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RENAL REPLACEMENT THERAPY part2.pptx
This document discusses various topics related to renal replacement therapy including: 1. Types of renal replacement therapy such as hemodialysis, peritoneal dialysis, and renal transplantation. 2. Principles of dialysis including diffusion, convection, and regional citrate anticoagulation. 3. Components of home hemodialysis including the dialyzer, composition of dialysate, and blood delivery system. 4. Factors that influence dialysis outcomes such as patient characteristics, comorbidities, nutrition, inflammation, and dialysis treatment factors.
RENAL REPLACEMENT THERAPY part2.pptx
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- 2. THE TOPIC WILL BEDISCUSSED IN THE FOLLOWING SUB-HEADINGS: TYPES OF RRT AND PRINCIPLES VASCULAR ACCESS FOR DIALYTIC THERAPIES HEMODIALYSIS – PRINCIPLES AND TECHNIQUES HEMODIALYSIS – OUTCOMES AND ADEQUACY ACUTE COMPLICATIONS DURING HD DIALYTIC THERAPIES IN DRUG OVERDOSE RENAL TRANSPLANTATION
- 3. Dialysis options : HEMODIALYSIS INCENTER HD (3 TIMES/WEEK) HOME HD PERITONEAL DIALYSIS MANUAL (CAPD) CYCLER (CCPD)
- 4. EARLY VACCINATION FORHEPATITIS B- Too often forgotten: Patients with ESRD have decrease response to vaccination After Hepatitis B vaccination in ESRD patients : 50-60% develop antibodies compared to >90% in patients without renal failure Have lower titers Have protective levels for shorter duration
- 5. PRINCIPLES FOR DIALYSIS DIFFUSION: • Passive movement of solutes across a semi-permeable membrane down concentration gradient. • Good for small molecules CONVECTION : • Solute + fluid removal across a semi-permeable membrane down a pressure gradient (solvent drag) • Good for removal of fluid and medium sized molecules •Maximised by using replacement fluids
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- 8. PRINCIPLES FOR DIALYSIS HEMODIALYSIS: • Dialysate flows countercurrent to blood flow • Urea , creatinine, potassium move from blood to dialysate • Calcium, bicarbonate move from dialysate to blood HEMOFILTRATION : • Uses hydrostatic pressure gradient to induce filtration/ convection plasma water + solutes across membranes HDF
- 9. HOME DIALYSIS: Components : •Dialyser • Composition of the dialysate • Blood delivery system DIALYSER : • Hollow fiber dialyser – bundles of capillary tubes through which blood circulates and the dialysate travels on the outside • Circulate in opposite direction
- 10. DIALYSIS MEMBRANE • It canbe synthetic or biological • Cellulose - has low flux poor in removing middle MW molecules more complement and leucocyte activation • Synthetic : High flux membranes Made up of polyamides / polysulphones Allows removal of middle MW molecules
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- 12. REGIONAL CITRATE ANTICOAGULATION : Heparin - It is alternative to heparin. Sodium citrate is infused into the circuit pre- filter which chelates calcium and inhibits clot formation.
- 13. CONTINUOUS RENAL REPLACEMENT THERAPY: Dialyse patients more physiologically Avoids accumulation of waste products Avoids the rapid shifts in volume and osmolarity Avoids disadvantages of PD
- 14. CONTINUOUS RENAL REPLACEMENT THERAPY: ADVANTAGES Precise volume control Suitable for hemodynamically unstable patients Very effective control of uremia / hyperkalemi/ metabolic acidosis Safer for patients with TBI/ CVA Improve nutritional support DISADVANTAGES Expensive Anticoagulation Hypothermia Severe depletion of electrolytes – K/ PO4 Complications of line insertion/ sepsis/ line disconnection
- 15. REPLACEMENT FLUIDS • Usedto increase the amount of convective solute removal in CRRT • Replacement fluids do not replace anything • 0.9% saline • Can be pre/ post filter
- 16. COMPARISON OF PREAND POST DILUTION : PRE - FILTER Increase filter life Increase convective transport Reduced solute clearance Some of delivered replacement fluid lost by hemofiltraton Lower anticoagulation requirements Higher UF required POST - FILTER No solute dilution, improved diffusion and solute clearance Increased hemoconcentration Higher delivered dose of hemofiltration
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- 19. SLOW CONTINUOUS ULTRAFILTRATION (SCUF): •Removal of ultrafiltrates at low rates ( without administration of replacement solution/ dialysate) • Purpose – prevent or treat volume overload ( No waste product removal/ acidosis) • Primary indication – volume overload • Mechanism – ultrafiltration •The amount of fluid in the effluent bag = amount of fluid removed from patient • Removal rates 100 ml/hour
- 20. LET’S REVISE.. Primarytherapeutic goal – safe management of fluid Primary indication Principle Characterestics Blood flow – 80-200 ml/min Ultrafilration – 20- 100ml/hour No dialysate/ replacement fluid
- 21. CONTINUOUS VENOVENOUS HEMOFILTRATION: An effective method of solute removal and indicated in uremia/ severe acidosis/ electrolyte imbalance with or without fluid overload Good at removal of large molecules Principle used – convection A substitution solution used pH is affected with the buffer in the substitution solution Solutes can be removed in large quantities while maintaining fluid balance Fluid in effluent bag No dialysate used
- 22. LET’S REVISE.. Primarytherapeutic goal – solute removal plus safe fluid management Primary Indications Principle used Characteristics CVVH dosage – Blood flow – 80-200 ml/min Ultrafiltration – 20-100 ml/hour Replacement fluid – 30 ml/kg/hour ( divided in pre and post filter)
- 23. CONTINUOUS VENO VENOUSHEMODIALYSIS • Effective for removal of small to medium sized solutes • Diffusion • No replacement fluid. Dialysate is run on opposite direction • Fluid in the effluent bag •Continuous diffusive removal of waste products ( small molecules) utilising dialysate • pH also affected due to the buffer content
- 24. LET’S REVISE.. Primarytherapeutic goal : solute removal and safe management of fluid volume Indications Principle Characteristics Blood flow – 80-200 ml/min Ultrafiltration – 20-100 ml/hour Anticoagulation Dialysate : 45ml/kg/hour No replacement fluid
- 25. CONTINUOUS VENO-VENOUS HEMODIAFILTRATION : The most flexible of all – combines diffusion and convection The use of replacement fluid allows adequate solute removal even with zero or positive net fluid balance for the patient Amount of fluid in the effluent bag Dialysate on the opposite side of the filter and replacement fluid either before or after filter Continuous small and large molecules removal pH also changed by the buffer
- 26. LET’S REVISE.. Primarytherapeutic goal : solute removal and safe fluid management Indications Principle used Characteristics Effective in removing small, medium and large molecules Dialysate and replacement fluid dosage : 45 ml/kg/hour : ½ as dialysate and ½ as replacement fluid I divided into pre and post filter)
- 27. PERITONEAL DIALYSIS: Peritonealcavity is used as a container for 2-2.5 L glucose containing dialysate- exchanged 4-5 times daily Peritoneal membranes with capillaries Principle – diffusion and osmosis Waste products diffuse out and excess body fluid removed by osmosis C/I – large diaphragmatic defects/ adhesions/ IBD
- 28. ADVANTAGES : Slow,continuous, physiologic mode of removal of small solutes ; no need of vascular access; less catabolism; RRF is better preserved.
- 29. THREE PORE MODEL: Major principles – diffusion (concentration gradient) and convection ( filtration/UF) – osmotic / hydrostatic pressure gradient Smallest pores - aquaporins water permeable only; crystalloid osmotic pressure Small pores in middle – solutes – diffusion/ water – convection Large pores – macromolecules by convection
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- 33. INDICATIONS: Acidemia (pH,7.1) Electrolytes –Hyperkalemia / severe dyselectrolytemia Ingestion of toxins/ drugs Overload/ oliguria ( UOP< 200 ml/ 12 hour) Uremia Uremic encephalopathy Uremic pericarditis Uremic neuromyopathy
- 34. DIALYSABLE OR NOT: DIALYSABLE Barbiturates Lithium Alcohols, aminoglycosides Salicylates Theophyllin Penicillins Carbapenems, cephalosporins NON-DIALYSABLE Digoxin TCA Phenytoin Benzodiazepines Beta blockers Metformin
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- 38. BLOOD CIRCUIT FOR HEMODIALYSIS A.The blood circuit B. The pressure profiles in the blood circuit with an arterio- venous fistula as the vascular access
- 42. HEMODIALYSIS – OUTCOMESAND ADEQUACY : FACTORS RELATED TO DIALYSIS OUTCOMES FACTORS WAYS TO ADDRESS A) PATIENT CHARACTERESTICS: • Age/ gender/ race • Body size None Target BMI >23kg/m2 ; treat malnutrition B) COMORBIDITIES : • Diabetes mellitus • HTN • CHF • PVD Prevent Hypoglycemia; Target HbA1C < 7.5 Decrease dietary salt, avoid positive sodium balance Optimise fluid status by post dialysis target reduction Aspirin, lower lipids, manage hyperphosphatemia
- 43. FACTORS WAYS TOADDRESS • Arrhythmias • Physical activity • Transplant eligibility Avoid hyperkalemia / hypokalemia; zero K – dialysate bath not used Nephrogenic rehabilitation programme; exercise during dialysis Living donor transplantation C) ANEMIA • Hemoglobin concentration • EPO resistance Target Hb level 10-11 g/dl Target TSAT>25% ; identify and treat source of inflammation D) CKD-BMD • PTH • FGF- 23 • Hyperphosphatemia Lower phosphate levels Lower phosphate levels Dietary restriction/ phosphate binders/dialysis
- 44. FACTORS WAYS TOADDRESS E) NUTRITION AND INFLAMMATION • Inflammation • Low serum albumin/ PEM • Fluid overload • Vascular access • B2 microglobulin Ultrapure dialysate, avoid central venous catheter and graft access -Do – -Define post HD target weight -Grafts and fistula preferred -Increase middle molecule clearance, HDF F) DIALYSIS TREATMENT FACTORS: • Session length • Frequency • Dialysis dose •Dialysis modality More important than urea clearance once min Kt/V has achieved 4-7 sessions per week Target Kt/V .1.3; URR > 65% per treatment High efficiency on-line HDF
- 45. FACTORS WAYS TOADDRESS • HD membrane biocompatibility • HD membrane types • Dialysate quality • Dialysate composition • Acidosis • Intradialytic hemodynamic stability Biocompatible High – flux membranes Ultrapure dialysate Individualised Target pre HD bicarbonate > 22 mmol/L Thermoneutral dialysis ; avoid high UFR
- 46. ADEQUACY OF DIALYSISDOSE UREMIC TOXINS : Retention in the body of compounds normally metabolised by healthy kidneys Reduced clearance of urea / increased b2 microglobulin Increased mortality Free water soluble LMW solutes • Guanidnes- creatinine • Peptides • Polyols • Purines/ pyrimidines/ ribonucleosides • Others Protein bound solutes • AGE • Hippurate/ Indoles/ Phenols • Polyamines Middle molecules • Cytokines – IL1B/ IL-6/ TNF- a • Peptides – cystatin C/ B2 microglobulin • Others
- 47. ASSESSMENT OFDIALYSIS DOSE: Adequacy – refers to delivery of a treatment dose that sufficient to promote optimal long term outcome. Intradialytic urea kinetics : inter compartmental urea distribution is delayed. Urea in blood < urea in tissue.
- 48. UREA REDUCTIONRATIO : • URR(%) = (1-Ct/Co) * 100% • Does not takes in to account intra dialytic urea generation and convective urea removal by ultrafiltration • A minimum URR of 65-70% SINGLE-POOL Kt/V (sp Kt/V) : • K = dialyser blood water urea clearance, t = time, V = distribution volume of urea • Kt/V = 1 implies that volume of plasma cleared of urea during a dialysis session is equal to urea distribution volume.
- 49. WEEKLY STANDARD KT/V: •Total urea mass removed per time unit decreases with increasing dialysis treatment time and dose • Doubling of Kt/V from 1 to 2 per session , does not double the total urea mass removed, but increased by about 24 % only
- 51. RECOMMENDATIONS FOR DIALYSISDOSE ADEQUACY: Current European Best Practice guidelines : Dialysis delivered at least 3 times/ week and total duration at least 12 hours / week In anuric patients, target eKt/V should be at least 1.2 For patients with renal function, weekly dialysis dose should be at least equivalent to an std – Kt/V of 2.0
- 52. OTHER DIALYTIC FACTORS– MIDDLE MOLECULE REMOVAL High flux dialysers remove larger amounts of middle molecules due to higher membrane porosity Convective dialysis strategies ( HDF) are more effective Serum B2 microglobulin – a surrogate marker for middle molecule Use of synthetic high flux membranes to reduce CV risk and improve anemia
- 53. ACUTE COMPLICATIONS DURING HEMODIALYSIS CARDIOVASCULAR Intradialytichypotension/ hypertension, arrhythmias, sudden death, pericarditis, dialysis steal syndrome NEUROMUSCULAR Muscle cramps, dialysis disequilibrium syndrome, restless leg syndrome, seizures, headache HEMATOLOGIC Complement activation and neutropenia, Intradialytic hemolysis, hemorrhage, thrombocytopenia PULMONARY Dialysis associated hypoxemia TECHNICAL Air embolism, Hypernatremia, hyponatremia, metabolic acidosis/ alkalosis, blood loss, clotting
- 54. INTRA-DIALYTIC HYPOTENSION: 10-30% ;can lead to myocardial ischemia, cardiac arrhythmias, thrombosis, LOC, seizures, death May induce more renal ischemia – independent risk factor for mortality Relative intravascular volume depletion Position patient in Trendelenburg position , stop UF, infusing bolus (NS) High suspicion for cardiac ischemia – trop T, ECG Recurrent/ unexplained episodes - ECHO Preventive strategies - conventional/ midodrine/ cooling of dialysate
- 56. INTRA DIALYTIC HYPERTENSION 8-30% ; increased CV mortality and death Dialysis – refractory hypertension ( ↑ RAAS activity) EPO/ESA associated with new onset HTN ; increased endothelin-1 High sodium dialysate – improves intravascular filling, but increase thirst/ weight gain Sodium modeling – 150 mmol/L– 138 mmol/L Other mechs - ↑ SNS activity, dialytic removal of drugs ( ACEI/ B-blockers) SBP > 180 mmHg = clonidine / captopril DRIP trial – optimal control of BP achieved via volume control
- 57. CARDIAC ARRHYTHMIAS : • LVH/Congestive cardiomyopathy/ uremic pericarditis/ conduction system calcifications/ silent MI • Constant alterations in fluid , electrolytes and acid base homeostasis • QTc dispersion is prolonged after HD and is a prognostic indicator •Preventive – use of bicarbonate dialysate / Na/K/ Ca levels •Zero potassium dialysate avoided (digoxin)
- 58. SUDDEN CARDIAC DEATH: More common in elderly, DM, using central venous catheters 80% is due to VF Hyperkalemia – Profound generalised muscle weakness may be a warning sign Technical errors – air embolism / unsafe dialysate
- 59. CLINICAL • Hand numbness/pain/ weakness – DM / PAD patients • Coolness of distal arm ( MC in upper arm) • Diminished pulses, acrocyanosis, gangrene D/D • Dialysis associated cramps • Polyneurupathy ( DM/ uremia) , entrapment neuropathy (Ab2M amyloid) • Reflex sympathetic dystrophy, calciphylaxis • Evaluation of steal severity – pulse oximetry / plethysmography/ doppler/ angio MANAGE MENT •Symptomatic (gloves) • Surgical with preservation of vascular access – banding to reduce flow / DRIL •Surgical with loss of vascular access - ligation DIALYSIS ASSOCIATED VASCULAR STEAL SYNDROME :
- 60. Dialysis disequilibrium syndrome: Risk factors – young age, severe uremia, rapid and marked intra-dialytic falls in urea at initiation, low dialysate sodium Restlessness/ headache/ nausea/ vomiting/ blurred vision / HT . Timing Reverse urea theory – cerebral edema ; i/c accumulation of inositol/ glutamine/ glutamate Prevention – use of HCO3 dialysate, sodium modeling, stepped initiation (Target urea reduction 30%)
- 62. HEMATOLOGIC COMPLICATIONS COMPLEMENTACTIVATION AND NEUTROPENIA – free OH groups in cellulose dialysers – activation of alternative pathways – increased adherence of neutrophils to endothelium INTRADIALYTIC HEMOLYSIS – grossly translucent hemolysed blood observed in the tubings. Nausea/ vomiting/ hypotension. Failed oxygen therapy. HEMORRHAGE – Spontaneous bleed at GI/ subdural/ pericardial/ pleural . Reversal of uremic platelet dysfunction by ESA ( Hct>30%)/ Estrogens /DDAVP/ cryoprecipitate THROMBOCYTOPENIA
- 64. TECHNICAL : AIREMBOLISM Most vulnerable source – pre-pump tubing segment C/f depends on the volume , site and speed of air entry Sitting position – venous emboli in cerebral circulation – acute onset seizures/ coma Supine position – air trapped in RV, interfere with CO, obstructive shock Dissemination in pulmonary circ – dyspnea, dry cough, respiratory arrest, cerebral embolism
- 66. DIALYSIS REACTIONS : ANAPHYLACTICAND ANAPHYLACTOID REACTIONS: burning heat/ dyspnea/ chest tightness/ angioedema/ laryngeal edema/ paresthesia/ rhinorrhea/ lacrymation/ flushing FIRST USE REACTIONS – ETO REUSE REACTIONS – Disinfectants AN69 dialysers – bind to factor XII -- ↑ kallikrein and bradykinin PYROGENIC REACTIONS- Contaminated water/ bicarbonate dialysate/ infected cannula - ↑ cytokines Synthetic High flux dialysers have thick wall – adsorptive for endotoxins - preferred
- 67. DEVELOPMENT AND PREVENTIONOF DIALYSIS REACTIONS
- 68. DIALYTIC THERAPIES INDRUG OVERDOSE AND POISONING:
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