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Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

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Page 1: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Hemodialysis Adequacy

Lutfi Alkorbi MDKing Faisal Specialist Hospital

Riyadh Saudi Arabia

Page 2: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Global dialysis population

Page 3: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Cardiovascular mortality in general population VS ESRD patients

Page 4: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Mortality in Hemodialysis Patients in Europe, Japan, and the United States

DOPPS 2006

Page 5: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Dialysis adequacy and death

The effect of dialysis dose on survival

Page 6: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

First Randomised Controlled Trial In Dialysis

• The National Cooperative Dialysis Study (NCDS) was the first multicentric, randomized and controlled trial to investigate the impact of dialysis dose on patients' outcome. 160 patients were randomized to two different urea time‐averaged concentrations (TAC; 100 vs 50 mg/dl) and to two different treatment times (2.5–3.5 vs 4.5–5.5 h) and followed‐up for 6 months.

NCDS 1980

Page 7: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

First Randomised Controlled Trial In Dialysis

NCDS 1980

Predialysis urea 38 vs 26 mmol. Dialysis 2.5-35h vs 4.5-5 h

high kt/v and long dialysis

high kt/v and short

dialysis

low kt/v and long dialysis

low kt/v and short dialysis

Page 8: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Secondary analysis of NCDS

• A quantification of dialysis dose using spKt/V was first proposed by Gotch in a secondary analysis of NCDS data. In his analysis, probability of dialysis failure was higher for Kt/V ≤0.8 and abruptly decreased for Kt/V >0.9.

Page 9: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Higher Kt/V has better outcome

Gotch FA,Sargent Kidney Int 1985;28:526

Kt/v=1.2

Page 10: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

NCDS Conclusion

• Thus, according to NCDS patient morbidity and treatment failure are related to the dialysis dose

Page 11: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Why Should We Measure Dialysis Dose?

There is a correlation between delivered dose of hemodialysis and patient morbidity and mortality

Clinical symptoms are not reliable

Page 12: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Increasing dialysis dose improved survival

dialysis dose

Kidney Int 1996; 50:550

Page 13: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Measures of dialysis adequacy

• SpKt/V

• eKt/V

• StdKt/V

• URR

Page 14: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Hemodialysis Dose Measurement

Kt/V K= dialyzer urea clearance L/h

t = dialysis session length hr

v = distribution volume of urea L

URR

Page 15: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Urea reduction Ratio(URR)

URR = 100 x (1-Ct/Co)

Ct = postdialysis BUN

Co = predialysis BUN

Page 16: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Urea Reduction Volume (URR)

Simple Prediction of mortality

Limitation:

Does not account for the contribution of UF to dialysis dose

Kt/V=1.1 (UF=0)

Kt/v = 1.35 (UF=10%BW)URR=65

Page 17: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

URR & Kt/V

Page 18: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Hemodialysis Dose Measurement

• The preferred method is by formal kinetic urea modeling

K/DOQI 2006

Page 19: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Kt/V

Computerized softwareMathematical logarithm Kt/v = -Ln (R-0.008t)+(4-3.5xR) x UF

WLn = natural logarithmR = postdialysis BUN

predialysis BUN UF = Ultrafiltration volume in litersW = Postdialysis weight in kg

Page 20: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

BUN Sampling

Predialysis Postdialysis Immediate predialysis Slow flow/stop pump

Page 21: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Urea Rebound

Organs with low blood flow (skin, bone, muscles) may serve as reservoir for urea 70% of TBW is contained in organs that receive only 20% of CO

So: during HD, there is loss of urea from well perfused areas, this result in in BUN over 60 minutes post dialysis.

Page 22: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Post Dialysis BUN Sampling

Avoid 2 rebound:

Early (<3min post dialysis) Access recirculation,begin immediately post

hemodialysis and rebound in 20 seconds Cardiopulmonary recirculation, begin 20 seconds post

hemodialysis and is completed in 2-3 minutes after slowing or stopping the blood pump.

Late (>3 min) Completed within 30-60 minutes due to flow-volume

disequilibrium.

Page 23: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Urea Rebound

65% rebound ( >50% is AR,15%CP,31% D)

Page 24: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Single-Compartment Fixed VolumeSolute Kinetic Mode

Page 25: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Single-Pool vs Double-Pool

Single-pool

Does not account for urea transfer between fluid compartments

With dialyzer clearance, urea removed from extracellular compartment can exceed transfer from intracellular compartment

Urea rebound (30-60 min)

So: Dialysis dose will be overestimated if this urea pool is large (underestimated of true V)

Page 26: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Two-Compartment Variable VolumeSolute Kinetic Model

Page 27: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Equilibrated Kt/V

eKt/v is 0.2 units less than single-pool kt/v, but it can be as great 0.6 unit less.

For most patient, urea rebound is nearly complete in 15 minutes after hemodialysis but for minority, it may require up to 50-60 minutes

The degree of rebound is high in small patient• eKt/V= spKt/V - 0.6 x (spKt/V) / t + 0.03 (for arterial

access) • eKt/V= spKt/V - 0.47 x (spKt/V) / t + 0.02 (for venous

access)

Page 28: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Minimum dialysis dose

• SpKt/V > 1.2 US

• eKt/V > 1.2 Europe

• StdKt/V 2.14

Page 29: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Daugirdas Formula

Page 30: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Daugirdas Formula

Page 31: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Prescribed vs. delivered Kt/V

Prescribed Kt/V is a computerized estimation of what the patients Kt/V would be, based on the prescription

• Delivered Kt/V is actual results based onhow the patient really dialyzed the day thekinetic labs were drawn

Page 32: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 33: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Discrepancies Between Delivered and Prescribed Dialysis Dose

Delivered less than the prescribed: Low blood flow Inadequate dialyzer performance Low dialysate flow Dialysis machine programmed incorrectly Hemodialysis ended prematurely The predialysis BUN was drained after

initiation of hemodialysis Access recirculation

Page 34: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Discrepancies Between Delivered and Prescribed Dialysis Dose

Delivered Dose More than the Prescribed:

Postdialysis BUN was drained from venous bloodline

The post dialysis BUN was diluted with saline

Small (V)

Page 35: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Low kt/v

Page 36: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

How to improve clearance

• Blood flow

• Dialysate flow

• Dialyzer

• Duration

• frequency

Page 37: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Blood flow and Clearance

Page 38: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Blood flow and Clearance

Page 39: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Dialysate flow and clearance

Page 40: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

The HEMO Study (2002)

Page 41: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

The HEMO Study (2002)

Standard dose group

• SpKt/V 1.3

• eKt/V 1.16

• URR 66.3

• Dialysis T 190 min

High dose group

• SpKt/V 1.7

• eKt/V 1.53

• URR 75.2

• Dialysis T 219 min

Page 42: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

The HEMO Study (2002)

EKNOYAN et al N Engl j Med .2002;347:2010

Page 43: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Optimal Dialysis

Anemia management

Good nutritionBP control

Adequate solute

removal

Fluid and electrolytes hemostasis

BMDmanagement

Dialysisadequacy

Page 44: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Optimal Dialysis

Anemia management

Good nutritionBP control

Adequate solute

removal

Fluid and electrolytes hemostasis

BMDmanagement

Dialysisadequacy

Kt/v

Page 45: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Filters

Efficiency and Flux• Efficiency: ability to achieve large small solute clearance withhigh blood flows (all filters are high efficiency these days)• Flux: ability to achieve high middle molecule clearance andultrafiltration rate (determined by the average pore size)

Diffusion and Convection• Diffusion: solutes move by diffusion between blocks of fluidseparated by the membrane• Convection: solutes move en mass with a block of fluid acrossthe membrane (more effective for moving large molecules)

Page 46: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

The HEMO Study (2002)

EKNOYAN et al N Engl j Med.2002 ;347:2010

Page 47: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

The MPO Study (2009)

Page 48: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Standard Kt/V

Page 49: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Standard Kt/Vwhy Hemo study is negative ?

Page 50: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 51: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

FHN

Page 52: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 53: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 54: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Better survival with long dialysis

UpToDate

Page 55: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Residual renal function

Page 56: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Residual renal function

Page 57: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

Time is important

Page 58: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 59: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia
Page 60: Hemodialysis Adequacy Lutfi Alkorbi MD King Faisal Specialist Hospital Riyadh Saudi Arabia

What about hemodiafiltration ?