Bioimpedance Spectroscopy (BIS): Fluid Changes in Hemodialysis Patients

August 31, 2026 updated by: Per Ivarsen

Bioimpedance Spectroscopy (BIS): Analysis of Changes in Fluid Status in Hemodialysis Patients

In connection with dialysis treatment, fluid and salt balance changes. Some kidney disease patients experience fluid accumulation in the body and need to have excess fluid removed via the dialysis machine. Others have too little fluid in their bodies and experience general symptoms. The amount of fluid that needs to be removed is an individual assessment and can be difficult to determine. Today, fluid removal is determined based on signs such as water in the lungs, swollen legs, and blood pressure. By using a so-called bioimpedance spectroscopy (BIS) device, it os possible measure how much fluid is in the body. However, the calculations that BIS devices use are developed for healthy individuals and do not work optimally during dialysis. Therefore, the investigators will use the actual measurements and compare them with fluid extraction and weight changes to examine their relationship. Hemodialysis patients with ultrafiltration on 3 consecutive dialysis days in order to investigate whether there is a difference in measurements after the long dialysis break and whether the measurements are the same when you are being drawn to your dry weight are included. Other patients without fluid removed during dialysis will be investigated once. I the study the absolute blood volume is also measured, that is, how much fluid is in the bloodstream. This is also an expression of the body's total fluid volume. By combining the various measurements, the study will gain increased knowledge about your hydration status. If the measurement methods have sufficient precision, the use of BIS and measurement of total blood volume may contribute to a more accurate determination of your dry weight.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

To investigate whether raw impedance data from BIS measurements can be used as a tool to estimate changes in fluid status in HD patients. Accuracy is low when using prediction equations that are integrated into the individual BIS device. This challenges the application in clinical practice. Furthermore, the prediction equation is not available for most devices. Small studies suggest greater accuracy when using raw data, which could make BIS measurements clinically applicable. Detailed purpose. To examine whether raw impedance data from BIS measurements can be used as a tool to estimate changes in fluid status in HD patients.

  1. Ensure consistency in measurements of raw impedance data (Phase angle, RE, RI, R∞, and Cm) between different BIS devices (here: Fresenius BCM®, SFB7®, and SOZO® from ImpediMed).
  2. Compare intradialytic ∆RE, ∆R∞, and ∆Cm against changes in absolute blood volume, BP, weight, and fluid removal in HD patients with fluid removal.
  3. Is the phase angle consistent over the 3 dialysis days in a week for center dialysis patients with fluid retention?
  4. Compare intradialytic ∆RE, ∆R∞, and ∆Cm against changes in absolute blood volume, blood pressure, and weight in hemodialysis patients without fluid retention.
  5. Compare intradialytic ∆blood pressure, ∆weight, ∆ABV, fluid retention, and BIS measured changes (∆RE, ∆R∞, ∆Cm) for patients undergoing home hemodialysis with patients undergoing center hemodialysis.

Study Type

Interventional

Enrollment (Estimated)

42

Phase

  • 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 Contact

Study Locations

  • Denmark
    • Central Denmark
      • Aarhus, Central Denmark, Denmark, 8200

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Hemodialysis for more than 3 month Hemodynamic stabile during a dialysis session

-

Exclusion Criteria:

  1. Amputated limbs.
  2. Pregnant.
  3. Extremity palsy and paralysis.
  4. Implanted electronic device (e.g., pacemaker or ICD).
  5. Regular use of dialysate sodium proliferation.
  6. Hip, knee and shoulder prosthesis.
  7. Dialysis fistula in both arms.
  8. Inability to give informed consent.
  9. History of discontinuation of dialysis treatment prematurely.

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: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Hemodialysis patient
Measurement wil be donne before and after a hemodialysis. Bioimpendance spectroscopy is measured with 3 different bioimpedance apperatur. Absolute blood volumen is measured 5-10 minutes after starting and before stopping the dialysis session. For center hemodialysis patients with ultrafiltration measurement til be performed on 3 consecutive days and for patient center hemodialysis patient meaurement wil be performed once with also apply for Home hemodialysis patients.
Device: Bioimpedance analysis
Comparing the perfomance of original data from 3 different bioimpedance apparatur and test there precision and accurary compared to ultrafiltration. And whether the performance of measuring absolut blood volume is better

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in BIS measured resistance and fluid removed
Time Frame: From enrollment to the end of the dialysis session

To investigate whether raw impedance data from BIS measurements can be used as a tool to estimate changes in fluid status in HD patients before and after a hemodialysis session of 4 hours duration. Weight loss during a hemodialysis session is equivalent to fluid removed. The meausement are don for up to oen week

  1. To determine consistency in measurements of raw impedance data (Ω) between different BIS devices (here: Fresenius BCM ®, SFB7 ® and SOZO ® from Imped-iMed).
  2. Change in raw impedance data (Ω) during a hemodialysis session of 4 hours
  3. Degree of ultrafiltrating (ml) a hemodialysis session of 4 hours
  4. Change in absolute blood volume (ml) during a hemodialysis session of 4 hours

4) In a subset of patients test if the length of the of pause (days) between hemodialysis session influence the raw impedance measurements.
From enrollment to the end of the dialysis session

Collaborators and Investigators

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

Sponsor

Per Ivarsen

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 (Actual)

May 11, 2025

Primary Completion (Estimated)

October 16, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

August 3, 2026

First Submitted That Met QC Criteria

August 31, 2026

First Posted (Actual)

September 3, 2026

Study Record Updates

Last Update Posted (Actual)

September 3, 2026

Last Update Submitted That Met QC Criteria

August 31, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VMK2500694

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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