1. Continuous Renal Replacement Therapy (CRRT) Workshop
Cyrus Custodio, CNC
King Faisal Specialist Hospital & RC
Riyadh, Saudi Arabia

2. 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

3. Outline for the Workshop
Introduction
Review of CRRT
Practical Hands On CRRT Machine
CRRT Initiation
Sharing of practical experiences in dealing with the CRRT machine.
Troubleshooting
Practice
Break & Prayer
Modalities Review (Flash Animation)
Jeopardy
Workshop Summary

4. 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.

5. 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
CRRT is not a new therapy. The concept of a kinder, gentler way of achieving fluid and metabolic control without compromising patient well being has been studied for years.
Kramer: Using a simple non pumped arteriovenous system that continuously evolve.
The next couple slides briefly present the history of CRRT. In the 1950’s…. Read the slide. In the 1960’s…. Read the slide. However, it wasn’t until 1977 that Dr. Peter Kramer actually described these therapies in the literature. At that time he was experimenting with the new porous membranes. While inserting access catheters, rumor has it that he inadvertently inserted a femoral line into the femoral artery and rather than remove it and replace it with a venous access, he decided to go ahead and use the arterial access without a blood pump to perform the therapy. In this case, the patient’s MAP moves the blood through the extracorporeal circuit. Others followed and refined his technique. In 1980, Paganini…. Read from slide.

6. 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
Kramer: Using a simple non pumped arteriovenous system that continuously evolve.
Undall: Arteriovenous hemofiltration: A new and simple method for treatment of overhydrated patients resistant to diuretics.

7. 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

8. 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
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.
Slower solute & fluid removal - IHD removes fluid & solutes more rapidly than CRRT does.

9. 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

10. 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

11. 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.

12. 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.
A survey in the US shows that approximately 50% are cared jointly by the hemodialysis and ICU nurses. 30% of the institutions the ICU nurse alone performs CRRT
Derek Angus, Rinaldo Bellomo & Robert Star, Selection of patients for acute extracorporeal renal support in general and CRRT in particular Acute Dialysis Quality Initiative Workgroup 2

13. Continuous Renal Replacement Therapy
Transport Mechanisms

14. 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

15. Transport mechanism: DIFFUSION

16. Transport mechanism: ULTRAFILTRATION
Movement of fluid across a pressure gradient.
Positive pressure in
blood compartment
Negative pressure in dialysate compartment
A second important transport mechanism is ultrafiltration. Ultrafiltration is defined as…. Read the slide. The pressure gradient in the extracorporeal circuit is created by positive, negative, or oncotic pressure from non-permeable solutes. For our purposes, ultrafiltration results in removal of fluid (plasma water) from the patient’s blood. The fluid that is removed is sometimes referred to as “UF”.

17. 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
The third transport mechanism used in CRRT is convection. Convection is defined as…. Read the slide. Water is the solvent and the solutes are “dragged” along with the water as it is removed. Convection also drives adsorption of molecules. Adsorption is: 1. Surface adsorption onto the membrane; 2. Bulk adsorption within the membrane when the molecules can permeate it. The adsorption of solutes onto a membrane occurs as a result of the chemical properties of the membrane. These “adsorptive properties” may be influenced by electrical charge or the affinity of the membrane to “soak up” molecules similar to a sponge soaking up water. Surface adsorption allows for molecules too large to pass through the membrane to be deposited on the surface of the membrane. Bulk adsorption describes the adsorption of molecules that are small enough to pass through the membrane but actually are retained in the structure of the membrane.

18. Transport mechanism: CONVECTION

19. 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.

20. Transport mechanism: ADSORPTION
Adsorption: molecular adherence to the surface or interior of the membrane.
As you can see with our cups, a semi permeable membrane separates a concentrated solution from a solution with no solute. In this diagram, very little solute actually passes through the membrane, instead, it adheres to the membrane. Movement of fluid is required for adsorption to occur. Not all membranes possess this adsorptive quality and it is necessary to identify specific properties of the membrane and target molecules in order to predict whether adsorption will play a role in the clearance of a specific substance.
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

21. Continuous Renal Replacement Therapy
Treatment Modalities

22. Modality: SCUF Slow Continuous Ultrafiltration
PRINCIPLE
Ultrafiltration
PROCESS
Usual blood circuit, synthetic membrane and anticoagulation.
Fluid removal occurs due to volume.
APPLICATIONS
Fluid overload, acute and chronic patients.
As this slide shows, the circuit for SCUF is a simple one. Blood enters the extracorporeal circuit through an access line, passes through the hemofilter, and returns to the patient circulation via the return line. As the blood passes through the filter, ultrafiltration takes place and effluent collects in the effluent bag. Effluent is any fluid that exits the hemofilter and is delivered to a waste bag. Pumps control blood flow and fluid removal rates.

23. Modality: CVVH Continuous Veno-Venous Hemofiltration
PRINCIPLE
Hemofiltrattiion Ultrafiltration & Convection.
PROCESS
Blood circuit, filter & anticoagulation.
Fluid removal and replacement solution.
APPLICATIONS
ARF/Critically ill patients.

24. Modality: CVVHD Continuous Veno-Venous Hemodialysis
PRINCIPLE
Diffusion and Ultrafiltration
PROCESS
Blood circuit, filter and anticoagulation. Dialysate pathway provided by pumps using sterile fluid.
APPLICATIONS
Efficient treatment for small molecule clearance (ARF /CRF, critically ill, sepsis.)

25. Modality: CVVHDF Continuous Veno-Venous Hemodiafiltration
Hemodialysis and Hemofiltration
PRINCIPLE
Diffusion, Convection and Ultrafiltration.
Best clearance of small, middle and large molecules.
Pre-dilution can decrease clotting.
Cost increase

26. Summary of Modalities PRINCIPLE SCUF HV & CVVH CVVHD CVVHDF
Ultrafiltration
YES
Convection NO
Diffusion
Dialysate
Replacement Fluid
What is Removed
Fluid
Fluid & some Solutes
Fluid & Solutes

27. } 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
molecular weight,
in Daltons }
“small”
“middle”
“large”
The transport of a molecule through a membrane is governed primarily by its molecular weight.
Generally, the more a molecule weighs, the larger it is in size & the more resistant it is to transport.
Molecular weights are measured in units called daltons.

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

29. Disposables/Machine/Equipments
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

30. CRRT Machines: Current Generation
Dedicated CRRT device
Pump driven volumetric control
Highly automated
Designed for ease of use at bedside
User friendly

31. Supplies CRRT Circuit: Pediatric : Adult
Minimum priming volume with low resistance
Neonatal lines
Pediatric lines
Exchangeable components
Biocompatible membrane
Adult

32. CRRT Competency Management
Organize your CRRT competency assessment
Determine critical competencies to evaluate annually
Tie critical competencies to annual performance reviews
Understand JCIA expectations
Patient Safety Goals
Develop your CRRT competency assessment program
Design a compliant, consistent and effective competency assessment program
Validate CRRT competency
Validate clinical proficiency
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
Keep up with new CRRT competencies
Verify and document new—and existing—competencies, including those for new equipment

33. CRRT Training and Education
Nurses
Critical Care
Nephrology
Physicians:
Ongoing education
Grand Rounds, small groups
BECOME AN ACCEPTED PART OF THE TEAM
Pharmacists
Nutritionists
Ideally, a CRRT training course should be made mandatory for the multi-disciplinary team. (read text)

34. CRRT Education Plan 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.

35. 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

36. 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

37. Acute Initiation Timeline: Example
Defining Roles for the multi-disciplinary team.

38. Communication is Key for a successful CRRT program.

39. Practical information: Techniques and Methods to Perform CRRT

40. Practical information: Techniques and Methods to Perform CRRT

41. 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

42. CRRT Access : What Works?
Pediatrics
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)
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 ml 1.5 ml (Fr 11.5)
19.5 cm ml 1.3 ml (Fr 11.5)
19.5 cm ml 1.1 ml (Fr 10)
Leg position - be creative
Tape on the skin - may need to get creative
Positioning – short lines
Sedation? During initiation ?
Pediatric Perma Cath 28 Cm 0.8 cc 0.85 cc
Strazdins V, etal. RRT for ARF in Children: European Guidelines

43. 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).
During connection of a double lumen catheter to the extracorporeal circuit, care MUST be taken to ensure that the distal lumen is connected with the venous end, and the proximal lumen with the arterial end. Otherwise significant recirculation can take place i.e. blood which is already purifies can be drawn into extracorporeal circuit again, decreasing the effectiveness of treatment.

44. Estimated Total Blood volume in ml/kg
CRRT in Pediatrics
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 ml
Term newborns ml
1-12 months ml
1-3 years ml
4-6 years ml
7-18 years ml
Adults ml
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
Note: From Gunn, V. L. & Nechgyba, C. (2002)
Strazdins V, et al. RRT for ARF in Children: European Guidelines
Artificial Organs, 27(9): Overview of Pediatric RRT in ARF
Baldwin, I. et al, Adequacy Dialysis Quality Initiative, 4th International Consensus Conference

45. 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)

46. Potential Complications of CRRT
Volume related problems
Biochemical and nutritional problems
Hemorrhage
Infections
Thermic loss
Technical problems
Logistical problems
Uf adjusted according to patients clinical state.
Use of Iv pumps/burette and small size syringes in flushing vascular access. Think Small!!
Significant amino acids loss across the hemofilter.
Keep the baby warm to avoid Vasoconstriction . Current generation of crrt machine is equipped with thermic controllers.
Technical – competent bedside nurse to handle and correct alarm conditions . Clotting
Supplies sufficient to run 72 hrs?

47. CRRT Flash Animation (Modes review)
Click Animation

48. Fourth Annual International Conference of Saudi Society of Nephrology
JEOPARDY
CRRT WORKSHOP
Fourth Annual International Conference of Saudi Society of Nephrology
26-29 April 2009
Riyadh, Saudi Arabia

49. 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.