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Effect of Varied Dialysate Bicarbonate Levels on Phosphate and Potassium Removal

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT01930370
Recruitment Status : Completed
First Posted : August 28, 2013
Last Update Posted : May 28, 2015
Sponsor:
Information provided by (Responsible Party):
Elizabeth Harvey, The Hospital for Sick Children

Brief Summary:
Modeling of bicarbonate within the dialysate fluid, specifically a lower than standard concentration has been suggested in facilitating the removal of phosphate and potassium. To test this hypothesis, the study will use a cross-over study design to evaluate phosphate and potassium removal during dialysis by altering bicarbonate concentration in dialysis fluid (i.e. high bicarbonate, standard bicarbonate washout, low bicarbonate), and compare the effects of the different dialysate bicarbonate concentrations on the removal of phosphate and potassium during hemodialysis

Condition or disease Intervention/treatment Phase
Chronic Dialysis Patients Drug: Bicarbonate hemodialysis solution (low concentration) Drug: Bicarbonate hemodialysis solution (high concentration) Phase 4

Detailed Description:
Elevation of blood phosphate levels in chronic dialysis patients is associated with increased mortality due to cardiovascular events, and if sustained leads to hyperactivity of parathyroid glands and renal bone disease. Similarly, increased calcium-phosphate product as a result of elevated levels of phosphate in the blood is an additional risk factor for vascular calcification. Elevated blood potassium levels is another major electrolyte disorder in patients with advanced renal disease which is potentially life threatening. Therefore control of blood phosphate and potassium levels is a fundamental component of treatment for end stage renal disease. Management of hyperelectrolyte levels in renal failure patients requires restriction of phosphate and potassium intake through dietary measures, promotion of excretion via GI tract through medication delivery (i.e. supplementary binders), and removal through dialysis. All these strategies come with limitations however, specifically adherence to dietary restrictions and medication compliance is poor due to lack of immediate repercussions, as well as the complex kinetics involved with removal via dialysis given the dependence on duration and frequency of dialysis whose manipulation is limited by time considerations for the patient and scheduling issues in the dialysis unit.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 12 participants
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effect of Varied Dialysate Bicarbonate Levels on Phosphate and Potassium Removal: A Pilot Study
Study Start Date : March 2010
Actual Primary Completion Date : July 2014
Actual Study Completion Date : December 2014

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Dialysis Potassium

Arm Intervention/treatment
Experimental: Hemodialysis patients
Each patient will be evaluated during a total of 3.5 weeks correlating to routine dialysis treatment appointments. Each participant will start with low bicarbonate, followed by the washout phase (standard bicarbonate), then high bicarbonate, finishing with the follow up period. Dialysis prescription is standardized for each patient throughout the entire 3.5 week study period.
Drug: Bicarbonate hemodialysis solution (low concentration)
One-week experimental session (3 dialysis treatments) with low dialysate bicarbonate (28 mmol/L)

Drug: Bicarbonate hemodialysis solution (high concentration)
One-week experimental session with high dialysate bicarbonate (38 mmol/L)




Primary Outcome Measures :
  1. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 1 (Day 1) - Pre and Post dialysis (0hrs and 4hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)


  2. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 2 (Day 2) - Pre and Post dialysis (0hrs and 4hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)


  3. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 3 (Day 3) - Pre and Post dialysis (0hrs, 4hours, 5hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)


  4. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 7 (Day 15) - Pre and Post dialysis (0hrs, 4hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)


  5. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 8 (Day 16) - Pre and Post dialysis (0hrs, 4hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)


  6. Phosphate/Potassium Removal [ Time Frame: Dialysis Treatment 9 (Day 17) - Pre and Post dialysis (0hrs, 4hours, 5hours) ]

    The amount of phosphate/potassium removed with each dialysis as measured from dialysate aliquots and total calculated volume of dialysate. The following formula will be used to calculate Phosphate (PO4) and Potassium (K) mass removal (mmol/treatment):

    Calculation based on the concentration of K/PO4 (mmol/L) in dialysate x (calculated volume of dialysate + calculated volume of ultrafiltrate)



Secondary Outcome Measures :
  1. Plasma Phosphate Levels [ Time Frame: Baseline and Post Dialysis (4hours) ]
    Measurement of the biochemical (serum) parameters of Phosphate for each dialysis treatment

  2. Plasma Potassium Levels [ Time Frame: Pre and Post Dialysis ]
    Measurement of the biochemical (serum) parameters of Potassium for each dialysis treatment

  3. Total Plasma CO2 (bicarbonate) [ Time Frame: Pre and Post Dialysis (0 and 4hours) ]
    Measurement of the biochemical (serum) parameters of CO2 (bicarbonate) for each dialysis treatment

  4. Corrected Calcium Measurement [ Time Frame: Pre and Post Dialysis (0 and 4hours) ]
    Biochemical measurement of the blood for corrected caclium (calcium and albumin) for each dialysis treatment

  5. Dialysis Adequacy (Kt/ V) [ Time Frame: Pre and Post Dialysis (0 and 4hours) ]
    Measurement of Blood urea will be performed for each dialysis treatment.

  6. Dialysis Adequacy (Urea Reduction Ratio -URR) [ Time Frame: Pre and Post Dialysis (0 and 4hours) ]
    Measurement of Blood urea will be performed for each dialysis treatment.



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Ages Eligible for Study:   up to 18 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patients 0-18 years old
  • Patients receiving maintenance hemodialysis* for a total of 9-15 hours per week
  • Pre-dialysis serum potassium value between 4.0 and 6.5 mmol/L on the first day of the treatment protocol
  • Pre-dialysis serum phosphate value greater than low normal for age on the first day of the treatment protocol
  • Pre-dialysis serum bicarbonate (total CO2) value between 18 and 30 mmol/L on the first day of the treatment protocol
  • Pre-dialysis corrected calcium value between 1.80-2.85 mmol/L on the first day of the treatment protocol

Exclusion Criteria:

  • Hemodynamically unstable patients (requiring inotropes or midodrine for support).
  • Pre-dialysis potassium value < 4.0 or > 6.5 mmol/L on the first day of the treatment protocol
  • Pre-dialysis serum phosphate value less than low normal for age on the first day of the treatment protocol (i.e. hypophosphatemia)
  • Pre-dialysis serum bicarbonate (total CO2) value <18 or > 30 mmol/L on the first day of the treatment protocol
  • Pre-dialysis corrected calcium <1.8 and >2.85 mmol/L on the first day of the treatment protocol
  • Patients mechanically ventilated
  • Drugs that could modify internal phosphate and potassium balance such as insulin, bicarbonate injection, hypertonic dextrose solution or mannitol infusion during HD

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01930370


Locations
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Canada, Ontario
The Hospital for Sick Children
Toronto, Ontario, Canada, M5G 1X8
Sponsors and Collaborators
The Hospital for Sick Children
Investigators
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Principal Investigator: Denis Geary, MD The Hospital for Sick Children

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Responsible Party: Elizabeth Harvey, Project Investigator, The Hospital for Sick Children
ClinicalTrials.gov Identifier: NCT01930370    
Other Study ID Numbers: 1000014657
First Posted: August 28, 2013    Key Record Dates
Last Update Posted: May 28, 2015
Last Verified: May 2015
Keywords provided by Elizabeth Harvey, The Hospital for Sick Children:
pediatrics
phosphate and postassium revmoval
dialysate bicarbonate modeling
Additional relevant MeSH terms:
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Dialysis Solutions
Hemodialysis Solutions
Pharmaceutical Solutions