8.30 Dialyzer present

How to choose dialyzer and dialysis solution wisely? Paramat Thimachai,MD Division of Nephrology, Department of Medicine Phramongkutklao Hospital and College of Medicine

Outline • Basic Components of Dialyzers • Types of membranes • Efficiency and Flux • Dialysis solution • How to chose dialyzer and dialysis solution wisely ?

Dialyzer type • Coil dialyzer • Parallel plate dialyzer • Hollow fiber dialyzer

BASIC DIALYZER COMPONENTS

Membrane material of dialyzer Nature Reviews Nephrology volume 14, pages394–410(2018)

Cellulose vs Synthetic membrane Chemical composition Cellulosic Synthetic Structure Homogenous Asymmetrical Porosity Hydrogel Microporous Interaction with water Hydrophilic Hydrophobic Thickness Small Biocompatibility Low Large Electrical charge Mixed High Hydrautic permeability Low flux Negative High flux

Membrane Biocompatibility Biocompatible membranes Vitamin E coated dialyzers Less activation of the immune system and Cellulose or PS backbone inflammatory response • Coated with vitamin E (α- • Substituted cellulose and the synthetic tocopherol)  membranes essentially similar in • Reduce reactive oxygen biocompatibility *** Some patients can have sensitivity to certain species membrane material • Decrease inflammatory markers but No survival benefit yet

Ronco et al



Enhance dialyzer clearance development Pediatric Nephrology 2017

Qualification of dialyzer 4. Membrane surface area 5. Priming volume 1. Clearance (KoA) urea, Cr, B12 6. Sterilization 7. Internal filtration • Urea clearance ~ blood flow rate 8.Back transport • Intermediate efficiency : KoA urea 500-700 ml/min 2. Ultrafiltration coefficient (Kuf) • High Kuf : > 10 ml/hour/mmHg  risk of back filtration 3. Sieving coefficient = concentration of filtration/plasma • High Sieving coefficient Beta 2 macroglobulin : > 0.5

Evolution of Dialyzer • High Efficacy membrane • High flux membrane • High Cut off membrane • High performance membrane

Efficiency • Efficiency related to : Membrane size ( Surface Area) • Porosity • Thickness • Internal diameter of the fibers • Reduces the resistance of the more static blood layers • Design • Wavelike or crimped vs straight fibers

Flux • Flux: related to Kuf (Coefficient of ultrafiltration) volume of fluid (ml/hr) transferred across the membrane per mmHg of pressure gradient • High flux dialyzers Kuf > 15 ml/mmHg /h or B2M clearance > 20 ml/min • High flux dialyzer : pore radius ~ 3 nm • Clearance of molecular weight : < 15 kDa • Advantages of high flux: Improve middle molecule clearance • Disadvantages of high flux : Errors in TMP can cause large UF • Back filtration

Dialyzer type Characteristic Conventional High efficiency High flux KoA urea < 450 ml/min < 200 ml/min > 600-700 ml/min Variable Urea clearance <12 ml/mmHg/h > 200 ml/min Variable Kuf Variable > 15 ml/mmHg/h B2 microglobulin <10 ml/min Variable > 20 ml/min clearance KoA urea, mass transfer coefficient area, Kuf = ultrafiltration coefficient Priming volume in blood component = 60-120 ml , blood line = 100-150 ml

Evidence for Flux • Cochrane review of RCT’s • could not determine overall efficacy of high flux dialysis • Concluded may reduce CV mortality • HEMO study CV mortality in pts on HD > 3.7 yrs • MPO study survival in pts with albumin < 4 g/dL and in DM

High Cut-Off Membranes • Pore radius 5 nm • Higher molecular weight cut-off ~ 45-50 kDa  65kDa • Better B2M clearance compared to high flux dialyzers • Increase clearance of free serum light chains : Potential use in treatment of patients with multiple myeloma • Increase Albumin clearance



Characteristic Conventional High High flux efficiency KoA urea < 500 ml/min > 700 ml/min Variable Urea clearance < 200 ml/min > 200 ml/min variable Kuf <12 Variable > 15 ml/mmHg/h ml/mmHg/h Variable > 20 ml/min B2 microglobulin <10 ml/min clearance

Plasma-flux

Plasma-flux

High performance membrane (HPM) • Classification used in Japan  Hollow fiber dialyzers with 1. Excellent biocompatibility 2. Effective clearance of target solutes 3. Pore size larger than conventional hemodialysis (HD) membranes • Removal of protein-bound uremic toxins, and middle to large molecular-weight solutes, including β2-microglobulin (β2-M)

Adsorbent dialyzer and hemoperfusion

Recommended dialyzer characteristics for conducting Hemodialysis or hemodiafiltration 1. High UFC, >40ml/mmHg/hr ISO8637 2. Sieving coefficient for β2 microglobulin >0.7 3. Sieving coefficient for albumin <0.01. In OL-HDF, the loss of albumin should be <4g per session 4. High packing density of capillaries (>11,000) allowing for dialysis with Qd of 400– 500ml/min, with good performance 5. High internal resistance in haemodialysis, long dialyzers with internal capillary diameter of <200μm 6. In post-dilution OL-HDF, if functioning with limited Qb, high haematocrit, FF ∼30%, dialysers with >200μm internal capillary diameter. Prefilter pressure <700mmHg 7. Sterilisation free of ETO 8. Good biocompatibility. Recommended, free of BPA and other toxins and no adverse reactions.

Water treatment and dialysate แนวทางเตรยี มนา้ํ บรสิ ทุ ธิ์ สมาคมโรคไต พศ. 2559

Dialysate fluid Sodium Pre-dialysis Serum Dialysate Keep serum 136-138 mEq/L  140 mEq/L Normal Na ( difference 2 mEq/L) Intradialytic hypotension sodium profile Normal K  0, 1-2 hours Potassium K> 7 mEq/L 2 mEq/L Normal Ca K >5.5 mEq/L 3 mEq/L balance K< 4 mEq/L or Heart 22-26 mEq/L disease, on Digitalis 2.5 – 3 mEq/L 3.5 mEq/L Calcium 8-10 mg/dL 34-36 mEq/L Intradialytic hypotension 30-32 mEq/L Bicarbornate 18-24 mEq/L > 28 mEq/L

How to chose dialyzer and dialysis solution wisely ? • AKI with uremic symptom  disequilibrium syndrome !!! • ESRD on chronic hemodialysis  for increase adequacy • Light chain deposition disease  remove free light chain • Plasmapheresis  remove immunoglobulin • Severe sepsis and high inflammatory cytokine  remove cytokine • Liver failure with severe jaundice  remove bilirubin • AKI due to toxic substance  remove toxic substance

Conclusions • Most dialyzers currently available are high efficiency & have similar clearance performance • High flux dialyzers have some advantages and required for delivering hemodiafiltration • Every unit must have options for patients with possible sensitivity to certain dialyzer membrane • Have choice of two different membrane material

Thank you