Continuous Renal Replacement Therapy (CRRT) Workshop

Cyrus Custodio, CNC

King Faisal Specialist Hospital & RC

Riyadh, Saudi Arabia

Objectives

• Purpose of CRRT• Advantages of CRRT• Filter dynamics• Transport mechanisms of CRRT• Modes of therapy & indications• Flow rate relationships• Pressures & their meanings• Buffer selection

Outline for the Workshop

1430-1440 Introduction

1440-1500 Review of CRRT

1500-1530 Practical Hands On CRRT Machine CRRT Initiation Sharing of practical experiences in dealing with the CRRT

machine. Troubleshooting Practice

1530-1600 Break & Prayer

1600-1610 Modalities Review (Flash Animation)

1610-1640 Jeopardy

1640-1700 Workshop Summary

CRRT: Important Points to Remember During This Workshop

• Maintaining expertise with a rarely-performed procedure can be difficult.

• Planning ahead (protocols, procedures, etc) helps avoid confusion at the bedside.

• Communication and cooperation is essential.• Do what you do best.

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

• 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

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

Why continuous therapies?

• 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 hemodynamically unstable patient

• Slower solute & fluid removal - IHD removes fluid & solutes more rapidly than CRRT does.

• If the patient has a life-threatening condition hemodialysis may be used initially to correct and stabilize …… then CRRT used to further correct the condition.

• Overtime CRRT demonstrates a superiority by longer periods of RRT.

Advantages

• Hemodynamic stability

• Management of fluid overload

• Control of Urea and creatinine

• Nutritional support

• Membrane absorption and removal of humoral mediators of sepsis

• Effect on mortality ( CRRT vs IHD ) Unclear whether either modality is superior in terms of survival Much larger prospective controlled studies are required Consensus that CRRT can be more safely performed in

hemodynamically unstable patients

Terminology

Hemodialysis• transport process by which a solute passively diffuses down its• concentration gradient from one fluid compartment (either blood

or dialysate) into the other

Hemofiltrattiion• use of a hydrostatic pressure gradient to induce the filtration (or

convection) of plasma water across the membrane of the hemofilter.

Hemodiafiltration• dialysis + filtration.• solute loss primarily occurs by diffusion dialysis but 25 percent

or more may occur by hemofiltration

Who is affected by Acute Renal Failure (ARF)?

• ARF occurs most often in people who are already hospitalized for other medical conditions. • Patients with hospital-acquired ARF are more likely

than those with community-acquired ARF to be admitted to the ICU.

• Up to ~ 70% of intensive or critical care patients develop ARF.

Where is CRRT Performed?

• Practice patterns for CRRT are extremely variable.

• Broadly speaking, CRRT is almost exclusively applied to ICU patients.

• However, beyond this, there are large variations in practice.

Derek Angus, Rinaldo Bellomo & Robert Star, 2000 Selection of patients for acute extracorporeal renal support in general and CRRT in particular Acute Dialysis Quality Initiative Workgroup 2

TRANSPORT MECHANISMSContinuous Renal Replacement Therapy

Transport mechanism: DIFFUSION

Movement of solute from an area of high concentration to an area of low concentration• In the case of dialysis, via a semi permeable membrane• Concentration gradient necessary• Rate of diffusion is dependent on:

surface area of filter ratio of dialysate flow to blood flow size of the solute

• Removes small molecules effectively

Transport mechanism: DIFFUSION

Transport mechanism: ULTRAFILTRATION

Movement of fluid across a pressure gradient.

Positive pressure in blood compartment

Negative pressure in dialysate compartment

Transport mechanism: CONVECTION

• The movement of solutes with a water flow or “Solvent drag”

• Used to remove middle and large molecules

• The greater the amount of fluid that moves, the greater the solute loss

Transport mechanism: CONVECTION

Transport mechanism: ADSORPTION

• Surface adsorption where the molecules are too large to permeate and migrate through the membrane; however can adhere to the membrane.

• Bulk adsorption within the whole membrane when molecules can permeate it.

Transport mechanism: ADSORPTION

Adsorption: molecular adherence to the surface or interior of the membrane.

Molecules that can be effectively adsorbed include:- B2 Microglobulin- Cytokines- Coagulation factors- Anaphylatoxins

It must be noted that movement of fluid is required for adsorption to occur

TREATMENT MODALITIESContinuous Renal Replacement Therapy

Modality: SCUFSlow Continuous Ultrafiltration

PRINCIPLEUltrafiltration

PROCESSUsual blood circuit, synthetic membrane and anticoagulation.Fluid removal occurs due to volume.

APPLICATIONS Fluid overload, acute and chronic patients.

Modality: CVVHContinuous Veno-Venous Hemofiltration

PRINCIPLEHemofiltrattiion Ultrafiltration & Convection.

PROCESSBlood circuit, filter & anticoagulation. Fluid removal and replacement solution.

APPLICATIONSARF/Critically ill patients.

Modality: CVVHDContinuous Veno-Venous Hemodialysis

PRINCIPLEDiffusion and Ultrafiltration

PROCESSBlood circuit, filter and anticoagulation. Dialysate pathway provided by pumps using sterile fluid.

APPLICATIONSEfficient treatment for small molecule clearance (ARF /CRF, critically ill, sepsis.)

Modality: CVVHDFContinuous Veno-Venous Hemodiafiltration

HEMODIAFILTRATION

Hemodialysis and Hemofiltration

PRINCIPLEDiffusion, Convection and Ultrafiltration.Best clearance of small, middle and large molecules.Pre-dilution can decrease clotting.Cost increase

Summary of Modalities

PRINCIPLE SCUF HV & CVVH

CVVHD CVVHDF

Ultrafiltration YES YES YES YES

Convection NO YES NO YES

Diffusion NO NO YES YES

Dialysate NO NO YES YES

Replacement Fluid

NO YES NO YES

What is Removed

FluidFluid & some

Solutes

Fluid & Solutes

Fluid & Solutes

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

50

molecular weight,in Daltons

}

}}

“small”

“middle”

“large”

Program Issues: What is Needed at Your Hospital to Start a CRRRT Program

Disposables/Machine/Equipments

CRRT Equipment: Separate and accurate pumps and scales for each

component of CRRTRange of blood flows with a minimum of

20ml/minThermoregulationMaximum safety features

CRRT Machines: Current Generation

Supplies

CRRT Circuit:• Pediatric :

• Minimum priming volume with low resistance Neonatal lines Pediatric lines

• Exchangeable components• Biocompatible membrane

• Adult• Exchangeable components• Biocompatible membrane

CRRT Competency Management

1. Organize your CRRT competency assessment– Determine critical competencies to evaluate annually – Tie critical competencies to annual performance reviews

2. Understand JCIA expectations– Patient Safety Goals

3. Develop your CRRT competency assessment program– Design a compliant, consistent and effective competency assessment

program 4. Validate CRRT competency

– Validate clinical proficiency5. Maintain a consistent CRRT validation system

– Ensure that clinical proficiency is assessed and validated in a consistent manner with our easy to implement skill sheets

6. Keep up with new CRRT competencies – Verify and document new—and existing—competencies, including those

for new equipment

CRRT Training and Education

• Nurses Critical Care Nephrology

• Physicians: Ongoing

education Grand Rounds,

small groups BECOME AN

ACCEPTED PART OF THE TEAM

• Pharmacists• Nutritionists

CRRT Education Plan Dialysis ICU

History of CRRT

Definition of Acronyms and Terms

The Pediatric Ideal

Concepts related to fluid removal

Concepts related to solute removal

Formulas related to CRRT

Components of a 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

Indications for CRRT in the critical care setting

CRRT outcomes research

12th Annual International Conference on Continuous Renal Replacement Therapy, San Diego, CA, USA.

CRRT Education Plan

Competencies: Bedside ICU Nurse

Verbalize• How CRRT works (fluid and solute

balance, changes in nutrition and medications)

• Reason for treatment• When and how to terminate

treatment• How to troubleshoot alarms (AP,

VP, blood leak, error codes, air detector)

• When and how to recirculate the system

• How to care for catheter and catheter exit site

• When and how to contact nephrologists or hemodialysis nurse

• How to operate extracorporeal circuit warmer

Demonstrate• How to calculate fluid balance• How to assess clotting in the

system• How to adjust AP and VP

limits, BFR, UFR• How to verify dialysis and

replacement fluid solution and rates

• Document continuing care in nursing notes and CRRT flow chart

• Highly skilled in troubleshooting alarms

Competencies:Nephrology Nurse

• Knows how CRRT works

• Reason for treatment• When and how to

terminate treatment• Equipment operation• Most common alarms

conditions• When and how to

reach the nephrology team

• Fluid balance calculations

• Assessment of clotting• How to adjust AP/VP

limits, BFR or UFR• How to verify dialysis

fluid or replacement fluid and/or rate changes

Time Zero

10 20 30 40 50 60 90 120... minutes

Nephrology MD: Contacts HD Nurse to start CRRT

ICU Nurse: Moves Patient to

Room with HD water Port

HD Nurse: Meet MD; discuss RRT Plan

HD Nurse: Arrives at HD Unit and Begins Set-up

ICU Nurse: Meet MD; discuss RRT

Plan

HD Nurse: Completes Prime; Ready for

Access; Meet the ICU Team and starts CRRT

ICU Nurse: Meet ICU Team and Nephrology commences CRRT

Intensivist MD: Arrive & begin insertion of HD Access Intensivist MD: Completes insertion of HD Access

Nephro.MD:

Enters Orders for RRT

Nephrology MD: Meets ICU MD’s and RN’s; Discuss RRT Plan

Nephrology MD: Present in ICU for

initiation; Meet ICU Team

Time Zero

10 20 30 40 50 60 90 120... minutes

Time Zero

10 20 30 40 50 60 90 120... minutes

Acute Initiation Timeline: Example

The Nephrologist in-charge of CRRT must continuously interact and communicate with all the other practitioners involved.

Th e M u l t id isc ipl in a r y a ppr o a c h

Audit

Patient Care: CRRT

Policies & Documents

Standards

Physicians

Pharmacists

Suppliers

Educators

Nurses

Technicians

CRRT “Leader ”

Practical information: Techniques and Methods to Perform CRRT

Practical information: Techniques and Methods to Perform CRRT

Practical Hands On CRRT Machine

• Lines volume and tracing• Pre/post dilution• Set and check orders• Opaque/non-opaque alarm• What mode are we in?• Transducer maintenance• Help key, Graphs, scales,• Bag/syringe Change• Dialysate/substituate bags

preparation• Change post-dilution to

pre.

• Alarms settings (automatic)

• Venous bubble catcher: ↑or ↓ level

• Arterial chamber: ↑or ↓ level

• De-aeration• Blood sampling• Hand bolus Vs Sub bolus• Flushing filters• Temporary Disconnect• Terminate treatment with &

without blood return

CRRT Access : What Works?

Pediatrics• PERMAMENT CATHETER

36 CM 1.3 cc 1.4 cc

40 CM 1.4 cc 1.5 cc

45 CM 1.6 cc 1.7 cc• TEMPORARY CATHETER

24 cm 1.4 ml 1.5 ml (Fr 11.5)

19.5 cm 1.2 ml 1.3 ml (Fr 11.5)

19.5 cm 1.0 ml 1.1 ml (Fr 10)

Adults

Patient Size (kg) Vascular Access

2.5-10 6.5 Fr DLC (10cm)

10-20 8Fr DLC (15cm)

>20 10.8Fr or larger DLC (20cm)

Pediatric Perma Cath 28 Cm 0.8 cc 0.85 cc

Strazdins V, etal. RRT for ARF in Children: European Guidelines

Correct Double Lumen Catheter (DLC) Connection

Re-circulation is particularly high (20-40%) whenever the roles of the different catheter lumens are exchanged (the venous become arterial and vice versa).

CRRT in Pediatrics

Strazdins V, et al. RRT for ARF in Children: European GuidelinesArtificial Organs, 27(9):781-785 Overview of Pediatric RRT in ARFBaldwin, I. et al, Adequacy Dialysis Quality Initiative, 4 th International Consensus Conference

After access insertion, staffing in place, CRRT circuit is blood primed for patients < 15kg

Extracorporeal circuit volume greater than 10% of patients circulating blood volume.Age Estimated Total Blood volume in

ml/kg

Preterm infants

90 -105 ml

Term newborns

78 -86 ml

1-12 months 73 -78 ml

1-3 years 74 -82 ml

4-6 years 80 -86 ml

7-18 years 83 -90 ml

Adults 66 -88 ml

Note: From Gunn, V. L. & Nechgyba, C. (2002)

• The ECBV (blood in the dialyzer and bloodlines) should not exceed 10% of the patient’s total blood volume.

• If the ECBV will exceed 10%, of the patient’s total blood volume it must be primed with blood/human albumin.Formula : Estimated total blood volume by age X body weight X 10%.

Example: Patient is 12 months old with body weight 10kg.: Calculation = (78 ml x 10 x 10 ) = 78 ml 100

CRRT in Pediatrics

• Use a Tru-Flo or PALL blood filter • Blood “chases” the NS out into the priming collection bag. • When blood bag is near empty, stop pump and clamp the arterial

and venous lines.• Disconnect blood and collection bags and quickly proceed to

patient connection.• Enter therapy very slowly ~ 10ml/minute

Advance BFR slowly (15-20 minutes)

Potential Complications of CRRT

• Volume related problems• Biochemical and nutritional problems• Hemorrhage• Infections• Thermic loss • Technical problems• Logistical problems

CRRT Flash Animation (Modes review)

multifiltrate_GB.exe

CRRT WORKSHOPFourth Annual International Conference of Saudi Society of

Nephrology

26-29 April 2009

Riyadh, Saudi Arabia

Summary

• CRRT is something we can do• Can be life-saving for critically ill patients (pediatric and

adult)• Careful planning of the institution’s program, standardized

protocols and orders and continuous education of Health Care Providers improves care.

• Technical challenges can be met.• Cooperation, Communication (KEY) and Collaboration

will increase our success!

12th Annual International Conference on Continuous Renal Replacement Therapy, San Diego, CA, USA.