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Clinical Application

End Module

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  1. Gauge your confidence in Hemodialysis Kinetics
  2. Test your knowledge with a 5-question quiz
  3. Provide feedback on the module

Clinical Application

Case 3: Access Flow

Poor access flow is a big problem!

55 year old Caucasian male with history of diabetes, hypertension, coronary artery disease, and end stage renal disease secondary to diabetic nephropathy is on hemodialysis three times a week via a dialysis catheter due to previously failed fistulas. His catheter is malfunctioning and providing a Qb of 200ml/min for the last 2 treatments. You are his rounding nephrologist. You schedule him for a catheter exchange through interventional radiology but patient refuses to go any sooner than the following week as he is “tired of all these procedures.” His current dialysis prescription is as follows: Dialyzer D-flux 180 (KoA 1000ml/min), Qd-500ml/min, and a current Qb of 200ml/min with an EDW of 70kg. The renal fellow in the unit is worried about low urea clearance given poor access blood flow and decides that until the catheter is exchanged, he will change him to a larger dialyzer (D-250) with a KoA of 1600ml/min.

KT/V

What is the goal Kt/V?

  • This applies to conventional intermittent 3 times a week hemodialysis
    • Per KDOQI 2006 guidelines:  For patients with minimal residual renal function (<2ml/min per 1.73m2)
      • Minimally adequate dose should be a spKt/V of 1.2
      • Target recommended dose should be a spKt/V of 1.4 (or eKT/V of 1.2)
  • There is a lack of randomized studies to support the minimum dialysis dose of spKt/V ≥1.2.
  • However, retrospective studies suggest that a Kt/V <1.0 is associated with poor outcomes and that a Kt/V ≥1.2 is associated with better survival123.
  • The HEMO study4 showed that targeting a spKt/V higher than 1.4 did not improve survival or reduce hospitalization rates over 2.8 years.
CLINICAL PEARLS:

  • Based on large retrospective studies, a Kt/V <1.0 is associated with poor outcomes. Clinical practice guidelines, therefore, recommend a minimum delivered spKt/V of 1.2.
  • Delivered Kt/V is often lower than the prescribed Kt/V. This could be related to multiple reasons such as interrupted treatment due to machine alarms, access recirculation, blood or dialysate pump calibration errors that leads to decreased delivered Qb or Qd etc.
  • Therefore, to achieve a delivered spKt/V of 1.2, a target spKt/V of 1.4 is recommended. This equates to an eKt/V of 1.2

Sources:

  1. Owen WF Jr, Lew NL, Liu Y, et al. The urea reduction ratio and serum albumin concentration as predictors of mortality in patients undergoing hemodialysis. N Engl J Med. 1993;329(14):1001.
  2. Gotch FA, Levin NW, Port FK et al. Clinical outcome relative to the dose of dialysis is not what you think: the fallacy of the mean. Am J Kidney Dis. 1997;30(1):1.
  3. Held PJ, Port FK, Wolfe RA et al. The dose of hemodialysis and patient mortality. Kidney Int. 1996;50(2):550.
  4. Eknoyan G, Beck, GJ Cheung AK, et al. Effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med 2002; 347:2010. Hemodialysis study (HEMO)
KT/V

Kt/Vurea

As you go through this section of the module consider the following scenario:

67 year old African American male with history of diabetes, hypertension, coronary artery disease, and end stage renal disease secondary to diabetic nephropathy is on hemodialysis three times a week for 4 hours via a left arm brachiocephalic AV fistula. You are the rounding nephrologist in the dialysis unit and a concerned nurse reports that the patient’s most recent Kt/V is 1.0 down from previous levels of 1.4-1.6.

  1. What is Kt/Vurea?
  2. How do we measure Kt/V?
  3. What is the goal Kt/V?
  4. Why do we care about Kt/V?
  5. Troubleshooting a drop in Kt/V
  6. What are the limitations of Kt/V?
  7. Playground! Play around with variations of Qb (access blood flow rate), Qd (dialysate flow rate) and KoA to see  how it impacts K and Kt/V
    1. Playground Debrief
KT/V

Troubleshooting Low Kt/V

When Kt/V drops:

  • 40% of the cases occur due to decreased dialysis time or inadequate dialyzer blood flow (Qb)
  • 25% of cases are due to significant access recirculation

Troubleshooting:

  • Repeat measurement to confirm the drop using standardized measurement technique as described in the video “How to measure Kt/V in the HD unit”
  • Confirm accuracy of post BUN measurement
  • Confirm adequate Qb and time on dialysis
  • Check access integrity
  • Optimize Qb and Treatment time, resolve access issues
  • Use a higher efficiency dialyzer (higher KoA)
  • Can increase dialysate flow (Qd) although gain above 800ml/min is minimal
Clinical Application

Case 7: Dialysis Related Amyloidosis

“Ouch my wrist hurts.” Your nephrologist may be able to help.

You see an 82 year old African American male with history of ESRD secondary to polycystic kidney disease, who has been on hemodialysis for the last 12 years via a left brachiocephalic AVF. He is otherwise in surprisingly good health and very functional. While you are rounding in the dialysis unit, he tells you that he has been having left shoulder and left wrist pain and was told that he may have carpal tunnel syndrome in his left wrist. You are concerned that he may be developing dialysis related amyloidosis.

Clinical Application

Case 6: Access Recirculation

Round and round we go! A case of access recirculation.

You see a 72 year Asian male with history of diabetes, hypertension, and ESRD on HD via a left radio-cephalic AVF while rounding in your dialysis unit. His dialysis Rx is a dialyzer D flux 250, Qb of 400ml/min, Qd- 600 ml/min for a duration of 4 hours. His Kt/V on three times a week hemodialysis has ranged between 1.6-1.8. Your dialysis unit nurse reports that most recently checked Kt/V has dropped down to 1.0 confirmed on 2 different checks. He has been compliant with his dialysis treatments and has completed the full 4 hours as prescribed. Patient feels fine. His physical exam is unremarkable with blood pressures ranging between 130-150 systolic and trace edema.

Clinical Application

Case 5: Dialysis Disequilibrium Syndrome

 Lets slow things down! A patient at risk of dialysis disequilibrium syndrome

58 year old Caucasian female with history of systemic lupus erythematosus, hypertension, stroke, alcoholic cirrhosis and chronic kidney stage 5 is being initiated on hemodialysis for worsening uremic symptoms (worsening nausea, vomiting and headaches over the past couple of months) via a left arm brachiocephalic AV fistula. Her predialysis laboratory data is as follows: BUN- 140mg/dl; creatinine- 8.0; Serum K- 5.2meq/l; serum bicarbonate-12meq/l. Serum Na-135meq/l.

Choose the best dialysis Rx for this patient for his first hemodialysis treatment.

Clinical Application

Case 4: Dialyzer Size

Is a bigger dialyzer, a better dialyzer?

You are the Medical director of a dialysis unit. A dialyzer manufacturing company is trying to sell you high efficiency dialyzers with a KoA of 2000ml/min. You are currently using dialyzers with a KoA of 1000ml/min.