1 Continuous Renal Replacement Therapy (CRRT) Workshop Cyrus Custodio, CNCKing Faisal Specialist Hospital & RCRiyadh, Saudi Arabia
2 Objectives Purpose of CRRT Advantages of CRRT Filter dynamics Transport mechanisms of CRRTModes of therapy & indicationsFlow rate relationshipsPressures & their meaningsBuffer selection
3 Outline for the Workshop IntroductionReview of CRRTPractical Hands On CRRT MachineCRRT InitiationSharing of practical experiences in dealing with the CRRT machine.TroubleshootingPracticeBreak & PrayerModalities Review (Flash Animation)JeopardyWorkshop 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 ARF1977 – Kramer introduces CAVH1980 – Paganini introduces SCUF1984 – Geronemus and Schneider propose CAVHDCRRT 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 therapies1996 – R. Mehta, UCSD, hosts the first international conference on CRRT in San DiegoKramer: 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 overloadSlow, gentle and well tolerated by hypotensive patientsRemove large amounts of fluid and waste products over timeTolerated well by the hemodynamically unstable patientIf 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 creatinineNutritional supportMembrane absorption and removal of humoral mediators of sepsisEffect on mortality ( CRRT vs IHD )Unclear whether either modality is superior in terms of survivalMuch larger prospective controlled studies are requiredConsensus that CRRT can be more safely performed in hemodynamically unstable patients
10 Terminology Hemodialysis transport process by which a solute passively diffuses down itsconcentration gradient from one fluid compartment (either bloodor dialysate) into the otherHemofiltrattiionuse of a hydrostatic pressure gradient to induce the filtration (orconvection) of plasma water across the membrane of the hemofilter.Hemodiafiltrationdialysis + filtration.solute loss primarily occurs by diffusion dialysis but 25 percentor 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 CRRTDerek 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 concentrationIn the case of dialysis, via a semi permeable membraneConcentration gradient necessaryRate of diffusion is dependent on:surface area of filterratio of dialysate flow to blood flowsize of the soluteRemoves small molecules effectively
16 Transport mechanism: ULTRAFILTRATION Movement of fluid across a pressure gradient.Positive pressure inblood compartmentNegative pressure in dialysate compartmentA 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 moleculesThe greater the amount of fluid that moves, the greater the solute lossThe 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.
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- AnaphylatoxinsIt must be noted that movement of fluid is required for adsorption to occur
22 Modality: SCUF Slow Continuous Ultrafiltration PRINCIPLEUltrafiltrationPROCESSUsual blood circuit, synthetic membrane and anticoagulation.Fluid removal occurs due to volume.APPLICATIONSFluid 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.
24 Modality: CVVHD Continuous Veno-Venous Hemodialysis PRINCIPLEDiffusion and UltrafiltrationPROCESSBlood circuit, filter and anticoagulation. Dialysate pathway provided by pumps using sterile fluid.APPLICATIONSEfficient treatment for small molecule clearance (ARF /CRF, critically ill, sepsis.)
25 Modality: CVVHDF Continuous Veno-Venous Hemodiafiltration Hemodialysis and HemofiltrationPRINCIPLEDiffusion, 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 UltrafiltrationYESConvectionNODiffusionDialysateReplacement FluidWhat is RemovedFluidFluid & some SolutesFluid & 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)100,00050,00010,0005,0001,00050010050105molecular 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 CRRTRange of blood flows with a minimum of 20ml/minThermoregulationMaximum safety features
30 CRRT Machines: Current Generation Dedicated CRRT devicePump driven volumetric controlHighly automatedDesigned for ease of use at bedsideUser friendly
32 CRRT Competency Management Organize your CRRT competency assessmentDetermine critical competencies to evaluate annuallyTie critical competencies to annual performance reviewsUnderstand JCIA expectationsPatient Safety GoalsDevelop your CRRT competency assessment programDesign a compliant, consistent and effective competency assessment programValidate CRRT competencyValidate clinical proficiencyMaintain a consistent CRRT validation systemEnsure that clinical proficiency is assessed and validated in a consistent manner with our easy to implement skill sheetsKeep up with new CRRT competenciesVerify and document new—and existing—competencies, including those for new equipment
33 CRRT Training and Education NursesCritical CareNephrologyPhysicians:Ongoing educationGrand Rounds, small groupsBECOME AN ACCEPTED PART OF THE TEAMPharmacistsNutritionistsIdeally, 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 TermsThe Pediatric IdealConcepts related to fluid removalConcepts related to solute removalFormulas related to CRRTComponents of a CRRT SystemCRRT ProceduresProcedures related to initiation of therapyProcedures related to monitoring therapyProcedures related to terminating therapyPotential problems encountered during CRRTIndications for CRRT in the critical care settingCRRT outcomes research12th Annual International Conference on Continuous Renal Replacement Therapy, San Diego, CA, USA.
35 Competencies: Bedside ICU Nurse VerbalizeHow CRRT works (fluid and solute balance, changes in nutrition and medications)Reason for treatmentWhen and how to terminate treatmentHow to troubleshoot alarms (AP, VP, blood leak, error codes, air detector)When and how to recirculate the systemHow to care for catheter and catheter exit siteWhen and how to contact nephrologists or hemodialysis nurseHow to operate extracorporeal circuit warmerDemonstrateHow to calculate fluid balanceHow to assess clotting in the systemHow to adjust AP and VP limits, BFR, UFRHow to verify dialysis and replacement fluid solution and ratesDocument continuing care in nursing notes and CRRT flow chartHighly skilled in troubleshooting alarms
36 Competencies: Nephrology Nurse Knows how CRRT worksReason for treatmentWhen and how to terminate treatmentEquipment operationMost common alarms conditionsWhen and how to reach the nephrology teamFluid balance calculationsAssessment of clottingHow to adjust AP/VP limits, BFR or UFRHow 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 tracingPre/post dilutionSet and check ordersOpaque/non-opaque alarmWhat mode are we in?Transducer maintenanceHelp key, Graphs, scales,Bag/syringe ChangeDialysate/substituate bags preparationChange post-dilution to pre.Alarms settings (automatic)Venous bubble catcher: ↑or ↓ levelArterial chamber: ↑or ↓ levelDe-aerationBlood samplingHand bolus Vs Sub bolusFlushing filtersTemporary DisconnectTerminate treatment with & without blood return
42 CRRT Access : What Works? PediatricsAdultsPatient Size (kg)Vascular Access2.5-106.5 Fr DLC (10cm)10-208Fr DLC (15cm)>2010.8Fr or larger DLC (20cm)PERMAMENT CATHETER36 CM 1.3 cc 1.4 cc40 CM 1.4 cc 1.5 cc45 CM 1.6 cc 1.7 ccTEMPORARY CATHETER24 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 creativeTape on the skin - may need to get creativePositioning – short linesSedation? During initiation ?Pediatric Perma Cath 28 Cm 0.8 cc 0.85 ccStrazdins 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 PediatricsAfter access insertion, staffing in place, CRRT circuit is blood primed for patients < 15kgExtracorporeal circuit volume greater than 10% of patients circulating blood volume.AgeEstimated Total Blood volume in ml/kgPreterm infantsmlTerm newbornsml1-12 monthsml1-3 yearsml4-6 yearsml7-18 yearsmlAdultsmlThe 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 ml100Note: From Gunn, V. L. & Nechgyba, C. (2002)Strazdins V, et al. RRT for ARF in Children: European GuidelinesArtificial Organs, 27(9): Overview of Pediatric RRT in ARFBaldwin, 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/minuteAdvance BFR slowly (15-20 minutes)
46 Potential Complications of CRRT Volume related problemsBiochemical and nutritional problemsHemorrhageInfectionsThermic lossTechnical problemsLogistical problemsUf 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 . ClottingSupplies sufficient to run 72 hrs?
48 Fourth Annual International Conference of Saudi Society of Nephrology JEOPARDYCRRT WORKSHOPFourth Annual International Conference of Saudi Society of Nephrology26-29 April 2009Riyadh, 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.