Principles of dialysis The dialysis process TheconceptoIdialysis,thatispartition(separation)oIsubstancebetweentwosolutionsbyuseoI semipermeable membrane, is quite simple. Extracorporeal dialysis employs the artiIicial kidney (dialyzer) as semipermeable membrane, while Intracorporeal dialysis employs the peritoneal membrane. Physical principles of dialysis DiIIusion,UltraIiltrationandOsmosisarethebasicphysicalprinciplesoIdialysis. Diffusion isthenet directional movement oI molecules occurring Irom a solution oI higher concentration to a solution oI low concentration. Ultrafiltration isthemovementoIsolventacrossasemipermeablemembraneinresponse toapressurediIIerenceappliedacrossthemembrane.IIthesolutesdissolvedinthesolventissmall enoughtopermeatethemembrane,theyaredraggedalongwiththesolventandcrossovertotheother side,andthiscalled Convection. Osmosis themovementoIthesolvent(e.g.water)IromthesideoIlow concentration to the side oI higher concentration. Diffusion IItwosolutionoIdiIIerentcompositionareplacedondiIIerentsideoIasemipermeablemembrane, soluteswillmoveIromthesolutionwiththehighestconcentrationtothesolutionwiththelowest concentration. The rate oI movement will depend on: 1.The concentration gradient Ior the solute between the two solutions2.Permeability oI the membrane to the solute 3.SurIace area oI the membrane. 4.ThesizeoIthesoluteishighlycorrelatedwithitsmolecularweight.Theheavier,largersolute moves more slowly along the concentration gradient than smaller lighter solutes. Thus, dialysis is most eIIective in removing small solutes and less eIIective in removing larger solutes, particularly those over 1000 Dalton. Molecular weight in Dalton oI some nonionic substances SubstanceMolecular weight in Dalton BUN Urea Creatinine Ethanol Methanol Glucose Vit B12 Albumin 28 60 113 46 33 180 1355 68000 5.BloodproteinaIIectsthediIIusivetransportoIsoluteacrossthemembranebytwodiIIerent mechanisms: A.thebindingoIthesolutetoprotein:DiIIusiblesubstancemaybindtoproteinsIorming dialysismembraneimpermeablecomplex.SuchsolutesarenolongeravailableIor diIIusion(40-50oImeasuredcalciuminpatientbloodisavailableIordiIIusion).The percentageoIthetotalconcentrationoIadiIIusiblesolute(actuallyIreetodiIIuse)is described as 'solute activity. B.the Gibbs-Donnan eIIect: Blood proteins are dialysis membrane impermeable, negatively chargedandtendtoaccumulateatthemembranesurIaceduringdialysis.Coresponding numbers oI membrane permeable cations such as sodium, calcium, magnesium must then retaininthebloodtopreserveelecroneutrality.Thisresultsinimbalanceinthe concentrationoIionsacrossthedialysismembrane.Theprotein-inducediontransport asymmetry is called the 'Gibbs-Donnan eIIect. It indirectly aIIects the magnitude oI the concentration gradients required to drive diIIusion across dialysis membrane. AssolutemovementcontinuesoveraperoidoItime,theconcentration falls inthesolutionoIhigher concentration, rises inthesolutionwiththelowerconcentration,andthetwosolutionsapproacheach otherincompositioni.e Equilibrium.AsaresultoIthisdissipationoItheconcentrationgradient,the transIeroIsoluteslowswiththetime.ThemaximumrateoIsolutetransIeroccursinitiallywhenthe concentration gradient is greatest. Schematic diagram oI diIIusion No hydrostatic pressure is applied |Van Stone et al 1994, Physiology oI peritoneal dialysis in handbook oI dialysis 2nd edition| ThedissipationoItheconcentrationgradientcanbeminimizedandthetransIeroIsoluteoptimizedby increasing the volume oI the Iluids. a)Inastaticsystem(comparabletoperitonealdialysis)thisisaccomplishedbyreplacingthe recipient Iluid with Iresh solution at periodic intervals. b)In a Ilowing system (comparable to hemodialysis) this accomplished by increasing the Ilow rate oI parent Iluid (blood) or recipient Iluid (dialysate). BothartiIicialandnaturalmembranesaremorepermeabletosmallsolutesthanlargesolutes.Thus, dialysisismosteIIectiveinremovingsmallsolutesandlesseIIectiveinremovinglargersolutes, particularly thoseover 1000 daltons.The surIace area oI themembrane available Ior diIIusion aIIects the amount oI solute transIerred.

Mechnisms oI solute removal in intermittent hemodialysis and continuous renal replacement therapy IHDCRRT Small solutes (lees than 300 D)DiIIusionConvection (CVVH) DiIIusion (CVVHD) Middle molecules (500-5000)DiIIusion Convection Convection DiIIusion LMW protein (5000-50 000)Convection DiIIusion Adsorption Convection Adsorption Large molecules (m0re than 50 000ConvectionConvection Ultrafiltration TheprocessoIwaterremovalIromthebloodstreamiscalled ultrafiltration; theIluidremovedis the ultrafitrate.TheUFduringdialysisis perIormed Ior the purpose oI removingwater accumulated by ingestion oI Iluid or by metabolism oI Iood during the interdialytic period. It is essential to prescribe and controltheIluidremovalratesothattotalIluidremovedduringdialysiswillbeequaltothetotalIluid gained since the previous dialysis or Irom the dry weight.

Schematic diagram oI osmotic ultraIiltration Nohydrostaticpressureisapplied.Trianglesrepresentosmoticagentintroducedtorightcompartment. This causes an early water shiIt to the right (ultraIitration), but this is later reversed iI the osmotic agent is also small enough to diIIuse along the concentration gradient Irom right to leIt. Thus only solutes oI such sizethattheydonoteasilypermeatethesemipermeablemembranearecapableoIexertingasustained osmoticIorce.|SorkinMIetal1994,PhysiologyoIperitonealdialysisinhandbookoIdialysis 2nd edition| Schematic diagram oI hydrostaticultraIiltration The applicationoIexternal pressure IorcesmovementoIwater IromleIt to right.Lowmolecular weight constituentswillbesweptthroughthemembranewiththiswater(solventdrag.).Indialysissettingthe pressuregradientisgeneratedbymanipulationiIdialysisIluidparameterssuchaspressurevolumeor Ilow. |Von Stone MI et al 1994, Physiology oI peritoneal dialysis in handbook oI dialysis 2nd edition|

Mechanism oI UltraIiltration In Hemodialvsis: 1. Hydrostatic pressure TheprimarydrivingIorceIorultraIiltrationisthehydrostaticpressurediIIerenceacross the membrane, which is the %ransmembrane Pressure (%P, expressed in millimeters mercury (mmHg).TheTMPisdeterminedbytheaverageormeanpressureintheblood compartment minus themeandialysatecompartmentpressure.TherelationshipoIultraIiltrateto TMPisentirelydependentonthemembrane(Dialyzer)properties.ThepermeabilityoIdialyzer membranes to water is high, varies consonsiderably, and is a Iunction oI membrane thickness and poresize.ThetotalcapacityoIthedialyzerIorultraIiltrationisgivenbythe Ultrafiltration Coefficient (KUF).%e KUF is defined as te number of milliliters of fluid per our tat will be transferred across temembranepermmHgpressuregradientacrosstemembrane .TheKUFoImostdialyzer ranges Irom 2 to 6ml/hour. The relationship betweenultraIiltration, KUF and TMP is expressed as: How do you calculate UF rate Irom KUF? II one needs to remove 2 kg during a period oI 4 hours 1.Add the volume oI saline that will be given at the end oI dialysis (usually 300 ml) and the amount oI ingested Iluid during dialysis (e.g., 100ml). 2.This means that 2.4 L will have to be removed during 4 hours dialysis i.e.2.4 X 1000 /4 600 ml/hour. 3.WhenusingadialyzerwithKUFvalueoI4.0ml/hour,theTMPwillneedtobesetat 600/4 150 mm Hg. N.B. (II the dialyzer KUF is 6 the TMP should be 100 mm Hg). Ultrafiltration rate (ml/hr KUF X TMP

. Osmotic Ultrafiltration Osmotic ultraIiltrationdoes play anindirect rolein total ultraIiltration;water shiIts Irom intracellular to the extracellular compartment which occur during hemodialysis (so-called plasma reIilling) can be optimized by introduction oI an eIIective concentration oI an osmotic agent into theextracellularspace.Sodiumisemployedinsomedialysispracticeespeciallyduringsodium proIiling B In peritoneal dialvsis: 1. Osmotic Ultrafiltration The primarydrivingIorce Ior ultraIiltraionin peritoneal dialysis is the Osmoticgradient (OsmoticUltrafiltration). Osmosis is themovementoIthesolvent(egwater)IromthesideoIlow concentrationtothesideoIhigherconcentrationthroughasemipermeablemembrane.TheresultoI thismovementoIwaterwillbeequalizationoItotalsoluteconcentrationonbothsidesoIthe membrane. OsmoticultraIiltraionduringperitonealdialysisisachievedbyaddinglargeamountoIglucoseto dialysissolution.Peritonealdialysissolutionordinarilycontain1.36(1.5),2.27(2.5),3.86 (4.25). The osmotic pressure generated by glucose will draw water Irom the blood and tissues into the dialysate. . Hydrostatic pressure The hydrostatic ultraIiltraion eIIect is oI minor importance ndications and contraindications of dialysis

ndications for Dialysis -n Chronic Renal Failure InpatientswithchronicrenalIailureIactorstobeconsideredbeIoreinitiatingdialysisshould includecomorbidconditionsandpatientpreIerence.TimingoItherapyisdictatedbyserumchemistries and symptoms. bsolute indications Uremic Pericarditis Uremic Encephalopathy or Neuropathy Pulmonary edema (unresponsive to diuretics) Severe Hypertension Severe hyperkalemia Intractable acidosis Severe Bleeding diathesis Persistent gastrointestinal symptoms S.Creatinine more than 12 mg/dl, BUN more than 100 mg/dl B Relative indications Mild encephalopathy or neuropathy Severe edema (unresponsive to diuretics) Progressive gastrointestinal symptoms Recurrent GI 'itis: stomatitis, gastritis, dudenitis, pancreatitis Ascitis without hepatic disease Anemia reIractor to Erythropoietin Mild Bleeding diathesis Pruritus InIectious complications Depression C Earlv indications Decrease ideal body weight Decrease in muscle mass (decrease s creatinine or its clearance) Decrease in s.albumin to less than 4 g/l GFR less than 15 ml/min (by I iothalamate) S. Creatinine ~10 mg/dl and bun ~100 mg /dl Decrease in s.transIerrin Low total cholesterol Growth retardation in children D Specific indications for peritoneal dialvsis Patients with cardiovascular or hemodynamic instability Hemodialysis patients with vascular access Iailure or can not be created (e.g. diabetic patients) High risk oI anti coagulation Patients in the older age group (over 65) and small children Severe hemodialysis-related symptoms or disequilibrium Social reason ndications for Dialysis other than chronic renal failure 1.Acute renal Iailure 2.Poisons and Drug intoxication 3.Hypercalcaemia 4.Hyperuricemia 5.Hypothermia 6.Metabolic alkalosis (special dialysis solution required)

Dialvzable drugs and Poisons (partial list a)Barbiturates: Phenobarbital -Pentobarbital -Amobarbital b) lcohols : Methanol -Ethanol -Ethylene glycol -Isopropanol c)nalgesics : Acetylsalicylic acid -Methylsalicylate d)Metals : Calcium -Potassium -Sodium -Lithium e)Endogenous toxins: Uric acid -Uremic toxins -Hyperosmolar state I)Halides : Bromide g)Miscellaneous: Theophylline -Mannitol -Radiocontrast -Thiocynate - Boric acid -Aniline NB: 1.Dialysis Ior poisoning should be considered only when supportive measures areineIIective or there is impending irreversible organ toxicity. 2.HemoperIusion is required in some cases

Factors to be considered in determine drug`s dialyzability: 1. Dialysis related Iactors: Dialyzer membrane characteristics SurIace area Blood Ilow rate Dialysate Ilow rate Degree oI ultraIitration Duration oI dialysis

2. Drug related Iactors . Availability oI the drug in the plasma Drug pharmacokinetic characteristics Drug molecular weight (500 cross the membrane more readily) Drug solubility (water soluble are dialyzable than lipid soluble)

Factors Determinants for Dialysis Factors determining the mode oI chronic dialysis should include medical and non medical Iactors which have an impact on the treatment modality. Physicians have the responsibility to discuss the therapeutic options and oIIer their advice and recommendations about the choices. In general renal transplantation should be recommended as the preIerred mode oI renal replacement therapy in whom surgery and immunosupression is saIe and Ieasible. Medical Factors Age Comorbid medical illnesses Patient survival Patient rehabilitation Quality oI liIe B Non Medical Factors Government-imposed Economic limitations Physicianand Patient bias Resource availability Social ,Religious ,Cultural mores Availability oI transplantation Family support Cost , race , sex , reimbursement Contraindications of Dialysis therapy Principally there is no absolute contraindication to dialysis therapy. Advanced age in and oI itselI is not a contraindication to dialysis therapy. Many elderly are physiologically equivalent to young patients. Relative contraindications to dialvsis therapv Advanced malignancy (except multiple myeloma) Alzheimer`s disease Multi-inIarct dementia Hepatorenal syndrome Advanced liver cirrhosis with encephalopathy Hypotension unresponsive to pressors Terminal illness Organic brain syndrome B Contraindication for Peritoneal dialvsis Absolute Peritoneal IibrosisPleuroperitoneal leakRelative Minor Chronic Ostomies Severe hypercatabolic state Fresh aortic prosthesis Recent Abdominal surgery Recent Thoracic surgery Extensive Abdominal adhesions Quadriplegia Blindness Physical handicaps Mental Retardation Relative Minor Polycystic Kidney disease Diverticulosis Obesity Peripheral vascular disease Hyperlipidemia Social .

Hemodialysis Definitions Vascular access Membranes used for hemodialysis Dialysate Hemodialysis machine Hemodialysis procedure Anticoagulation in hemodialysis Patients' monitoring during dialysis Complications during hemodialysis Chronic complications of hemodialysis DEFTO$ Hemodialvsis (HD) The blood passesthroughanextracorporealcirculationwhereitisseparatedIromdialysisIluid byartiIicialsemi-permeablemembrane.SolutesmoveacrossthemembraneonlybydiIIusion.The dialysissolution compriseswaterandelectrolytes.Thedialysis membrane isusuallymadeIrom cuprophane,acellulosederivative.NewersyntheticmembranesoIpolymericstructurearemore permeable to water and solutes and more biocompatible with the blood than cuprophane membranes. Hemofiltration (HF) HemoIiltrationisaIormoIdialysisinwhich a negativepressure iscreatedonthesideoIa highly permeable dialyzer (HemoIilter) opposite to the blood comartment.This sucks the plasma Iluid and thesolutedissolvedinitacrossthemembrane.ThisprocessisknownasConvection`.HighvolumeoI plasmaisultraIiltratedsimultaneouslyreplacedbypyrogenIreehemoIiltrationIluidintavenously.The basicdiIIerencebetweenhemodialysisandhemoIiltrationisintheprincipleoIsolutetransport.During hemodialysisthesoluteisremovedbydiIIusionandtheIluidbyultraIiltration.Bycontrast,during hemoIiltration, the solute removal is accomplished by convection, that is solvent drag. ontinuous Arterivenous Hemofiltration (AJH) CAVH isanextracorporealtreatmentinwhichIluid,andelectrolyte,andlowmolecularweight solute are removed Irom the body by convective transport. The technique utilizes the patient arterial pressure to move the blood in the circuit and an ultraIiltrate with thesamecharacteristicsoIplasmaisgenerated.ThesubstitutionoItheamountoIIluidlostby ultraIiltration with sterile replacement solution permit: (1)To correct electrolyte and acid base imbalance. (2)Lower the patient`s BUN concentration Hemodiafiltration (HDF) AcombinedhemodialysisandhemoIiltrationprocedure.Dialysis solutionandhighlypermeable membraneareusedtoobtaindiIIusionandultraIiltration.TheIluidbalanceismaintainedbyinIusinga hemIitration Iluid. solated Ultrafiltration (UF) IsolatedUltaIiltrationisamethodwherebyIluid,electrolytesandsubstancewithlowmolecular weightareremovedIromtheplasmawaterbymeansoIconvection.HalItooneandahalIliterscanbe removed per hour using conventionalhemodialyser. No diIIusion occurs during this procedure.When UF precedes or Iollows hemodialysis; the combined process is called Sequential UF, or Sequential dialysis. Hemoperfusion (HP) HPisaprocesswherebybloodispassedthroughacartridgepackedwithactivatedcharcoalor carbon,(i.e.thecartridgepacedinsteadoIdialyserinthebloodcircuit).ItismoreeIIectivethan hemodialysis in clearing the blood oI many protein-bound drugs, because the charcoal will compete with the plasma protein in Ior the drug, adsorb the drug, and thereby remove it Irom the circulation. Similarly, hemoperIusionwillremovemanylipidsolubledrugsIromthebloodmuchmoreeIIicientlythan hemodialysis.HemoperIusionispreIerredthanHemodialysis inGlutethimide,Methaqualone, Theophylline and Phenobarbital drug poisoning. '$CULR CCE$$ Acute Hemodialvsis Jascular Access-Aoncuffed ateters (Guide 2 DOQI) A.HemodialysisaccessoIlessthan3weeks`durationshouldbeobtainedusinganoncuIIed,ora cuIIed, double-lumen percutaneously inserted catheter. B.These catheters are suitable Ior immediate use and should not be inserted beIore needed. C.NoncuIIed catheters can be inserted at the bedside in the Iemoral, internal iugular, or subclavian position. D.The subclavianinsertion site shouldnot be used in a patientwhomayneed permanentvascular access.) E.Chestx-rayismandatoryaItersubclavianandinternaliugularinsertionpriortocatheteruseto conIirm catheter tip position at the caval atrial iunction or the superior vena cava and to exclude complications prior to starting hemodialysis. F.Where available, ultrasound should be used to direct insertion oI these catheters into the internal iugular position to minimize insertion-related complications. G.Femoralcathetersshouldbeatleast19-cmlongtominimizerecirculation.NoncuIIedIemoral catheters shouldnot be leItin placelonger than 5days and should beleIt in placeonlyin bed-bound patients. H.NonIunctional noncuIIed catheters can be exchanged over a guidewire or treated with Urokinase as long as the exit site and tunnel are not inIected. I.Exit site, tunnel tract, or systemic inIections should prompt the removal oI noncuIIed catheters Temporary vascular access: Catheters B"uinton-Scribner external arteriovenous shunt Catheters 1. Single lumen, 1961 2. Double lumen, 1980s These catheters made oI TeIlon, Silastic, or Polyurethane Veins used: Femoral vein Subclavian vein Internal iugular vein Indication: 1.Acute renal Iailure 2.ESRF patients whose permanent access is immature 3.Patients on peritoneal dialysis requiring temporary hemodialysis4.Patient Ior plasmapheresis 5.Patients Ior venovenous or arteriovenous continuous renal replacement therapy. Contraindication oI Subclavian and Internal iugular vein catheterization 1.Patients with acute respiratory distress (cannot be supine or in Trendelenberg position.2.Patients with subclavian vein stenosis 3.Abnormal coagulation parameters Nursing management (Guide) AlloIthesecathetersarepronetoinIectionthereIoreaseptictechniquewheninitiatingand terminating dialysis is oI outmost importance. ThecapsandportsshouldbewrappedinadressingsoakedinBetadineIor5minutesbeIore initiating and ending dialysis. Theexit site should becleanedwith Peroxide andBetadine aIterevery treatment, and a sterile dressing should be applied. The appearance oI the exit site especially redness or drainage must be documented CareIulheparinizationisnecessaryandshouldbeguidedbymanuIacturer'sinstructionand accordingtothesize(ordeadspace)oIeachcatheter.Indwellingheparinshouldbeaspirated beIoredialysistoavoidexcessiveheparinization.ApreIerablemethodoImaintainingcatheter patencyistheinstillationoI1000-5000UoIheparinintothecatheterimmediatelyaIter dialysis.Thevolumenecessarytodeliverheparindependsonthesize(deadspace)oIthe catheter. Clamp the catheter Iirmly andonce to avoidblood suctioninto the tipoI the catheter by dropper action Donot attempt toinstill salineinto a clotted catheter. Thiswill Iorce the clotinto thevascular system. Minimal handling oI the catheter is strongly advocated, and then only experienced personnel. II thecatheterisneededIorparentralnutritionorbloodtransIusionaLeuer-lokconnections should be used to prevent air embolus or blood loss. Bases Ior cannula selection 1.Subclavian and internal iugular vein catheter can be liIt in place Ior several weeks while Iemoral catheter almost always removed within 3 days. 2.Once subclavian and internal iugular vein catheters patient can be dialyzed as an outpatient while patient with Iemoral catheter must be hospitalized. 3.Femoral catheter is easily insertable while subclavian and internal iugular vein catheters insertion requires a skilled operator. 4.Complication Irom Iemoral catheterization usually minor and never liIe threatening in contrary to subclavian and internal iugular vein catheters insertion. 5.New Iemoral catheter insertion Ior each dialysis is the best approach in bacteraemic patients

Complications

FemoralSubclavianJugular Early

Pain at insertion site Bleeding Puncture oI the Iemoral artery, Intestinal perIoration

Pain at insertion site Bleeding Puncture oI subclavian artery pneumothorax Hemothorax Brachial plexus iniury Puncture oI superior vena cava Mediastinal haemorrge Peric.temponade Arrhythmias Pain at insertion site Bleeding Puncture oI carotid artery Pneumothorax Hemothorax Arrthmias

Late

Groin hematoma Retroperitoneal hematoma InIection Catheter clotting InIection Catheter clotting Subclavian vein thrombosis or stricture InIectionCatheter clotting Thrombosis and stricture are quite low incidence

Management of technical problems 1.Poor blood flow Lowering patient's head iI using subclavian or Jugular vein Turning patient's head to opposite side iI using subclavian or Jugular V Apply external pressure to the exit site Rotate the catheter shaIt 180 degrees Reverse the lines (last resort) Replace the catheter iI the catheter has been in place Ior less than week. 2. Clotting Proper heparinization postdialysis ClampthecatheterIirmlyandoncetoavoidbloodsuctionintothetip oI the catheter by dropper action Finrinolytic agents such as urokinase or streptokinase Replace the catheter iI the catheter has been in place Ior less than week. 3 KinkingOReplace the catheter iI the catheter has been in place Ior less than week. %unneled uffed ateter Placement: %vpe and Location: (DOQI) A.Tunneled cuIIed venous catheters are the method oI choice Ior temporary access oI longer than 3 weeks`duration.(TheyalsoareacceptableIoraccessoIshorterduration.)Inaddition,some patientswhohaveexhaustedallotheraccessoptionsrequirepermanentaccessviatunneled cuIIedcatheters.ForpatientswhohaveaprimaryAVIistulamaturing,butneedimmediate hemodialysis, tunneled cuIIed catheters are the accessoI choice. Catheters capableoI rapid Ilow rates are preIerred. (Evidence/Opinion) B.ThepreIerredinsertionsiteIortunneledcuIIedvenousdialysiscathetersistherightinternal iugularvein.Otheroptionsinclude:therightexternaliugularvein,theleItinternalandexternal iugularveins,subclavianveins,Iemoralveins,ortranslumbaraccesstotheinIeriorvenacava. Subclavianaccessshouldbeusedonlywheniugularoptionsarenotavailable.TunneledcuIIed catheters should not be placed on the same side as a maturing AV access, iI possible. (Evidence) C.Fluoroscopy is mandatory Ior insertion oI all cuIIed dialysis catheters. The catheter tip should be adiustedtotheleveloIthe cavalatrialiunction orintothe rightatrium toensureoptimalblood Ilow. (Atrial positioning is only recommended Ior catheters composed oI soIt compliant material, such as silicone.) (Opinion) D.Real-time ultrasound-guidedinsertion is recommended to reduce insertion-related complications. (Evidence/Opinion) E.ThereiscurrentlynoprovenadvantageoIonecuIIedcatheterdesignoveranother.Catheters capableoIarapidbloodIlowratearepreIerred.Catheterchoiceshouldbebasedonlocal experience, goals Ior use, and cost. (Evidence/Opinion)

Permanent 'ascular ccess For Hemodialysis Patient Evaluation Prior to ccess Placement

ConsiderationRelevance Patient HistorvHistory oI previous central venous catheterPreviousplacementoIacentralvenouscatheterisassociatedwithcentral venous stenosis. Dominant armTo minimize negative impact on quality oI liIe, use oI the nondominant arm is preIerred. History oI pacemaker useThere is a correlation between pacemaker use and central venous stenosis. History oI severe congestive heart IailureAccesses may alter hemodynamics and cardiac output. History oI arterial or venous peripheral catheterPreviousplacementoIanarterialorvenousperipheralcathetermayhave damaged target vasculature. History oI diabetes mellitusDiabetesmellitusisassociatedwithdamagetovasculaturenecessaryIor internal accesses. HistoryoIanticoagulanttherapyoranycoagulation disorder AbnormalcoagulationmaycauseclottingorproblemswithhemostasisoI accesses. PresenceoIcomorbidconditions,suchasmalignancy orcoronaryarterydisease,thatlimitpatient`sliIe expectancy Morbidity associated with placement and maintenance oI certain accesses may not iustiIy their use in some patients. History oI vascular accessPreviouslyIailedvascularaccesseswilllimitavailablesitesIoraccesses;the causeoIapreviousIailuremayinIluenceplannedaccessiIthecauseisstill present. History oI heart valve disease or prosthesisRate oI inIection associated with speciIic access types should be considered. History oI previous arm, neck, or chest surgery/traumaVasculardamageassociatedwithprevioussurgeryortraumamaylimitviable access sites. Anticipated renal transplant Irom living donorTemporary access may be suIIicient. Phvsical Examination

Physical Examination oI Arterial SystemCharacter oI peripheral pulses, supplemented by hand-held Doppler evaluation when indicated AnadequatearterialsystemisneededIoraccess;thequalityoIthearterial system will inIluence the choice oI access site. Results oI Allen testAbnormal arterial Ilow pattern to the hand may contraindicate the creation oI a radial-cephalic Iistula. Bilateral upper extremity blood pressuresPressures determine suitability oI arterial access in upper extremities. Physical Examination oI Venous SystemEvaluation Ior edema .EdemaindicatesvenousoutIlowproblemsthatmaylimituseIulnessoIthe associated potential access site or extremity Ior access placement Assessment oI arm size comparabilityDiIIerentialarmsizemayindicateinadequateveinsorvenousobstruction which should inIluence choice oI access site. Examination Ior collateral veinsCollateral veins are indicative oI venous obstruction. Tourniquet venous palpation with vein mappingPalpation and mapping allow selection oI ideal veins Ior access. ExaminationIorevidenceoIpreviouscentralor peripheral venous catheterization UseoIcentralvenouscathetersisassociatedwithcentralvenousstenosis; previousplacementoIvenouscathetersmayhavedamagedtarget vasculature necessary Ior access. ExaminationIorevidenceoIarm,chest,orneck surgery/trauma Vascular damage associatedwith previous surgeryor trauma maylimit access sites. Cardiovascular EvaluationExamination Ior evidence oI heart IailureAccesses may alter cardiac output.

OArteriographyisuseIultoavoidextremityischemiainpatientswithdiminishedpulsesinwhom access in the extremity is still desired. However, the Work Group concluded that arteriography is only rarely required. OVenipucture in the non-dominant Iorearm should be minimized in patients with chronic renal Iailure OPermanentV.Accessshouldbecreatedwhencreatininclearancedropsto~15ml/minuteor3-6 months prior to initiation oI hemodialysis. OTheriskoIsubclavianveinstenosisinpatientwhohavehadprevioussubclaviancatheterishigh thereIore angiographic assessment is recommended prior to access placement. %vpes of permanent J. Access rteriovenous Fistula B.rteriovenous Graft . rteriovenous Fistula (1966) Description. The arteriovenous Iistula consistsoI surgical anastomosis oI an adioining artery andvein. Thediversion oI the arterial blood causes the used veins to become enlarged and prominent and stronger because oI the greater Ilow oI the arterialized blood through them.

Selection oI Permanent Vascular Access and Order oI PreIerence Ior Placement oI AV Fistulae (Guide 3 DOQI) 1. TheorderoIpreIerenceIorplacementoIAVIistulaeinpatientswithkidneyIailurewhowill become hemodialysis dependent is: a.A wrist (radial-cephalic) primary AV Iistula (Evidence) b.An elbow (brachial-cephalic) primary AV Iistula (Evidence/Opinion) 2. II it is not possible to establish either oI these types oI Iistula, access may be established using: a.An arteriovenous graIt oI synthetic material (eg, PTFE) (Evidence) or b.A transposed brachial basilic vein Iistula (Evidence) 3. CuIIed tunneled central venous catheters should be discouraged as permanent vascular access.

Tvpes and blood vessels used. Radiocephalic Fistula : Anastomosis oI Radial artery and Cephalic vein Brachiocphalic Fistula: Anastomosis oI Brachial artery and Cephalic vein BrachioBasailic Fistula : Anastomosis oI Brachial artery and Basilic vein Ulner artery is inIrequently used nastomosis. End oI the vein to side oI the artery End oI the vein to end oI the artery Side oI the vein to side oI the artery Surgical Technique. The details of the surgical technique are bevond the scope of the Tips Postoperative Care. 1.Elevate the arm to minimize edema. 2.Avoid tight dressings 3.Check the Iistula daily Ior, thrill, hematoma, and evidence oI ischemia 4.AIter 4-5 days some exercises could be started a.A tourniquet may be placed around the upper arm to cause distention oI the veins, leave it Ior about 30 minutes and may be repeated several time each day. b.Hand exercise, such as squeezing rupper ball, while the tourniquet is in place. c.Warm compresses to speed the venous distention. 5.Arteriovenous Iistula could be used aIter 2 months.

. rteriovenous Graft (1974 / 1977) Description. Abiologic,semibiologicorprostheticgraItimplantedsubcutaneouslyandattachedtoan artery and vein. It is used in patients who do not have adequate vessels to create an arteriovenous Iistula. It can be used aIter 2-3 weeks.

Type and Location oI Dialysis AV GraIt Placement IIaprimaryAVIistulacannotbeestablished,asyntheticAVgraItisthenextpreIerredtypeoI vascularaccessGraItsmaybeplacedinstraight,looped,orcurvedconIigurations.Designsthatprovide themostsurIaceareaIorcannulationarepreIerred.LocationoIgraItplacementisdeterminedbyeach patient's unique anatomical restrictions, the surgeons's skill, and the anticipated duration oI dialysis) 1.Subcutaneous autogenous vein grafts. A segmentoI patient'sownveinis attached to an artery a vein and used Ior dialysis aIter becomes prominent and healing. 2.Bovine grafts. Carotid artery Irom cattle is used aIter special processing. 3.Svntheticgrafts:Manysyntheticmaterialsareavailable|Macron,PolytetIluoroethylene(PTFE)| insertedsurgicallyandrequire2weekstomature. PolytetraIluoroethylene(PTFE)tubesare preIerred over other synthetic materials. 4.PTFEgraftwithtranscutaneousdeviceforneedlefreeaccess.Thesystemisaccessedthrough selI-sealing device with locking ring. A special set attaches to the blood tubing. Surgical Technique. The details of the surgical technique are bevond the scope of the Tips Postoperative care. As in Arteriovenous Iistula

ccess Maturation A.AprimaryAVIistulaismatureandsuitableIorusewhenthevein`sdiameterissuIIicienttoallow successIul cannulation, but not sooner than 1 month (and preIerably 3 to 4 months aIter construction.) B.The Iollowing procedures may enhance maturation oI AV Iistulae: 1.Fistulahand-armexercise(eg,squeezingarubberballwithorwithoutalightlyapplied tourniquet) will increase blood Ilow and speed maturation oI a new native AV Iistula. (Opinion) 2.SelectiveobliterationoImaiorvenoussidebrancheswillspeedthematurationoIaslowly maturing AV Iistula. (Opinion) 3.When a new native AV Iistula is inIiltrated (ie, presence oI hematoma with associated induration and edema), it should be rested until swelling is resolved C.PTFE dialysis AV graIts should not routinely be used until 14 days aIter placement. Cannulation oI a newPTFEdialysisAVgraItshouldnotroutinelybeattempted,even14daysorlongeraIter placement, until swelling has gone down enough to allow palpation oI the course oI the graIt. Ideally, 3 to 6 weeks should be allowed prior to cannulation oI a new graIt. D.Patientswithswellingthatdoesnotrespondtoarmelevationorthatpersistsbeyond2weeksaIter dialysisAVaccessplacementshouldreceiveavenogramorothernoncontraststudytoevaluate central veins. E.CuIIedandnoncuIIedhemodialysiscathetersaresuitableIorimmediateuseanddonotrequire maturation time. (Evidence)

Using Permanent Jascular Access PoorvascularaccessisalimitingIactortopatientsurvivalonhemodilysis.ThereIoregreatcare must be taken to maintain adequate vascular access. Kind of the needleSixteen,IiIteenandIourteengougeneedlesareusedIorhemodialysis.Smallerdiameter(highergouge) needles seriously limit the blood Ilow rate. HigherIlowratemaybepossiblebyusingbiggerdiameterneedle,butatconsiderableincreasein negative pressure which increased the possibility oI sucking air into the system or damaging the intima oI vessels. Resistance to the Ilow occurs in long needles, therefore the shortest practical needle is desirable The selection oI the needle depends on: 1.mount of subcutaneous tissue to be penetrated 2.Size of the vein (access 3.ngulation of the vein Placing The Needle in the Access: 1.Aseptic technique is essential. 2.Local anesthesia may be used in some patient. 3.Localize the Iistula orgraIt; depth , angulations , maximum thrill , and site of insertion , hence the angle oI needle insertion is decided (~ 45 degree). 4.Insert the inlet (Arterial) needle proximal to the Iistula or close to arterial anastomosis oI the graIt bv 3 cm at least, to avoid intimal damage and the subsequent thrombosis. 5.The return (venous)needle should inserted pointing toward theheart approximately 5cm proximal tothearterialneedle.Thisoppositedirectionmeanttoavoidrecirculation.Sucheventmaybe undetected , the patient gets poor dialysis.

Remarks : A.Blackbloodsyndrome :Whenrecirculationisquiteseveretheblood becomesveryacidic(pH 7 ) the RBCs cannot carry oxygen and the blood appears very B.II venous needle cannotbeinserted ,oItenveincanbeIoundinanotherlimborsingleneedle technique to be used. C.Inserttheneedlesatleast2cmormoreIromtheprevioussiteseachtimetoensurecomplete healing oI the vein. D.Initiate heparenization aIter insertion oI both needle,.( to avoid hematoma ). Removing the needle Itisimportanttomaintainadequatepressureeitherbyhandortightpressuredressing overthe puncture site Ior 15-20 minutes aIter needles is removed. Care required between dialvsis 1.Good hygienic condition is important. Instruct the patient to wash Iistula arm with water and soap predialysis. 2.Advise the patient to remove the dressingIew hours aIter dialysis . 3.Advise the patient to avoid trauma to the access or to sleep on the same arm. 4.Educate the patient to: a)Feel the bruit over the Iistula (Touch) b)Observe Ior signs oI inIection; redness, pain, swelling, exudates (Look). What to say to the patient to protect his access? OMake sure your nurse or technician checks your access beIore each treatment. OKeep your access clean at all times.OUse your access site only Ior dialysis.OBe careIul not to bump or cut your access. ODon't let anyone put a blood pressure cuII on your access arm. ODon't wear iewelry or tight clothes over your access site. ODon't sleep with your access arm under your head or body. ODon't liIt heavy obiects or put pressure on your access arm. OCheck the pulse in your access every day.

Membranes used for hemodialysis Tvpes of semipermeablemembranesused for hemodialvsis.

1. Organic Cellulose (C6H10O5) membranes and its derivatives : CelluloseisthemostcommontypeoIdialyzermembrane.Itis obtainedIromtreatedwood productsandcottonwithheatandchemicalsandIormedintosheetsorextrudedthroughdiesashollow Iibers;e.g.regeneratedcellulose,cuprammoniumcellulose(cuprophan),cuprammoniumrayon, saponiIied cellulose ester. Cellulose acetate and triacetate are other widely used cellulose substances. Nature. The membrane is visualized as a thin sheet with tiny pores. These pores are small enough to hold backbloodcellsandplasmaproteins,yetlargeenoughtopermitwatermoleculesandmanysolutesto passthrough.Selectivepermeabilityisimprovedbymakingthemembranethinner,increasingthe numbers oI channels between Iibers , or increasing the diameter oI passages. PositiveandNegativefeatures. HollowIibershaveminimalcomplianceandpermitpreciseTMP calculation.Theyareinexpensive.Cellulosemembraneshoweverhavemoreincompatibilityproblems than do synthetic membranes specially cuprophan.

2.Synthetic membranes: Synthetic membranes include Polyacrylonitrile (AN ,PAN) PolysulIone Polycarbonte polymide Polymethylmethacrylate (PMMA) Ethylene-vinyl alcohol copolymer Nature. Theyareathin,smoothluminalsurIace,supportedbyasponge-likewallstructure.Allhave ultraIiltration coeIIicients oI 20 to 70 ml/hr/mmHg or more. Positivefeatures. Middlemoleculeclearanceisgreaterthancellulosemembranes. B.Microglobulinis removed by adsorption to the membrane 100 mg /treatment. They have better biocompatibility with blood than cellulose membrane. Negative features. Very expensive. Automated ultrIiltration control is required because oI very high water permeability SigniIicant protein loss by adsorption. BackIiltration Irom the dialysate and risk oI bacterial or endotoxin contamination, due to high hydraulic permeability embrane biocompatibilitv: MaterialusedinmanuIactureoIdialysismembraneisassociatedwithsomedegreeoIblood-material interaction. Complement activation thatoccursduringdialysiswith cellulosemembraneisinstigated by: 1)FreehydroxylradicalsonthemembranesurIace.2)AcellulosematerialcalledLimulus-Amebocyte-Lysate-Reactive-Material(LALRM).ThisactivationleadstoreleaseoIhistamine,thromboxane, interleukin 1, and tumor necrosis Iactor as well as direct action on blood cells. The clinical maniIestation varies Irom minimal symptoms to severe anaphylactic reaction. (See membrane reactions) Dialyzers A. %vpes of Dialvzers (ArtiIicial kidneys) DialyzersconsistsoIaseriesoIparallelIlowpathsdesignedtoprovidealargesurIacecontact areabetweenbloodanddialysate.Thedialyzingmembranehasporesvaryingbetween11-30um.The membranesareprotected bydialyzershellwith4ports,2Iorbloodand2Iordialysate Dialyzersare broadly classiIied as: 1 Coil dialvzer2 Parallel Plate dialvzer3 Hollow Fiber dialvzer Coil dialvzer .( are of historic interest OBasicallyconsistsoIaIlattenedcellulosetubing wrappedasacoilandthroughwhichpatient`s bloodIlowduringdialysis.ThebloodchannelswaslongtoobtaintheneededsurIacearea,and resistance was high. UF was unpredictable and blood leak were Irequent. Parallel Plate dialvzer OStructure:SheetsoImembranesareplacedbetweensupportingplatesTheplateshaveridgesand grooves to support the membrane and allow Ilow oI dialysate along it. Resistance to blood Ilow is low.The surIace area vary Irom 0.25 to 1.5 msq. OAdvantages: Bloodvolumeisabout50-100mlat100mmHgincreaseswithhighTMP(bulging sheets) Heparin requirement usually low, minimal clotting in the blood compartment. UlttrIiltration is reasonably predictable and controllable. ODisadvantages: Formation oI local thrombi around inlet and outlet ports and corners due to uneven blood Ilowattheseparts.ThesemayleadtobacterialgrowthandendotoxinIormation, thereIore plates are not oIten reused. HollowFiber dialvzer OStructure: It consists oI numerous hollow Iibers (capillaries) through which the patient`s blood Ilow. The hollow Iibers are tiny its diameter ~150-250 um. The wall thickness as little as 7 um. The number oI Iibers may be 20,000 or more ,depending upon length ,kind oI membrane , and surIace area oI the dialyzer. Hollow Iiber is the most commonly used dialyzers OAdvantages: It contained low blood volume in relation to surIace area 60-90 ml (low priming volume). Resistance to blood Ilow is low. UltraIiltration can be precisely controlled, They are well adapted to reuse. ODisadvantages: Deaeration oI the Iiber predialysis is necessary to prevent air lock oI the Iibers. UnevenblooddistributionattheinIlowheaderspaceleadstorelativestagnation centrally,withreducedperIusionandclottingoIsomecenterIiberswiththesubsequent high residual blood volume and aggravation oI anemia. More heparin is required Ior most oI the patients. Adverse patient reaction due to residual toxic products oI sterilizing agent. . Dialvzer specifications DataaboutthedialyzerincludestheIollowing inIormationwhichguidesthedialysispersonnelto select proper dialyzer Ior each patient : 1.Type oI the dialyzer :(see the previous tip) 2.Material oI the membrane :(see the previous tip) 3.UltraIiltration CoeIIicient ,(KUF). (see the previous tip Ior UltraIitration) The KUF isdeIined as the number oImilliliters oI Iluid per hour that will be transIerred acrossthemembranepermmHgpressuregradientacrossthemembraneTheKUFoImost dialyzer ranges Irom 2 to 6 ml/hour. II KUF is low (or high) the permeability to water is low (or high).InvivoKUFisoItenlowerby5-30thaninvitrovalueTherelationshipbetween ultraIiltration, KUF and TMP is expressed as: Ultrafiltration rate (ml/hr KUF X TMP 4.Clearance.Usually reported at blood Ilow rates oI 200,300,and 400 ml/minute a Urea .A higheIIiciencydialyzerwith thin,large surIace area,wide pores, good design willremoveahigherpercentageoIwasteproducts.TheeIIiciencyoIadialyzerin removingureacanbedescribedbyaconstantreIerredtoas Masstransferurea coefficient-Ko .This constantinIluencetherelationbetweenthebloodIlowratetothe clearance. clearance .Dialyzers oI low eIIiciency have in vitro KoA value oI less than 300 ; used Ior acute dialysisand smallpatient. Dialyzers oI moderate eIIiciency have in vitro KoAvalueoI300-600;highereIIiciencydialyzershaveKoAmorethan600-700.Once KoAoIthedialyzerisknownanomogramcanbeusedtopredictthebloodwaterurea clearance(Kw)atgivenblood(Qb)anddialysate(Qd)Ilowrate.TheinvitroKoAis usuallyoverestimated,thereIore invivovalueshouldbeestimatedIromanother nomogram. b Creatinine.JitB12. Thedialyzercreatinineclearanceis~80oIureaclearance. VitaminB12dialyzerclearancerangeis30-60ml/minute.ItisusedasindicationIor clearance oI higher molecular weight. Molecular weight of some nonionic substances in mol wt. BUN 28Urea 60Creatinine 113 Albumin 68000 Glucose 180 Vit B12 1355Ethanol 46 Methanol 33 5.SurIace area oI the dialyzer: NormallylargesurIaceareaoIthedialyzehavehighureaclearance.Howeverdialyzer design and the thinness oI themembrane are quit important. Large surIace area is an undesirable Ieature when an unsubstituted cellulose membrane is used. It increases the degree oI complement activation. 6. Theprimingvolume:ItisrelatedtothemembranesurIacearea;usually60-90mlinhollow Iibers. II this added to the priming volume oI the blood lines(100-150 ml), the total extracorporeal circuit will be 160-270 ml 7.Mode oI dialyzer Sterilization Exposure oI the dialyzer to Ethylene Oxide gas Gamma irradiation - becoming popular Steam autoclaving - becoming popular Dialysate ThetermdialysatereIerstotheIluidandsolutethathavecrossedamembranei.e.eIIluent dialysisIluid.However,incurrentrenaliargonalldialysisIluid,Ireshorusediscalleddialysate. Dialysate is sometimes called 'bath". The composition oI dialysate is nearly correspondto that oI plasma water. Composition and function of dialysate Composition oI dialysate: There are Iive compounds 1.Sodium chloride 2.Sodium acetate or Sodium bicarbonate 3.Calcium chloride 4.Potassium chloride 5.Magnesium chloride. Glucose may be included in some Iormulas. The use oI bicarbonate in concentrate causes calcium and magnesium precipitate because oI high pH. Function of Dialysate: 1.It carries away the waste materials and Iluid removed Irom the blood by dialysis. 2.It prevents removal oI essential electrolytes. 3.It avert excess water removal during dialysis. Types of dialysate:Two types oI dialysis solutions are discussed in the Iollowing 2 tips 1.Acetate Dialysate 2.Bicarbonate Dialysate cetate Dialvsate Acetate is physiologically compatible with blood and metabolized to bicarbonate in the liver. It is mixedwithwaterinproportioningsystem,usually1partconcentrateand34partsoIwater,toIormthe dialysate. A typical compositionoI acetate containingdialysate (aIter mixing) contains, Sodium 135-145 mEq/L, potassium 0-4 mEq/L, Calcium2.5-3.5 ,Magnesium 0.5-1 mEq/L, Acetate 35-38 mEq/L, Chloride 100-119 mEq/L, Dextrose 11 mEq/L ,PCo20.5 mmHg. Advantages: 1.Stable during storage 2.Not prone to bacterial contamination 3.A wide variety oI Iormulations are available4.The delivery system is simple and less costly Disadvantages: 1.Serum bicarbonate may decrease early during dialysis. 2.Acetateaccumulationcontributetocardiovascularinstabilitywithvasodilatationand hypotension, nausea , vomiting, and post dialysis Iatigue. 3.Acetate dialysate is not suited Ior high eIIiciency or high Ilux dialysis. Serum bicarbonate isdepletedandacetatelevelmayexceedtherateatwhichthelivercanmetabolizeit. ThereIore cardiovascular instability may be severe and disequilibrium may occur. Bicarbonate Dialvsate CalciumandmagnesiumwillnotremaininsolutionwithbicarbonatebecauseoIlowhydrogen ioncontent(highpH).Tosolvethisproblem,twoseparateconcentrateareused.Theproportioning (delivery) system mix and monitor three liquids instead oI two. 1.The ' concentrate2.The 'B concentrate OR powder3.Purified water OThe'A -indicatingacidiIied-concentratecontainssodium,calcium,magnesiumand potassium,chloride.TomaintainlowpHenoughtokeepthecalciumandmagnesiumin solution when mixed into dialysatea small amount oI acetic acid is included. OThe'B -indicatingbicarbonate-concentratecontainsthesodiumbicarbonate.Sodium chloride may be included in some preparation to raise the total conductivity. ODrv concentrates.ManuIacturers utilizes a delivery system that accepts a closed container oI dry (powder) bicarbonate onto a special holder. Warm water passesthrough the column producing a saturated solutionoI bicarbonate that is proportionedwithwater thenwith the A concentrate by conductivity controlled Ieed back system (e.g. Bicart.). The advantageoI thistechniqueavoidtheproblemsoIbacterialgrowthinbicarbonateconcentrateand reduces the cost oI storage.

Chemicals in bicarbonate concentrates in mEq/L(aIter mixing)

TheproportioningsystemmixthetwocomponentssimultaneouslywithpuriIiedwatertoIorm the product oI dialysis solution, iust beIore it goes to dialyzer. During mixing carbon dioxide will begeneratedasaresultacidandbicarbonatereaction.ThecarbondioxidegeneratedwillIorm ComponentNaKCaMgClHco3CH3COO Concentrate A8123.50.787.2-4 Concentrate B59---2039- Total14023.50.7107.2394 carbonic acid , which lower the pH oI the Iinal bicarbonate containing solution to ~ 7-7.4 . In this pH calcium and magnesium remain in solution.

Negative Ieatures oI bicarbonate dialysate 1.Liquid'Bisnotstable.Somestabilizerordrysodiumbicarbonatemaybemixed.Themixing process requires care to avoid much loss oI Co2 ; it must be used within 24 hours. 2.Bicarbonate concentrate isvery susceptible to bacterial contamination which should be avoided . II the container has beenopened Iormore than 72 hours it should not be used. All containers Ior mixing, holding, or dispensing B concentrate must be scrupulously sanitized at regular intervals. 3.Many Iormulation oI 'A concentrate are available thereIore care must be exercised to ensure that the concentrates selected are correct Ior the delivery system being used. Hemdialysis Machine

Hemodialysis machine consists oI.1.Blood pump 2.Dialvsate deliverv svstem 3.Safetv monitors 4.Options 5.Svstem disinfection:

LOOD PUP Function : It circulate the blood through the dialyzer back to the patient. Kinds: Presently peristaltic roller pumps which works by progressive compressing special segments oI the blood tubing are used. Pumpocclusion: Occlusionmeansthattheroller compressthe tubingsegmentsagainstthesemicircular housingsuIIicientlytoclosethelumencompletelyatthatpoint.ConsistentpumpIlowratesrequire precise occlusion. Overocclusion may crack the tubing and rupture oI the pumping segment. II occlusion isincomplete,therewillbebackIlowoIthebloodwitheachstroke,inaccurateIlowrateandredcell damageTheIlowrateIoradultis~4timespatientbodyweightml/minute,upto600ml/minuteinhigh eIIiciency and high-Ilux dialysis.

DALYSA% DLJ#Y SYS% : Function OAppropriate blending oI concentrate and water Ior preparation oI Iinal dialysate. OTo monitor dialysate Ior temperature, composition, and blood leak OTo control dialysate pressure or ultraIiltration rate. OTo regulate the dialysate Ilow rate through the dialyzer. ODeareation oI water OProvide protective mechanisms to isolate the blood circuit and the patient Irom unsaIe dialysis. OSystem Ior disinIection and cleaning Types OSingle batch svstemOContinuous proportioning svstem O Sorbent regenerative svstem . $ingle batch system (is of istoric interest) . Continuous proportioning system (early1960s) Central.AllthedialysissolutionusedIordialysisisproducedbymixingtheconcentratewithpuriIied water and pumped to each machine Odvantage . Cost eIIective ODisadvantage .Not permitting dialysate composition modiIication Individual : Each dialysis machine proportions its own concentrate with the puriIied water. Odvantage1.PermittingdialysatecompositionmodiIicationbyselectingdiIIerentconcentrateoraltering the mixing ratio. 2.There is signiIicant saving in time. 3.Less bacteriologic and chemical contamination. 4. Reduced the risk oI human error. ODisadvantages1.Complex sophisticated system 2.Costly3.Troubleshouting may be diIIicult and needs a Iactory-trained service technician. Methods of mixing in proportioning svstem1.Matched pumps2.Matched metering valves 3.Matched hydraulic-accumulation cylinders 4.Electronic Ieedback circuit. Details of mixing are bevond the scope the Tips C.$orbent regenerative systemIor renewing dialysate. At present it is rarely used.

Heating OThe physiological range oI dialysate temperature is 36-42 c OTemperature below 36 patients will complain oI cold and uncomIortable. OTemperatureabove42proteindenaturecanoccurandabove45redbloodcellswillhemolyze.cardiorespiratoryarrestanddeath(Iromhyperkalaemiaandhypoxemia)asaconsequenceoI overheated may occur. Deaeration or Degassing Water contains considerable amount oI dissolved air and microbubbles. Once negative pressure is applied and water is warmed the air comes out oI the solution as expanding microbubbles.Bubbles causes. 1.ArtiIacts on conductivity, temperature sensors and Ilow meters 2.When bubbles cross themembraneinto the bloodIoamingoccur andincreases potentialIor clot Iormation, hemolysis and occlusion oI the Iibers. 3.It decreases the surIace area oI the dialyzer 4.ItblockthedialysateIlowchannelssubsequentlydialysatepressuredropsandthedialysate surIace area incompletely utilized Ior solute transport Deareationdevicesuseswarmersalongwithnegativepressure (-600mmHg)tobringthedissolvedair out oI the solution.An air trap or coalescing Iilter then capture the air and vents them out. Dialysate pressures ThedialysatedeliverysystemmustbecapableoIgenerating positiveandnegativedialysatepressures (~ - 400 to 200). OIndialysismachineswithout an ultraIiltration controller thedialysate pump islocated at theline leading Irom the dialyzer to the drain. This allows the machine to create a negative pressure in the dialysate compartmentoI thedialyzer. Thenegative pressure is generated by partial occlusion oI dialysatehoseproximaltothedialyzer.ToincreasetherateoIultraIiltration,negativedialysate pressures(suctionpressures)areoItenrequired.TransmembranouspressureisaresultantoIthe blood compartment and dialysate compartment pressures. OHighpositivepressureisrequiredinsituationinwhichultrIiltrationcoeIIicientortheblood compartmentpressurearehightolimitstherateoIobligatoryultraIiltration.Higherpositive pressure(350)maybenecessarywithhigh-IluxmembranesHowever,backIiltrationoccurs whendialysatepressureisgreaterthanthatoIbloodcompartment,e.g.atthebloodoutlet. Transport oI endotoxin Iragments into the blood in such membranes. Dialysate Flow The standard dialysate Ilow rate is 500 ml/minute.When high-eIIiciency and high-Iluxdialyzer are used highdialysateIlowratebetween700and1000isrequiredalongwithhighbloodIlowrate.HighIlow rates are neededIor: 1.Optimum use oI dialyzer surIace area Ior solute transport.2.WithhighdialysateIlowrateapositivedialysatepressureisgeneratedwhichlimitstherateoI obligatory ultraIiltration.

SAF%Y OA%O#S: . Monitors for blood circuit 1. rterial pressure monitorLocations.Proximal to the blood pump Function. 1.Itreadsthearterialpressureatthesegmentbetweenthepatient'sneedlesiteand proximaltothebloodpumpwhichrepresentthenegativepressurecreatedbytheroller pump.2.ItidentiIieshowmuchsuctionisbeingplacedonthearterialwallandguardagainst excessive suctionon thevascular access, eg if suddenlv the arterial pressure increases from 100 to 200 mmHg this could indicate clotted or dislodged needle. low patient BP or kink in the arterial line.3.Resistance within the needle (Iunction oI the gauge and needle length). 4.ItprovideanindexoIvascularaccessbloodsupplyrelativetotheIlowdemandbythe blood pump.5.AguidetoappropriatenceoIneedleplacementorkinkorobstructionintheblood segment between the patient and the monitor. Mechanism. Thepressureis monitoredbymechanicalorelectronicmanometers(pressure transducers) . Electronic transducer is more sensitive and have rapid response . 'enous pressure monitorLocation. Just distal to the dialyzer, usually attached to the top oI the venous air trap. Function.1.ItreadsthevenouspressureatthesegmentbetweenthepointaIterthedialyzerand beIore the blood reenters the patient's body.2.It represent the resistanceoI the blood returning to the patientvia thevenousneedle eg if suddenlv the venous pressure increases from 50 to 150 mmHg this could indicate kink inthevenousline.clottedairtraporthevenous needlemavbeclottedormaligned Suddendroppingvenouspressureoccurswhenthevenousneedleispulledout.wet transducer or clotted arterial chamber3. It may indicate venous stenosis proximal to the needle site. Mechanism.As in arterial pressure monitor. . 'enous air trap and air detector Location. 1. Just distal to venous pressure monitor. 2. OIten second air trap on the arterial line is also used. Function. Topreventairentryintothepatientortothedialyzer.Itisusedalsotomeasurethe pressure in that segment oI blood circuit. Mechanism. Whenairbubblesenteredthebloodcircuitasensorreactedthroughultrasonic transducerorlightbeambystoppingthebloodpump,clampingthevenousline,andactivating audiovisual alarms.

. Monitors for dialysis solution circuit 1. Conductivity Location . BeIore dialysate reaches the dialyzer FunctionTo guard against excessive diluted or concentrated dialysis solution. Mechanism . When conductivity meter (conductivity probe) detects high or low conductivitythe machineautomaticallysoundsanalarmandputsthedialysateintobypassmodesothat no dialysate Ilow to the dialyzer. ExposureoI the blood tohyperosmolar dialysate can lead tohypenatraemia andother electrolyte disturbances.ExposureoIthebloodtohypoosmolardialysatecanresultsin hyponatraemiaand rapid hemolysis.

. Temperature Location.BeIore the dialyzer Function.To avoid high temperature Mechanism. Throughatemperaturesensor,hightemperatureactivateanaudiovisualalarm simultaneously with bypass mechanism. . ypassvalve or mechanism II the conductivityor Temperature Iound to beout oIlimits a bypass valve is activated todivert dialysate around the dialyzer directly to the drain. 4. lood leak detector Location . In the eIIluent dialysate line Function. Itguardsagainstundetectedbloodlossduringdialysis.Themaximumlimitto hemoglobin present in dialysate is 70 mg/L (corresponding to blood loss oI ~0.4 ml/minute ) aIter which the blood pump is stopped. Mechanism. A beam oIlightisdirected through a column oIdialysateonto a photoelectriccell.A change in translucence and light scatter in dialysate reduces the light received by the photocell, stopping blood pump and activating audiovisual alarms. 5. Dialysate pressure or transmembranous monitor Function. TomonitortheultraIiltrationwithanupperlimitsavoidsexcessivelevel(theusual preset range 0 to -500 mmHg). Excessive TMP may lead to rupture oI the dialyzer and secondary deareation (cause air accumulation). Mechanism. The monitor may have automatic or manually set limits, so that extrusion outside the limits trigger an audiovisual alarm. OP%OAS A HODALYSS AHA: 1.Heparin pump 2.Bicarbonate 3.Variable sodium 4.Controlled UltraIiltration5.Programable ultraIiltration 6.Dialysate urea sensor |on-line Kt/V monitor|7.Single blood pathway. SYS% DSAF%OA: AlldialysisunitsmusthavewrittenpoliciesthedealwiththedialysisIluidpathwayanddialysis machine. DisinIection procedure should be done on regular base according to manuIacturer's instructions. Target. To control bacterialcontamination. HIV, HCV and HBVviruses areknown to be inactivated by common household bleach. Methods 1.Heat disinIection requires temperature greater than 85-90 C 2.Chemicals disinIection such as Iormaldehyde ,sodium hydrochloride and acetic acid Machine surIaces, patient's chairs, surrounding Iurniture, equipment should be routinely wiped with 10 bleach solution Iollowing every patient dialysis. Blood spills should be cleaned immediately.Leak prooI bags should be used to transport linen soiled with blood or body Iluid ALA# DU#AC HODALYSS- P#OL SOLJAC CUD LASj hen an alarm is activated during dialvsis do the following. 1.IdentiIy which alarm has been activated.2.IdentiIy the cause. 3.correct the cause 4.Resume dialysis iI saIe to do so ProblemManagement 1.Power

OTurn the system oII and on; iI still no power, check the power cord; make sure power is available OCheck the Iuse . rterial and venous Pressure

OCheck to see that blood pump is running and connected properly OCheck to see iI blood Ilow rate has changed ODetermine iI patient has coughed or moved OCheck to seeiI the monitor line is leaking OCheck the blood line Ior kinks or leaks OEnsure the monitoring lines are connected toproper drip chambers

.1 High venous pressure

OManipulate the needle and or the line. II the access is small, a tourniquet must be used, being certain thebloodpumpisoII..RecantationwithnewneedleiIneeded,theoriginaloneshouldbeleItin place until the end oI dialysis. to avoid undue bleeding as the patient is heparinized OAdiustthebloodIlowrate,Properheparnization,Treataccessproblem,andProperneedleand needling OExtreme care must be exercised when dialyzing a patient with high venous pressure O-This increases the baseline TMP and obligatoryultraIiltration will occur O-Single-needle device is occasionally impossible to use, because with highvenous pressure ,venous return will be impaired and blood recirculation will be high

. ncreasein negative pressure: (Excessive inflow suction) Management oI increased negative pressure: OManipulation oI the arterial needle is similar to that oI venous needle. In most cases the needle may have to be replaced with the same precaution as with venous needle OTreat the cause.OProper needlingOAsses the access .ir detector alarm

OCheck Ior air leaks around tubing ioints. OExcessive undetected negative pressure OCheck Ior unattended intravenous solution administration. Management oI air embolism iI present OClamp the venous line and stop the blood pump. OPlace the patient in Trendelenberg position on the leIt side with the chest and head tilted downward to trap the air at the apex oI right ventricle away Irom the outIlow tract. OCardiorespiratory support ,Oxygen 100. OOccasionally percutaneous aspiration oI the air Ioam Irom the heart may be necessary. OOthermeasuresincludeIVDexamthsonetoreducebrainedema,Heparin/Dextrantoimprovethe microcirculation. 4. HighPositivedialysate pressure alarm OCheck to see iI drain is occluded or kinked OCheck to see iI dialysate hoses are leaking air 5.Low egative dialysate pressure alarm OCheck to see iI dialysate hoses are kinked

6.HighTemperaturealarmODetermine temperature oI dialysate (to dialyzer) in the line actually high OCheck to ensure incoming water temperature is blew 90 F 7.Low Temperature alarmODetermine temperature oI dialysateto dialyzer inthe lineis actually Low OTurn the mode selector switch to 'dialyze OAllow adequate time Ior the system to stabilize and come to proper temperature range OCheck to ensure incoming water temperature is above 40 F .High conductivity alarmOCheck to see iI water is Ilowing too slowly or turn oII OCheck Ior kink in the concentrate out line OMake sure that the systemhas had time to stabilize OAnalyze the dialysate to conIirm high conductivity at the 'to dialyzer line connection : 1.If normal. there is malfunction in the machine itself (change it 2.If high again concentrate should be changed 3.Check the conductivitv before resuming dialvsisOBe certain that the dialysate Ilow rate is proper. 9.Low Conductivity alarmOTurn the mode selector switch to 'dialyze OConnect the concentrate line to the system ODrop the concentrate line into the concentrate container OCheck Ior kinks in the 'concentrate in line OMake sure the Iilter on the 'concentrate in is clean OAllow adequate time Ior the system to stabilize OChange the concentrate container iI it is dry OII the concentrate containerhas not run dry ,a sampleoIdialysate should sent to thelaboratory Ior sodium and chloride OAnalyze the dialysate to conIirm low conductivity at drain 1.If low conductivitv is confirmed, change the concentrate bottle (recheck again 2If the conductivitv still low after changing the concentrate . a different machine should betried OBe certain that the dialysate Ilow rate is proper 10.lood Leak alarmOMake sure the blood leak detector is clean OCheck the eIIluent Ior traces oI blood O .Check the dialysate lines Ior gross blood leak Exclude 1bilirubin in dialvsate in iaundiced patient 2air bubbles in dialvsate 3dirtv sensor OII a leak conIirmed and you can not mange the cause 1reduce dialvsate compartment pressure to -50 mmHg to avoid bacterial enterv to the blood 2Dicontinue dialvsis N.B. Review the previous tips and the manual for each machine if needed Hemodialysis Procedure

Schematic representation oI dialysis system CA#AL #ASSSSA% Acuteorchronicdialysisprescriptionshouldbereviewed.evaluated.andcarriedoutaccurately toobtain themaximaleIIiciency Iordialysis. The patient's physiologic status is assessed to ascertain the necessityoIadiustinganydialysisorders. Allmachineparametersareassessedtoensurethatthe prescribed procedure is correctly implemented. The goal is to initiate and terminate the dialysis procedure saIely and comIortably with no or minimal complications. #ASAC AAD P#AC TechnicalandnursingpersonnelhaveagreatresponsibilitytoassureproperandsaIeconnections,Ilow paths, and overall adequacy and saIety oI the system. Adherence to the manuIacturer's procedure Ior rinsing is mandatory. Importance of rinsing and priming .1.Rinsing and priming the dialyzer assure adequate removal oI allergens (e.g.ethyleneoxide ) and reduction oI the incidence oI anaphylactic membrane reactions2.Microbubbles are also removed when the venous end oI the dialyzer pointed upward. Thedialyzershouldbeusedwithin5-10minutestoavoidleachingoIresidualethyleneoxideorother leachable allergens into the rinsing Iluid. Dialyzer should be rerinsed brieIly immediately prior to dialysis iI more than 10 minutes has elapsed. PA%A% OA%O#AC P#DALYSS: Weight,PulseRate,B.P.Laying&Standing Temperature,Fluidstatus,Bloodinvestigationsand Vascular access patency and Ireedom Irom inIection O%AAAC JASULA# ASS Poor vascular accessis a limiting Iactor to patient survival onhemodilysis. ThereIoregreat caremust be taken to maintain adequate vascular access. OPercutaneous venous cannula ( Femoral,Subclavian,Jugular ) Residual heparin or clot is Iirst aspirated Irom both catheter lumen Check the patency oI each lumen by irrigating with a saline Iilled syringe. Heparin loading dose is administered in the venous limb and Ilushed with saline. Initiate dialysis aIter 3 minutes OAV Iistula and graIt: (see the previous tip, Using permanent vascular access Heparin loading dose is administered in the venous needle and Ilushed with saline. Initiate dialysis aIter 3 minutes A%A%%AC DALYSS OSet the blood Ilow rate at 50 then 100 ml/minute, untill the blood Iills the blood circuit. OThePrimingIluidinthelinesanddialyzerisdisposedoItodrainuntilthebloodreachesthe venous air trap. In unstable patient the priming Iluid is usually given to the patient t maintain the blood volume. OIncreasethebloodIlowratetothedesiredlevelaIterthecircuitisIilledwithblood(150-250in acute cases). OInitiate the dialysis solution Ilow and adiust the TMP. ALA#SBlood circuit Arterial pressure Venous pressure Air detector Dialysis solution circuit Conductivity Temperature Blood leak PA%A% OA%O#AC DU#AC DALYSSPulse rate , BPevery 30 to 60minutesin chronicdialysis, but at least every 15minutes in acute dialysis, Food & Fluid intake, Complications during dialysis and any particular observations. %#AA%OA OF DALYSS a. Saline rinse: The blood is returned by pumping sterile normal saline into the arterial side until the blood isdisplaced. AIterthebubbletraptheIluidshouldbeverypalepinkincolor (toassurethatthe patient has lost the least amount of red cells. b.Saline-Airrinse: ThebloodisIorcedbypumpingasmallamountoIsalineintothearterialline,then the line is opened to allow air into the circuit to push the saline and blood. Again the Iluid entering the patient should be very pale pink in color. c.Air-Salinerinse: ItbeginswithaninIusionoIairtodisplacetheblooduntilitreachestheendoIthe dialyzer. At this point the saline is pumped into the arterial line to displace the air.At the same time theairisallowedtoescapeattheleveloIvenouschamberwhilethesalineisbeinginIusedtothe patient. It is eIIective, but air embolism is a potential risk. NB: I- Constant visual monitoring of venous line is required to avoid air infusion into the patient in b and c methods II- Hollow fiber dialvzer are rinsed bv saline rinse method because complete removal of blood bv air from tinv diameter of hollow fiber is difficult. PA%A% OA%O#AC POS%DALYSS Weight , PulseRate ,BPLaying&Standing,Temperature,BloodinvestigationsandVascular accesspatency.Allpatientsparametersandanyunusualoccurrencesshouldbedocumentedonpatient's Iile. "UPA% A# ThecareoIdialysismachineistheresponsibilityoIthestaIIand oIthebiomedicaltechnicians. Scheduled maintenance recommended by the manuIacturer should Iollowed meticulously Ior the saIe and eIIicient Iunction oI the equipment. nticoagulation for Hemodialysis Mechanism of clotting in extracorporeal circuit: Clotting oI blood in extracorporeal circuit may be initiated when blood comes intocontact with cannulas,lines, and the dialysis membranes. Steps oI clotting:1.Coating oI the circuit with plasma proteins. 2.Platelet adherence and aggregation 3.Generation oI Thromoxane A2. 4.Activation oI intrinsic coagulation cascade. 5.Thrombin Iormation and Iibrin deposition. Predisposing Iactors: 1. Reduced anti coagulant. 2. Reduced blood Ilow rate. 3. Increased whole blood hematocrit |EPO therapy| 4. Increased extracorporeal hematocrit |excessive ultraIiltration|. 5. Blood transIusion and Lipid inIusion during dialysis.. Signs oI blood clotting in the extracorporeal circuit : 1.Dark-colored blood 2.Dialyzer : Presence oI black streaks in the dialyzer OReduced residual dialyzervolume OPresence oI clots at arterial header. 3.Lines -Foaming at the drip chambers and venous trap. OClot Iormation at the drip chambers and venous trap. 4.PressureOIncreaseddiIIerence between the postpump andvenous pressure when there is clots at arterial chamber or the dialyzer. OIncreaseinpostpumpIollowedbyincreaseinvenouspressureiItheclotsaredistalto the venous chamber OIncreased venous pressure when venous needle is clotted Anticoagulants 1.Heparin a.Crude heparin b.Low molecular weight heparin 2.Antiplatelet agents a.Protaglandins PGI 2 , PGE 2 ,eporostemol and iloprost OPotent inhibitors oI platelets aggregation OLess eIIective than heparin OSide eIIects include ; hypotension ,Ilushing, headache ,nausea and vomiting b.Aspirin , NSAID , Sulphinpyrazone and Ticlopidine OAntiplatelets Counteract platelet Iactor 4 and prevent its heparin neutralizing eIIects ONot suitable to maintain anticoagulation -May be used as heparin sparing 3. Protease inhibitors|NoIomostat, Gabexate| OInhibitors Ior both coagulation/Iibrinolysis cascade and platelet aggregation. OAdequate anticoagulant eIIect and reduce bleeding complications. 4.Hirudin OIt is polypeptide thrombin inhibitor.Unlike heparin does not require coIactor to act ODoes not cause platelet stimulation or aggregation

Heparin and Heparinization

Nature of Heparin Heparinis an anionic sulIatedmucopolysaccharideoIvariablemolecular weight|8000 to 14000 d| .Low Molecular Weight Heparin Iractions |4000-6000 d| are obtained Irom crude Heparin .Heparin is strongly acidic And is neutralized by strong basic compounds such as protamine ,toluidine and quinidine . The halI liIe is about 90 minutes and the peak anticoagulant activity is reached 5-10 minutes Mechanism of action. Heparin alonedoesnot have anticoagulanteIIect. In the bloodit combinewith a protein Iraction called heparin coIactor |antithrombin III|. The complexoI Heparin -Antithrombin III preventsclotting at the three stagesoI coagulation 1-It binds and inactivate Thrombin 2- It binds and inactivate Activated Iactor X 3-It binds and inactivate Activated Iactor XI Low Molecular Weight Heparin |LMWH| inhibits coagulation Activated Iactor X , XII and kallikrin, but littleinhibitiononThrombin,IactorXandXIthereIorePTTandthrombintimeareminimally prolonged,thus reducing bleeding risk. Side eIIects : Bleeding PruritusAllergyOsteoporosisHyperlipidemia Thrombocytopenia

Monitoring clotting times during hemodialysis Several laboratory method are used: 1.Activated partial thromboplastin time |APTT or PTT| 2.Activated clotting time |ACT| 3.Lee White clotting time |LWCT| Thegoal istomaintainthePTTorACTatthebaselinevalueplus80duringdialysisandplus40 only at the end oI dialysis to minimize bleeding risk aIter withdrawal oI access needles.

Techniques of heparin administration 1.Intermittent inIusion AnintravenousloadingdoseoIheparin|25-50units/kgoIbodyweight|isgivenviathelast needleplaced,andsmallermaintenancedosesarerepeatedintermittentlythroughouttheprocedure. Clotting times are monitored at intervals and the dose is adiusted accordingly. 2.Continuous inIusion The patient is given the loading dose Iollowed by slowly inIusion oI the maintenance dose to the bloodcircuitataconstantratethroughoutthedialysis.Clottingtimesaredoneatintervalsandthe rate is adiusted accordingly. Remarks 1.In continuousinIusion theloadingdose oI heparin islower thanwithintermittent .In the Iormerthedoseisrequiredonlytoprolongtheclottingtimestothebaselineplus80whileinthelateritisrequiredtoprolongtheclottingtimesto above thebaselineplus 80. 2.ThedoseoIheparinisdependingonsensitivitytoheparinoItheindividualpatient ,heparin halI liIe and potency oI heparin preparation 3.For a patient with an average heparin halI liIe oI 1 hour, stopping heparin administration approximately 1 hour prior to the end oI dialysis . Heparinization TestPTTACTLWCT Baseline60-85 sec120-150 sec4-8 min Standard- During dialysis 120-140200-25020-30 -At end oI dialysis 85-105 170-190 9-16 Tight -During dialysis 85-105170-1909-16 -At end oI dialysis 85-105170-190 9-16

4.During heparinization tendency to bleed is potentated by uremic platelet dysIunction and by endothelial abnormalities. 3. Regional heparinization: AdministrationoIheparin'regionallyintothearteriallineblood andneutralizingitby administration oI protamin sulIate into dialyzed blood beIore returns to the patient. Protaminisstronglybasiccompoundactsbycombiningchemicallywiththestronglyacid heparin to Iorm a stable complex with no anticoagulant eIIect. DissociationoIheparin-protamincomplexmayoccurupto10hourpostdialysiscausing bleeding problem, this is called heparin rebound. Flushing ,bradycardia ,hypotension ,and dyspnea are other side eIIects oI protamin . 4.Tight heparinization: Tight or low dose heparinization is indicated Ior patient at slight to moderate risk Ior bleeding e.g. pericarditis and recent surgery Loadingdose10units/kg Iollowedbysmalladditionaldosesaccordingtothetargetclotting times.ContinuousadministrationispreIerableintightheparinizationtoavoidIluctuationinclotting during dialysis.

Hemodialysis without heparin [heparin free dialysis] : Indications In patients with high bleeding risk 1.Pericarditis2.Recentsurgerywithbleedingcomplicationsoritwillbedangerouse.g.cardiacvascular,eye, renal transplant and brain surgery 3.Blood disease ; coagulopathy , thrombocytopenia 4.Intracerebral hemorrhage 5.Any active bleeding Methods of heparin free dialysis 1.Heparin rinse ORinse the extracorporeal blood circuit with 3000 units heparin/liter OFlush the heparin containing saline with unheparinized saline or patient blood. 2.High blood Ilow rate OSet the blood Ilow rate as high as possible , 250-300 ml/minute iI it can be tolerated. 3.Saline rinse ORinse the dialyzer with 100-200 ml oI saline .Adiust the UF rate to remove the excess Iluid Patient Monitoring During Dialysis

PatientmonitoringisaseriesoIrepeatedorcontinuousobservationoIthepatient`sappearance andphysiologicstatebeIore,duringandaIterdialysisprocedure.Theseobservationsarechartedand madepartoIthepatient`spermanentrecord.TheobiectivesaretoprovideascomIortableandsaIe procedure as possible Ior the patient and to detect as early as possibleany complication during dialysis. General ObservationsMonitoring Predialysis:Weight , Pulse Rate , B.P.Laying &Standing, Temperature Monitoring DuringDialysis: Pulse Rate , BP , Food &Fluid intake Particular Observations Monitoring Postdialysis:Weight,Pulse Rate, BP Laying &Standing ,Temperature eight. The weight oI the patient is a good index oI how well , or how poorly , the patient is controlling his Iluid balancebetweendialyses.ThepreandpostdialysisweightprovidethebestindicationoItheamountoIultraIiltrationneededduring the procedure. The patient should beweighted immediately beIore and aIter eachdialysis,wearingthesamearticlesoIclothingandusingthesamescale.thepatientshouldweigh himselI or herselI daily. One should strive to keep the interdialysis weight gain below1.0 kg/day Thedryweight isthetargetpostdialvsisweightthatideallvwouldresultsinremovaltheexcessbodv fluid. The dry weight Ior each patient must be determined on trial-and-error basis. II the dry weight is set toohighthepatientwillhaveclinicalevidenceoIIluidoverload.OntheotherhandiIitsettoolowthe patient may suIIer Irom malaise ,dizziness ,weakness , cramps , and Irequent hypotension episodes. Pulse Rate. At the start oI dialysis, pulse , temperature, BP observations serve as baseline A rapid pulse may indicate lowhematocritorIluidoverload.Anincreaseinpulserateduringdialysismybeassociatedwithdecreasing blood volume Irom ultraIiltration and may occur beIore blood pressure drop. Arrhythmia may indicatesomecomplicationse.g.,cardiacinstability,electrolytedisturbance......etc.,itshouldbebrought to the physician`s attention. Temperature: High temperature suggests inIection or complicating illness. The patient should be questioned as to other symptoms The vascular access should be inspected careIully Ior evidence oI inIection, swabs and cultures shouldbecollected,andevaluationbythephysicianismandatory.Temperatureduringdialysismaybe theresultoIwarmdialysisIluid,apyrogenreactionor showeringoIthebacteriaIromtheinIected access. Blood Pressure.Bloodpressure isthepressureexertedbythebloodagainstthewallsoIthearterialbloodvesselsduring systoleanddiastoleoItheheart.It resultsIromthepumping IorceoItheheartandtheresistanceoIthe vessels. Usually BP is measured indirectly with a cuII-type sphygmomanometer. Occasionally both arms are used to complete the blood circuit, in such instance, the cuII can be wrappedaroundthe midthigh area and the stethoscope applied at the bend oI the knee. The BP obtained by this method, however, will be 20-40 mm Hg higher than arm pressure. For patients on dialysis, normal BP is largely individual matter. That is, we are interested in changes that mayoccurthaninabsolutevalues.Thepatient`sBPshouldbemonitoredevery30minutesIoranacute dialysisandevery30-60minutesIorchronicdialysis.Asystolicvaluegreaterthan 200ordiastolic greaterthan110shouldbebrought tophysician`sattention.Predialysishypertensionisusuallyvolumerelated. Loweringdialysate sodium concentration (not below 135-140mEq/L) and restrictionoI salt Iluid intake is oI great help to control predialysis hypertension. Most oI the patient are instructed not totakeantihypertensivemedicationpriortodialysis.Inseverelyhypertensivepatient,patientsbeing dialyzed in the aIternoon and those patient iI hypotension during dialysis is not a problem., they can take their antihypertensive medication saIely. Causes ,prevention ,and managementoI interdialytic hypotension were discussed previously. Food and Oral Fluid intake. OThere are several reasons Iorwatching Iood andoral Iluid intakeduringdialysis. The amountoI Iluid removed by ultraIiltrationis estimated by the net change in the weight Irom the predialysis to the postdialysis state. The quantity oI Iood or Iluid ingested should be taken into consideration inmakingthiscalculation.ApintoIIluidisequalsto halIkilogram.Althoughitispermissible Ior most patients to eat during dialysis ,iI desired ,it is best to limit this to a small meal or snack. ODigestionmaycontributetodevelopmentoIhypotensionandvomiting.Thisisdistressingand increases the risk oI aspiration as well as interIering with a smooth dialysis. OIce chips can be used as water substitute, it iseIIectivein alleviating the sensation oI thirst than water. The disadvantage oI ice is that is water, and people tend to disregard this Iact. A 200 ml oI ice chips is equivalent to 150 ml oI water. OItisnotrecommendedthattooralIluidsbegiveninlargeamountasacontrol Iorexcess ultaIiltration.SuchIluidsmayreachtheintracellularcompartmentduringdialysisandthenbe diIIicult to remove. Also, oral Iluid is always hypotonic, contributing to hyponatremia. Particular Observations. Generalcondition andresponseoIthepatientduringtheprocedure.Nausea,Vomiting,Apprehension, Shortness oI breath, Chest pain, Sweating, Pallor, Restlessness or agitation , Irritability, Itching, Flushing , Childish or Hysterical behavior, Sleepiness ,and complaints oI pain are some oI many points to be noted. Laboratorv tests Theplasmaureanitrogenandscreatininearemonitoredmonthly.Themidweek,predialysislevelis commonly Iollowed. The plasma urea level is largely determined by the amount oI protein ingested, while the plasma creatinine level depends on the muscle mass. Factors other than protein can aIIect plasma urea .II the plasma urea is higher than expected many Iactors should be excluded e.g. Increased dietary intake, Hypercatbbolicstate,GITbleeding,V.AccessRecirculation,Dehydration.OntheotherhandiIitis lowerthanexpected;Decreaseddietaryproteinintake,Increaseddialysistreatment,andLiverdiseases shouldbeexcluded.Forpatientswithhighpredialysis S.Potassiumdietcontrolandresinexchangeis necessary. OMonitoringSCalcium,SPhosphateandAlkPhophatasearehelpIulteststopreventandtreat renalbonediseaseThesevaluesareusuallycheckedmonthlypredialysis.Thetarget plasma calcium should be at the upper level oI normal and plasma phosphate should be at the lower level oI normal. LFTsareusuallycheckedmonthly,andmayunmasksilentliverdisease,especiallyHepatitisor Hemosidrosis.TheaimoImonitoringHemogram,SIron,TranIserrin,Ferritinistodetectandtreat Hematological Abnormalities in dialysis patient

FrequencyTest Monthly1-Renal proIile (Urea ,Creatinine, Electrolyte) 2-S.Calcium ,Phosphate ,Alk Phosphatase 3-LFTs(TSP-S Albumin, AST, ALT ,S Bilirubin) 4-Blood Glucose 5-Hemogram (WBCs ,Hb, PCV, MCV, PLAT.,) 6-S Iron ,TransIerrin 7-KT/V Every 3 months1-HBsAg,Anti HBsAg 2-Anti HCV 3-HIV 4-S.Aluminum Every 6 months1-S.Ferritin 2-PTH Yearly1-Skletal Survey 2-X-Ray Chest 3-ECG Complications during Hemodialysis

DAL OPLA%OAS Common Complications during Hemodialysis 1.Hypotension (20-30 oI dialyses) 2.Muscle Cramps (5-20 oI dialyses) 3.Nauseaand Vomiting (5-15oI dialyses) 4.Headache (5 oI dialyses) 5.Chest Pain (2-5 oI dialyses) 6.Back Pain (2-5oI dialyses) 7.Itching (5 oI dialyses) 8.Fever and chills (1oI dialyses) Serious complications during hemodialysis 1.Disequilibrium syndrome 2.First use syndrome 3.Arrhythmia 4.Cardiac tamponade 5.Intracranial bleeding 6.Seizures 7.Hemolysis 8.Air embolism Mechanical Complications1.Rupture dialyzer 2.Clotted dialyzer 3.Air embolism 4.High conductivity 5.Low conductivity 6.Low water pressure 7.High venous pressure 8.Abnormal arterial pressure 9.Electrical Iailure 10.Needle-site bleeding 11.Hemolysis Management of Medical and Mechanical Complications During Hemodialvsis ComplicationManagement Hypotension1.Place the patientin trendlenberg position (iI respiratory status allows). 2.A bolus oI 0.9 saline (100-250 ml) should be administered through the venous line. Alternative to 0,9 saline : O3saline 50-100 mlODextrose50 25-50 ml OHuman lbumin 20 50-100 ml OMannitol OPressor agents egg Dopamine 3.Reduce the UF rate near to zero. 4.Discontinue dialysis in severe cases Disequilibrium syndrome In mild cases : Treat the symptoms, Reduce blood Ilow rate, Hypertonic saline dextrose solution can be administered. In severe cases: Stop dialysis ,treat the seizures Supportive measures oI coma , Mechanical ventilation iI necessary, IV mannitol may be oI beneIit. ngina1.Nasal oxygen should be initiated. 2.Reduce blood Ilow rate and stop ultraIiltration. 3.Sublingual nitroglycerin iI blood pressure is maintained. 4.Sedation. 5.Treat the possible cause. 6.Dialysis with bicarbonate dialysate bath. 7.In severe cases discontinue the procedure . 8.ECG and Further investigation may be required to exclude myocardial inIarction. ir Embolism1.Clamp the venous line andstop the blood pump. 2.Place the patient in Trendelenberg position on the leIt side with the chest and head tilted downward to trap the air at the apex oI right ventricle away Irom the outIlow tract. 3.Cardiorespiratory support , Oxygen 100. 4.Occasionally percutaneous aspiration oI the air Ioam Irom the heart may be necessary 5.OthermeasuresincludeIVDexamthsonetoreducebrainedema,Heparin/Dextrantoimprovethe microcirculation. $eizures1.Discontinue dialysis. 1.Ensure airway patency 2.Collect blood sample Ior glucose, calcium, electrolyte, urea and creatinine. 3.Administration oI 5-10 mg Diazepam slowly IV. Repeat aIter 5 minute intervals, iI seizures persist, to a maximum 30 mg. 4.Give glucose IV iI hypoglycemia is suspected. 5.Give calcium gluconate IV iI hypocalcaemia is suspected. 6.Treat other electrolyte disturbance. Muscle Cramps1.Concomitant occurrence oI hypotension and cramps may respond to treatment with100mloI 0.9 saline 2.Hypertonic saline or dextrose | Leads to dilatation oI themuscle bed blood vessels restore blood volume|. *Hypertonic dextrose( 50 ml oI10 dextrose.) is preIerred Ior treating non diabetic patient to avoidthirstproduced by saline. ausea and 'omiting 1.Reduce blood Ilow rate iI acetate dialysate is being used by 30 during Iirst hour oI dialysis 2.Reduce ultraIiltration rate 3.Metoclopramide Hcl |Primperan| 10 mg IV, or Prochlorperazine |Stemetil|12.5-25 mg IV 4.Treat the cause / Use bicarbonate containing dialysate Headache1.Reduce blood Ilow rate iI acetate dialysate is being used by 30 during Iirst hour oI dialysis 2.Acetaminophen tab |Paracetamol| 500 -1000 mg PO during dialysis. 3.Treat the cause / Use bicarbonate containing dialysate tching1. Drug therapy :Antihistamines,e.g. Diphenhydramine ,Hydroxyzine Parenteral lidocaine inIusion Oral activated charcoal 2. General measures. Relievethedryskinwithtopicalemollientse.g.Lubricatingsolutions , CamphorandMenthol containing creams Switch Irom ethylene oxide to gamma ray-sterilized dialyzer. 3.Phototherapy: Ultraviolet light-B delivered in a conventional light box giving 2 treatments per week Ior 4 weeks.. 4.Control oI calcium and phosphorous metabolism: eedle-site bleeding 1.Direct pressureis the simplest andeIIectivemeasure. It should be aseptically andwithextremecare to avoidAV access occlusion. 2.Apply gelIoam to the puncture site 3.Adiust heparin dose Hemolysis1.Clamp the blood lines2.Turn the blood pump oII 3.Do not reinfuse the blood 4.Leave the needle in place 5.Draw blood Ior: Type and cross matchCBCElectrolyteTrace metals, 6.Save dialysate and blood samples Ior Iurther evaluation7.Discard the dialyzer line 8.Evaluate the problem by reviewing the Iollowing Check conductivitv Check the dialvsate temperature Look for kinks in the blood line in the pump Check dialvsate for ,Electrolvte Formaldehvde-Chlorine-Trace metal 9.Check the IV priming solution 10.Resume dialysis to prevent hyperkalemia and blood transIusioniI necessaryRuptured Dialyzer An immediate decision must be made to: 1- ReinIuse the blood (or not) 2-Change the ruptured dialyzer as quickly as possible. 3-Resume dialysis iI saIe to do so |Usuallv less than 1 of blood present in dialvsate trigger the blood leak alarm] Clotted dialyzer1.When a dialyzer clots , the dialvzer .the arterial line. the venous line may need to be replaced. 2.In clotted dialyzer without rupture , the entire dialysate circuit does not need to be set up again or recleaned 3.Correct the cause High'enous Pressure 1-Manipulate the needle and or the line. II the access is small, a tourniquet must be used, being certain the blood pump is oII..RecannulationwithnewneedleiIneeded,theoriginaloneshouldbeleItinplaceuntiltheendoIdialysis.toavoid undue bleeding as the patient is heparinized 2-Adiust the blood Ilow rate, Proper heparnization, Treat access problem, and Proper needle and needling 3-Extreme care must be exercised when dialyzing a patient with high venous pressure *This increases the baseline TMP and obligatory ultraIiltration will occur *Single-needledeviceisoccasionallyimpossibletouse,becausewithhighvenouspressure,venousreturnwillbe impaired and blood recirculation will be high. bnormal rterial Pressure 1- Manipulation oI the arterial needle is similar to that oI venous needle. In most cases the needle may have to be replaced with the same precaution as with venous needle 2-Treat the cause.3- Proper needling4-Asses the access High Conductivity 1.Evaluate the incoming water and check Ior kink the line. 2.The water pressure and Iilters should be also checked 3.Recheck the conductivity: II normal, there is malIunction in the machine itselI(change it) * II high again concentrate should be changed * Check the conductivity beIore resuming dialysis Low Conductivity 1.Change the concentrate container iI it is dry 2.II the concentrate container has not run dry, a sample oI dialysate should sent to the laboratory Ior sodium and chloride 3.Recheck the conductivity with second conductivity meter: *II low conductivity is conIirmed; change the concentrate bottle (recheck again) *II the conductivity still low aIter changing the concentrate, a diIIerent machine should betried Membrane Reactions Type A 1-Stop dialysis2-Clamp the blood lines 3-Do not reinIuse the blood4-Discard the dialyzer and the line 5-Cardiorespiratory resuscitation 6-Antihistaminic ,Steroids ,Epinephrine can be given Type B 1-Oxygen therapy 2-Treat as in angina during dialysis Disequilibrium svndrome Definition: ItisasetoIsystemic&neurologicalsymptomsandEEGIindingthatoccurduringorsoon aIter acutedialysis Pathogenesis. 1.RappidremovaloIsoluteIromtheextracellularIluid compartment results inanosmolar gradient between brain and bloodhence results in cerebral edema. 2.A Iall in pH oI spinal Iluid has been also noted to occur. Clinical manifestations : MildSevere Headache Fatigue Nausea Vomiting Muscle cramps Restlessness Hypertension Agitation ConIusion Seizures Stupor Coma

Prevention: 1.Limit the amount and rate oI dialysis. 2.UseoI high dialysate sodium levels. 3.Use bicarbonate dialysis. 4.Intavenous inIusion oI: Hypertonic dextrose Hypertonic saline Mannitol Management. In mild cases : Treat the symptoms, Reduce blood Ilow rate, Hypertonic saline or dextrose solution can be administered. In severe cases: Stop dialysis, treat the seizures Supportive measures oI coma Mechanical ventilation iI necessary, IV mannitol may be oI beneIit. NB If coma is due to disequilibrium. the patient should improve within24 hours

Intradialvtic Hvpotension Causes A-Decreased Plasma Volume : 1.High ultrIiltration rate 2.Fluctuation in the ultraIiltration rate. 3.Target dry weight set low 4.Low dialysatesodium. 5.Dialyzers with large surIace area 6.Increased blood Ilow rate. 7.Increased dialysate Ilow rate B-Decreased Compensatory Related Vaso Constriction: 1.Acetate dialysate. 2.Dialysate temperature 37-38`c. 3.Low dial ysate calcium. 4.Antihypertensive medications. 5.Biocompatible dialyzer membrane C-Cardiac Related Factors: 1.Failure to increase cardiac rate : Ingestion oI B blockers. Uremic autonomic neuropathy. Aging 2.Inability to increase cardiac output : Poor myocardial contractility due to aging. Hypertension. Atherosclerosis. Myocardial calciIication. Valve disease. Amylodosis. D-Other Causes: 1.Pericardialtemponade. 2.Myocardial inIarction. 3.Occult hemorrhage. 4.Septicemia. 5.Arrhythmia. 6.Anaphylaxis. 7.Hemolysis. 8.Air embolism. Management oI Intradialytic Hypotension A.Measures to Ameliorate : 1.AccurateevaluationoIdryweight;isthemostimportantstepinminimizingintradialytic hypotension . limit weight gain to less than 1 kg / day . 2.D