Hemodialysis Blood Flow and Urea Clearance

December 7, 2015 updated by: University of British Columbia

Examining the Effect of Blood Flow Rate on Hemodialysis Urea Clearance

The study purpose is to determine whether two different hemodialysis blood flow rates each meet national dialysis standards for urea clearance. Urea is used as the primary marker of dialysis adequacy. It is an experimental study with a crossover design of minimum 38 participants. Participants will be selected from the accessible pool of end-stage renal disease clients at the Vancouver Community Dialysis Unit. The participants will dialyse at each pre-determined blood flow rate (320 mL/min and 380 mL/min) for two weeks each. Two forms of urea clearance data will be collected: one value that is routinely calculated by the dialysis machine and recorded on client treatment logs, and another that is calculated in a lab from blood samples.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Design This quasi-experimental study involves the independent variable of blood flow rate (Qb), measured in mL/min, and the dependent variable of dialysis clearance, measured by Kt/V and URR (urea reduction ratio). Control and randomization will be manifested in a crossover design, which provides the benefit of separating treatment effects from period effects (Wellek & Blettner, 2012). Participants will be randomly assigned - by way of selecting names from an envelope - to one of two groups: A, which dialyses first at 320 mL/min; or B, at 380 mL/min. Each study period will consist of two weeks (6 sessions, 24 hours of dialysis) at each Qb. Because urea clearance is immediate, six treatments at each Qb will reflect accurate data on Kt/V and URR (Dr. John Duncan, 2014, personal communication). Although carryover effects are not of concern to this study as participants routinely dialyse three times per week, wherein urea levels naturally rise between routine treatments, a washout phase of one week between study periods will occur, as is recommended for an effective crossover design (Wellek & Blettner, 2012).

Sample

The target and sample population are end-stage renal disease patients dialysing with an arteriovenous fistula (AVF) at the Vancouver Community Dialysis Unit. Power analysis was conducted by the Centre for Health Evaluation and Outcome Sciences (CHEOS). To ensure a Kt/V of 1.3 and URR of 70% can be estimated with a confidence interval of 95%, a minimum sample size of 34 participants is required. An additional 10% is necessary to account for attrition. Because randomization will occur with study period assignment, purposive sampling will be used to select participants from the accessible pool (estimated at 60 patients), until 38 participants are identified. The inclusion criteria are:

Dialysing for greater than six months to ensure access patency, viability, and stability; Undergoing thrice weekly, four-hour dialysis sessions for uniform dialysis duration; Dialysing with an AVF, either brachio-cephalic or radio-cephalic; no central venous catheters, arteriovenous grafts, or femoral AVFs due to differences in access flows and vessel quality; BLOOD FLOW RATE 5 Dialysing with 15g needles as organization policy restricts greater flow rates with smaller needle gauge; Dialysing with a dialysate flow (Qd) of 500 mL/min to reduce the possibility of clearance being attributable to differences in Qd; Maintaining transonic vascular access flows of >600 mL/min for the past 6 months, per KDOQI (NKF, 2006) minimum flow guidelines, to ensure access patency; Not part of any other research study that would interfere with dialysis treatment.

Data Collection Hourly documentation of Qb is routine protocol in the HD (hemodialysis) unit, along with Kt/V at each treatment termination. URR is routinely drawn every 6 weeks, however during this study it will be drawn weekly, on each third treatment. Standard URR blood draw protocol will be followed: a pre- and post- dialysis blood specimen will be collected and sent, along with the corresponding requisition, for analysis and calculation. A research account will be opened with LifeLabs (local laboratory service) and all research requisitions and blood will be coded and billed to the research study. Per unit protocol, blood draws will be written in the unit diary for nurse awareness, and blood collection tubes and requisition placed in participants' charts the night prior to treatment. Once weekly, the researchers will photocopy the participants' treatment run logs, along with the urea lab report, and data will be inputted into a CHEOS-approved excel spreadsheet. Along with Qb and Kt/V, collected data will include participants' blood pressure, dialysate flow rate, dialysis duration, needle gauge and cannulation, and occurrence of any intradialytic complications.

Data Analysis Data analysis will be conducted by CHEOS.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
24

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada, V5Z 1M9
        • University of British Columbia, Division of Nephrology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

Participants will be selected from the Vancouver Community Dialysis Unit.

The inclusion criteria for participant selection will be:

  1. Dialysing for greater than six months to ensure access patency, viability, and stability;
  2. Undergoing thrice weekly, four-hour dialysis sessions for uniform dialysis duration;
  3. Dialysing with an arteriovenous fistula, either brachio-cephalic or radio-cephalic, to control variances in blood flow rates related to vascular access;
  4. Dialysing with 15g needles as organization policy restricts greater flow rates with smaller needle gauge;
  5. Dialysing with a dialysate flow (Qd) of 500 mL/min to reduce the possibility of clearance being attributable to differences in Qd;
  6. Maintaining transonic vascular access flows of >600 mL/min for the past 6 months, per Kidney Dialysis Outcomes Quality Initiative (KDOQI) (NKF, 2006) minimum flow guidelines, to ensure access patency.

Exclusion Criteria:

Patients who speak a language other than English, Cantonese, Mandarin, or Punjabi will be excluded due to funding constraints for providing translated informed consent documents. Informed consent documents will only be available in the languages listed above, which are the most common languages spoken/read at the dialysis unit.

Patients who dialyse with a central venous catheter, arteriovenous graft, or femoral arteriovenous fistula will not be invited to participate due to potential confounding from known differences in access flows and vessel quality that may impact clearance values.

Patients who are involved in any other research study that would interfere with their dialysis treatment would be excluded from the study.

Patients who are hemodynamically unstable (e.g.: frequent 'crashing' due to severe hypotension) will be excluded due to the instability this would pose on achieving their prescribed dialysis time (e.g.: if they crash, they may be taken off dialysis early) and resulting data.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Targeted blood flow rate 320 ml/min
Hemodialysis blood flow will be targeted at 320 ml/min during hemodialysis for two weeks
Procedure: Hemodialysis blood flow
The impact of blood flow rates of 320 ml/m and 380 ml/m will be compared to determine any impact on hemodialysis urea clearance
Experimental: Targeted blood flow rate 380 ml/min
Hemodialysis blood flow will be targeted at 380 ml/min during hemodialysis for two weeks
Procedure: Hemodialysis blood flow
The impact of blood flow rates of 320 ml/m and 380 ml/m will be compared to determine any impact on hemodialysis urea clearance

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Urea clearance
Time Frame: Two weeks of dialysis at each blood flow rate
Two weeks of dialysis at each blood flow rate

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of British Columbia

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: John A Duncan, MSc MD FRCPC, University of British Columbia

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2015

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2015

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 4, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 24, 2015

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 29, 2015

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 9, 2015

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 7, 2015

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2015

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • H14-01931

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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