【持续性肾脏替代治疗crrt英文精品课件】cvvh-continuous veno-venous hemofiltration (65p)

MazenKherallah MD FCCPKingFaisalSpecialistHospital ResearchCenterInternalMedicine InfectiousDiseaseandCriticalCareMedicine CVVHcontinuousveno venoushemofiltration History Kramer1979 Germany InadvertentcannulationofthefemoralarteryledtoaspontaneousexperimentwithC arterio VH patient scardiacfunctionalonecapableofdrivingthesystemlargevolumesofultrafiltratewereproducedthroughthehighlypermeablehemofilter continuousarterio venoushemofiltration systemcouldprovidecompleterenalreplacementtherapyinananuricadult History pediatrics Lieberman1985 USA slowcontinuousultrafiltration SCUF tosuccessfullysupportananuricneonatewithfluidoverloadRonco1986 Italy CAVHinneonatesLeone1986 USA CAVHinolderkids1993 generalacceptanceofpump drivenCVVHaslessproblematicthanCAVH TheIdealModeofRenalReplacementTherapyforCriticallyIllPatients RemoveexcessfluidandtreatfluidoverloadCorrectandcontrolazotemiaCorrectandcontrolelectrolyteimbalancesAssistinmaintainingacid basebalance ThisgoalsmustbeaccomplishedwithoutPrecipitatingadditionalhemodynamicinstability CVVH 1 near completecontroloftherateoffluidremoval i e theultrafiltrationrate 2 precisionandstability3 electrolytesoranyformedelementofthecirculation includingplateletsorredorwhitebloodcells beremovedoraddedindependentlyofchangesinthevolumeoftotalbodywater CRRT Indications SCUFAcutepulmonaryedemaSevereedemainCongestiveheartfailurewithdiuretic unresponsiveoliguriadespiteinotropicsupportHepaticfailureOliguricoranuricpatientswithacuterenalfailureNephroticsyndromeCVVHFDrugintoxicationSepticshockRhabdomyolysisTumor lysissyndromeHyperthermiaSeverelacticacidosis HighVolumeHemofiltrationandTherapeuticPlasmaExchange ThromboticthrombocytopenicpurpuraHUSHyperviscositysyndrome macroglobulinemia cryoglobulinemia andmultiplemyelomaHyperbilirubinemiaFocalglomerulosclerosisRapidprogressiveglomerulonephritisMystheniagravisLambert EatonsyndromeGuillanBarreSyndromeSystemicvasculitis SLE CVVH Advantages PrecisefluidcontrolCanbedoneinpatientswithlowMAPLesshemodynamicinstabilitythanIHDEaseofinitiationLargevolumeofparenteralnutritioncanbeadministeredNoarterialcannulationBettersoluteclearancethanCAVHRequireslesstechnicalsupportandequipmentthanIHF CVVH D ispreferredmodeofCRRT CVVH Disadvantages Anticoagulation bleedingHypotensionHypothermiaHyperglycemiaAirembolismAccesscomplicationRequires1 1nurse patientratioRequiresstrictmonitoringoffluidandelectrolytereplacementtoavoiddeficitsoroverload Hemodialysisallowstheremovalofwaterandsolutesbydiffusionacrossaconcentrationgradient Bloodispumpedalongonesideofasemi permeablemembrane acrystalloidsolutionispumpedintheoppositedirectionontheothersideofthemembrane Solutesofverysmallmolecularweightdiffuseacrossthemembraneinanattempttoequilibratetheirconcentrations UltrafiltrationTheporesinanultrafiltrationmembranearesubstantiallylargerthanthoseinadialysismembrane ultrafiltrationmembranesallowpassageofsolutesupto20 000Daltonsmolecularweight Filtrationacrossthemembraneisconvective similartothatfoundintheglomerulusofthekidney Small e g sodium potassium phosphate bicarbonate andmedium sizedmolecules e g insulin myoglobin certainmedicationsandtoxins crossfreely diffusionandconvectionDuringanyrenalreplacementtherapy therearetwotransportmechanismsthatcanbeinvolvedinthetransferofsolutesacrossasemipermeablemembrane diffusionandconvection Diffusivetransportisdrivenbythesoluteconcentrationgradientsthatexistbetweenbloodanddialysate Solutemoleculesaretransferredacrossthemembraneinthedirectionofthelowersoluteconcentrationatarateinverselyproportionaltomolecularweight Convectivetransportoccurswhenasolutemoleculeissweptthroughthemembranebyamovingstreamofultrafiltrate aprocessthatisalsocalled solventdrag Convectivetransportisindependentofanysoluteconcentrationgradientthatmightbepresentacrossthemembrane Onlythedirectionandforceoftransmembranefluidfluxareimportantdeterminantsofconvectivetransport Duringhemodialysis solutemovementacrossthedialysismembranefrombloodtodialysateisprimarilytheresultofdiffusivetransport Duringhemofiltrationsincenodialysateisused diffusivetransportcannotoccur andsolutetransferisentirelydependentonconvectivetransport Thushemofiltration whichdependsonconvectivetransport isrelativelyinefficientatsoluteremovalfromtheblood Diffusion diffusionsolutemoleculesaretransferredacrossthemembraneinthedirectionofthelowersoluteconcentrationatarateinverselyproportionaltomolecularweight hemodialysisduringhemodialysis solutemovementacrossthedialysismembranefrombloodtodialysateisprimarilytheresultofdiffusivetransport Convection convectionasolutemoleculeissweptthroughamembranebyamovingstreamofultrafiltrate aprocessthatisalsocalled solventdrag hemofiltrationduringhemofiltrationnodialysateisused anddiffusivetransportcannotoccur Solutetransferisentirelydependentonconvectivetransport makinghemofiltrationrelativelyinefficientatsoluteremoval Ultrafiltration Filtrationacrossanultrafiltrationmembraneisconvective similartothatfoundintheglomerulusofthekidney Ultrafiltrationmembranesthatareutilizedinhemofiltersallowthepassageofmoleculeswithamolecularweightoflessthan20 000Daltons Thusionsandsmallchemicalspresentinplasmaarefilteredfreely includingsodium potassium bicarbonate glucoseandammonia Soarelargersolubleendogenoussubstancessuchasmyoglobin insulin andinterleukins andcertainexogenoussubstancescirculatinginplasma includingmedications vancomycin heparin andtoxins endotoxin pesticides Moleculesthatareboundtoplasmaproteinswouldnotbefilteredeffectivelybyanultrafiltrationmembrane FiltrationSpectrum ThehemofiltrationmembraneisacompositestructureconsistingofaninnerthinlayeradjacenttothebloodpathsurroundedbyasupportingsuperstructurethatprovidesmechanicalintegritywithoutrestrictingthepassageofwateroranysolutessmallenoughtopassthroughtheporesoftheinnerlayerHemodialysismembranescontainlong tortuousinter connectingchannelsthatresultinhighresistancetofluidflow Thehemofiltrationmembraneconsistsofrelativelystraightchannelsofever increasingdiameterthatofferlittleresistancetofluidflow TheabilityofasolutetoconvectivelycrossamembraneTheratioofthesoluteconcentrationintheultrafiltratetotheconcentrationintheplasma SC UF Plasma AnSCof1meansthatthesolutefreelycrossesthemembraneandisremovedinthesameconcentrationasintheplasmaAnSCof0meansthatthereisnosoluteremovalduetoeitherlargemolecularsizeortoextensiveproteinbinding SievingCoefficient Severalsyntheticmaterialshavebeendevelopedforuseinhemofiltrationmembranes includingpolysulfone polyacrylonitrile andpolyamide allofwhichareextremelybiocompatible Consequently complementactivationandleukopenia bothofwhicharecommoninhemodialysis occurinfrequentlyduringhemofiltration Thishighdegreeofbiocompatibilityisanessentialfeatureofhemofiltration becausethemembranemayremaininconstantcontactwiththebloodformanydays Biocompatibility Varioussyntheticmaterialsareusedinhemofiltrationmembranes polysulfonepolyacrylonitrilepolyamideallofwhichareextremelybiocompatible Consequently complementactivationandleukopenia bothofwhicharecommoninhemodialysis occurinfrequentlyduringhemofiltration HemofiltrationMembrane Hemodialysismembranescontainlong tortuousinter connectingchannelsthatresultinhighresistancetofluidflow Thehemofiltrationmembraneconsistsofrelativelystraightchannelsofever increasingdiameterthatofferlittleresistancetofluidflow phosphatebicarbonateinterleukin 1interleukin 6endotoxinvancomycinheparinpesticidesammonia HemofiltrationMembrane Hemofiltersalloweasytransferofsolutesoflessthan100daltons e g urea creatinine uricacid sodium potassium ionizedcalciumandalmostalldrugsnotboundtoplasmaproteins AllCVVHhemofiltersareimpermeabletoalbuminandothersolutesofgreaterthan50 000daltons phosphatebicarbonateionizedCa interleukin 6endotoxinvancomycinheparinpesticidesammonia albumin protein boundmedications platelets VascularaccessThemostimportantcircuitcomponentisthevascularaccesscatheter Achievingadequatecentralvenousaccessininfantsandyoungchildrencanbedifficult TheuseofdoublelumenhemodialysiscathetershassimplifiedCVVHvascularaccessinourcenter Doublelumencathetersaredesignedtowithdrawbloodfromalargeveinthroughholesinthesideofthecatheterthatentertheoutsidelumen thearteriallumen Bloodisreturneddownthecentral venous lumenanddeliveredthroughasingleholeinthetipofthecatheterthatextendsashortdistancefurtherintothevesselbeyondthe arterial holesonthesideofthecatheter Thisdesignisintendedtoreducerecirculationofhemofilteredbloodasmuchaspossiblebywithdrawingfromasitethatismoredistal totheheart andreturningtoamoreproximallocationwithinthesamelargevein Whenthecatheter soveralldiameteristoolargeandcloselyresemblestheinternaldiameterofthevessel poorarterialflowmayresultfromcollapseoftheveinagainstthesideholesofthecatheter Thisproblemmayberesolvedbyreversingflow withdrawingfromthevenousandreturningthroughthearteriallumen Althoughsomerecirculationisthenunavoidable theuseoflargefilterswithhighclearancerateseasilyovercomesthisproblem BloodFlowRate Intheory pumpspeedshouldbesufficienttoprovideafilterbloodflowrate Qb thatyieldsanadequateultrafiltrationrate UFR withoutseverelydehydratingtheblood Qbisdeterminedbypumpspeed vascularaccesscatheterlength lumendiametersandpatency bloodviscosity andpatencyofthehemofilter sbloodpathway i e howmanyofthehemofilter shollowfibershaveclottedorareobstructedbyentrapmentofair Itshouldberememberedthatasbloodflowsdowneachofthetinyhollowfibersinthehemofilter fluidisremoved sothatbythe venous endofthehemofilter eachhollowfibercontainsbloodthatismoreconcentrated Hematocritrisesandthenumberofactivatedplateletsincreases alongwiththeconcentrationsofotherclottingfactors Whenthebloodistoodehydrated theriskofclottingincreases BloodFlowRate FiltrationFraction Thedegreeofblooddehydrationcanbeestimatedbydeterminingthefiltrationfraction FF whichisthefractionofplasmawaterremovedbyultrafiltration FF UFRx100 QPwhereQPisthefilterplasmaflowrateinml min QP BFR x 1 Hct BFR bloodflowrate UltrafiltrateRate FF UFRx100 QPQP BFR x 1 Hct Forexample whenBFR 100ml minandHct 0 30 i e 30 QP 70ml min Afiltrationfraction 30 promotesfilterclotting Intheexampleabove whenthemaximumallowableFFissetat30 aBFRof100ml minyieldsaUFR 21ml min QP thefilterplasmaflowrateinml min SoluteClearance SCXUFR RateofSoluteClearance UreaClearance InCVVH ultrafiltrateureaconcentrationandBUNarethesame cancelingoutoftheequation whichbecomes Curea UFRCurea ml min 1 73m2BSA ureaclearance Curea UFRx1 73pt sBSAThus inachildwithbodysurfacearea 1 0m2 aCureaofabout15ml min 1 73m2isobtainedwhenUFR 8 7ml minor520ml hr Thissameclearancecanbeachievedinthe1 73m2adolescentwithaUFR 900ml hr Curea ml min 1 73m2BSA ureaclearance Whentargetureaclearance Curea issetat15ml min 1 73m2 theequationcanbesolvedforUFR 15 UFRx1 73 pt sBSAUFR 15 1 73 8 7ml minCurea ml min 1 73m2BSA Sluggishness Afiltrationrateofmorethan25 30 greatlyincreasesbloodviscositywithinthecircuit riskingclotandmalfunction OncoticpressureincreasesasProtein freeplasmaisfiltered atonepointtheoncoticpressurewillequalizethehydrostaticpressureandfiltrationwillcease Replacement Ultrafiltrateisconcurrentlyreplacedwithacombinationof customphysiologicsolutionsringer slactatetotalparenteralnutritionsolutionsInpatientswithfluidoverload aportionoftheultrafiltratevolumeissimplynotreplaced resultinginpredictableandcontrollablenegativefluidbalance Pre dilution Sludgingproblemsarereduced buttheefficiencyofultrafiltrationiscompromised astheultrafiltratenowcontainsaportionofthereplacementfluid Pre dilutionwillreduceclearanceofsolutes Replacementfluid potassium PotassiumisusuallyexcludedfromtheinitialFRFformulainpatientswithrenalfailure Eventually mostpatientsneedsomepotassium andphosphate supplementation aphysiologicconcentrationofpotassiummustbeaddedtoeachofthefourFRFbagsifinstead16mEqofKClwereaddedtoasinglebag serioushyperkalemiacoulddevelopquickly ReplacementFluid Ringer s ManyadultsaresuccessfullytreatedwithCVVHusingLactatedRinger ssolutionastheFRF Ringer sis convenientcheapereliminatesriskofpharmacyerrorinformulationoftheMichiganbagsMichiganFRFmaybepreferableincriticallyillchildren especiallyinfants butwehavenotcomparedthetwosolutionssystematically ReplacementFluid Commercial FluidBalance PrecisefluidbalanceisoneofthemostusefulfeaturesofCVVH Eachhour thevolumeoffiltrationreplacementfluid FRF isadjustedtoyieldthedesiredfluidbalance physiologicreplacementfluid universityofmichiganformula ReplacementFluid finalconc universityofmichiganformula DrugClearance Dosing Drugtherapyshouldbeadjustedusingfrequentbloodleveldeterminations orbyusingtablesthatprovidedosageadjustmentsinpatientswithreducedrenalfunction Bennett stablesrequireanapproximationofpatient sGFRtheCVVH GFR isapproximatedbytheultrafiltraterate UFR plusanyresidualrenalclearanceusingBennett stables inmostCVVHpatients drugdosingcanbeadjustedfora GFR intherangeof10to50ml min Anti coagulation TopreventclottingwithinandshutdownoftheCVVHcircuit activeanti coagulationisoftenneeded heparin citrate local vs systemic Anti coagulation Patientswithcoagulopathiesmaynotneedanyheparin ifpatient sACTis 200secondsbeforetreatment wedonotuseheparincoagulopathiesspontaneouslyimprove oftensignaledbyfilterclotting Anti coagulation heparin Patientswithcoagulopathiesmaynotneedanyheparin whentheACTis 200seconds aloadingdoseofheparin 5 20units kgisgivenheparinasacontinuousinfusion initialrate5units kg hr into prefilter limbofcircuitadjustheparinratetokeepACTfromthevenouslimb postfilter 160to200seconds Anti coagulation citrate CitrateregionalanticoagulationoftheCVVHcircuitmaybeemployedwhensystemic i e patient anticoagulationiscontraindicatedforanyreason usually whenaseverecoagulopathypre exists CVVH DmodehascountercurrentdialysisacrossthefiltercartridgeCVVH Dhelpspreventinducinghypernatremiawiththetrisodiumcitratesolution Anti coagulation citrate CitrateregionalanticoagulationoftheCVVHcircuit 4 trisodiumcitrate prefilter citrateinfusionrate filtrationrate ml min x60min x0 03replacementfluid normalsalinecalciuminfusion 8 CaClinNSthroughadistalsitedialysate Na117 glucose100 200 K4 HCO322 Cl100 Mg1 5Ionizedcalciuminthecircuitwilldropto 0 3 whilethesystemiccalciumconcentrationismaintainedbytheinfusion Srameketal IntensiveCareMed 1998 24 3 262 264 PRISMA FlowRates BloodFlow 10 180ml minReplacementsolutionflow 0 4500ml hrwithCVVH0 2000ml hrwithothermodesDialysateflow 50 2500ml hrFluidremovalflow 10 2000ml hrwithSCUF0 1000ml hrothermodesEffluentflow dialysateplusultrafiltrate max5500ml h PRISMA PressureMonitoringranges Accesslinepressure 50to 250Returnlinepressure 50to 350Prefilterpressure 50to 500Effluentline 350to 50 experimental highflow High volumeCVVHmightimprovehemodynamics increaseorganbloodflow anddecreasedbloodlactateandnitrite nitrateconcentrations experimental septicshock Zerobalanceveno venoushemofiltrationwasperformedwithremovalof3Lultrafiltrate hfor150min Thereaftertheultrafiltrationrateincreasedto6L hforanadditional150min Rogiersetal EffectsofCVVHonregionalbloodflowandnitricoxideproductionincanineendotoxicshock experimental septicshock Rogiersetal EffectsofCVVHonregionalbloodflowandnitricoxideproductionincanineendotoxicshock scenarioI Septicshock day 3ofhospitalization Ultrafiltrateproductionistightlycontrolledbyaflowregulatorontheoutflowportofthefilter dryweight 20kgtoday sweight 24kgbloodflowthroughfilter 75cc minultrafiltrateproduction 0 5cc min scenarioI Withthislowlevelofultrafiltrateproduction fluidsIN OUTarestillnotbalanced thechild sintakeis100cc hrIV andoutputis 30ccUF 10ccurine 40cc hour scenarioII Septicshock day 4ofhospitalization Ultrafiltrateproductionisincreasedto90cc hour tightlycontrolledbyaflowregulatorontheoutflowportofthefilter dryweight 20kgtoday sweight 24kgbloodflowthroughfilter 75cc minultrafiltrateproduction 1 5cc min scenarioII FluidsIN OUTarebalanced thechild sintakeis100cc hrIV andoutputis 90UF 10ccurine 100cc hour question howmuchfluidvolumecanbededicatedtonutrition eitherparenteralorenteral scenarioIII Septicshock day 2ofhospitalization CVVHisinitiated andultrafiltrateisproducedatarateof1440cc hour tightlycontrolledbyaflowregulatorontheoutflowportofthefilter dryweight 20kgtoday sweight 23 6kgbloodflowthroughfilter 75cc minultrafiltrateproduction 25cc min scenarioIII Anetdeficitof100cc hrisdesired Abodyweightlossoftwokilogramsormoreisexpectedoverthenext24hours scenarioIII questions 1 ultrafiltrationproduction