Fluid

Infusion or Anticoagul

ant

Post-Dilution Replacement Solution

•Consider lowering replacement rates (filtration %)

•Higher BFR (filtration %)

•Higher anticoagulation

•More efficient clearance (>15%)

Hemofilter

EffluentPump

Blood Pump

Effluent

Access

Return

ReplacementPump

Replacement

Fluid

ReplacementPump

Replacement

Fluid

PBPPump

Infusion or Anticoagul

ant

Replacement Solutions

• Infused directly into the blood at points along the blood pathway

• Drives convective transport• Facilitates the removal of small middle and

large solutes• Physician Prescribed • Contains electrolytes at physiological levels • Components adjusted to meet patient needs

CVVHDFPrimary therapeutic goal:

• Solute removal by diffusion and convection• Safe fluid volume management• Efficient removal of small, middle and large

molecules

Replacement and dialysate fluid volume automatically removed by effluent pump

Solute removal determined by Replacement + Dialysate Flow Rates.

CVVHDFContinuous VV HemoDiaFiltration

EffluentPump

Effluent

Access

Return

DialysatePump

Dialysate

Fluid

Blood Pump

ReplacementPump

Replacement

Fluid

PBPPump

Infusion or Anticoagul

ant