HyponatremiaRESERVENCT06408077
Regulation of Extracellular Sodium in End Stage Renal Disease Upon Volume and Electrolyte Challenges
A study testing Water administration and NaCl-Administration in people with Hyponatremia, run by University of Cologne at 1 site in Germany.
Trial summary
Hyponatremia is the most common electrolyte disorder of all and can be observed in more than 30% of all patients in hospitals. Osmotic homeostasis of body fluids is essential for survival of all living creatures. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hyponatremia
- What is being tested?
- Water administration and NaCl-Administration
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteGermany
- Study dates
- 1 Jul 2023to 31 May 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients ≥18 years
- Requirement of renal replacement therapy due to surgical (i.e., nephrectomy) or non-surgical (chronic kidney disease) reason
- Stable hemodialysis treatment for at least 3 months
- Urine output <100ml in 24 hours
- Glucose-corrected plasma sodium between 135 mmol/l and 145 mmol/l
- Plasma potassium between 3.5 mmol/l and 5 mmol/l
- Written informed consent
Who cannot join
- Peritoneal dialysis patients
- Signs of volume expansion or contraction
- Congestive heart failure (NYHA ≥2)
- acute illness (infection, congestive heart failure, liver cirrhosis, etc.) requiring hospital admission
- Uncontrolled arterial hypertension
- Hemoglobin ≤8g/dL
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- Alcohol abuse
- Malnutrition
- Persons, who are in a dependency/employment relationship with the investigators
- Accommodation in an institution by judicial or administrative order
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Sadrija Cukoski, MD contact
Germany1 site, 1 recruiting
- Recruiting
Department II of Internal Medicine,University of Cologne
Cologne, 50937
Volker Burst, MD, +49 221 478 86285, volker.burst@uk-koeln.de
Cornelia Böhme, +49 221 478 97222, cornelia.boehme@uk-koeln.de
About this study
Official title: Regulation of Extracellular Sodium in End Stage Renal Disease Upon Volume and Electrolyte Challenges - a Prospective Trial.
Hyponatremia is the most common electrolyte disorder of all and can be observed in more than 30% of all patients in hospitals. Osmotic homeostasis of body fluids is essential for survival of all living creatures. It is widely accepted that extra- and intracellular osmolalities are in equilibrium at all times and thus, changes in the extracellular osmolality will lead to either shrinkage or swelling of cells which can be detrimental. In severe cases, it can lead to swelling of the brain and death. Even in less dramatic scenarios, symptoms such as epileptic seizures, headaches, depression and dizziness exist, leading to an increased risk of fractures, hospital admissions and a considerable burden for affected patients.
As short-term defense against osmotic stress, each individual cell is capable of actively externalizing or internalizing osmotically active solutes which restores normal or near-normal cell volume at the expense of an altered milieu interior. Obviously, there must be limitations to this strategy if intracellular integrity is meant to be kept stable. It has therefore been postulated that, apart from this cell-immanent mechanism, extracellular and intracellular electrolyte stores could assist in buffering osmotic imbalances.
Read more
The Edelman formula states that extracellular sodium is determined by the total amount of exchangeable body sodium (the major extracellular cation) plus potassium (the major intracellular cation) divided by total body water. Several studies have shown, that it only partially explains the changes in patients outside the osmotic equilibrium.
To better understand these physiological responses might not only promote the researcher's insight into the most basic cellular self-defense systems by measuring and comparing extra- and intracellular electrolyte concentrations with estimated changes in a patient that will be intravenously challenged with either water or sodium chloride 3%.
The evolution over time of extra- and intracellular sodium and other electrolytes will be assessed quantitatively in patients with impaired renal function after water or sodium chloride (NaCl) administration.
- Conditions
- Hyponatremia
- Being tested
- Water administration, NaCl-Administration
- Keywords
- hyponatremia, prospective trial, intracellular measurements, Water-Electrolyte Imbalance
- Medical subject headings
- Hyponatremia, Water-Electrolyte Imbalance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Water administrationOther
Intravenous administration of water (Aqua ad injectabilia) until a decrease of plasma sodium of 5 to 8 mmol/l has been achieved
NaCl-AdministrationOther
Intravenous administration of NaCl 3% until an increase of plasma sodium of 5 to 8 mmol/l has been achieved
| Study group | Role | What they receive |
|---|---|---|
| Water-Group | Experimental | Intravenous administration of water (Aqua ad injectabilia) until a decrease of plasma sodium of 5 to 8 mmol/l has been achieved Receives: Other: Water administration |
| NaCl-Group | Experimental | Intravenous administration of NaCl 3% until an increase of plasma sodium of 5 to 8 mmol/l has been achieved Receives: Other: NaCl-Administration |
What is being measured
The primary outcome is the main question the study is designed to answer.
acute changes of extracellular osmolality
The primary aim is to compare the actual acute change of extracellular sodium with the estimated change of extracellular sodium in response to an intravenous challenge with either water or sodium. Precise evaluation of the validity of the concept of Edelman in acute changes of extracellular osmolality
Measured: 300 minutes after infusion
Secondary outcomes (4)
change of extracellular electrolyte concentrations
extracellular electrolyte concentrations in response to an intravenous challenge with either water or sodium.
Measured: 300 minutes after infusion
change of intracellular electrolyte concentrations
intracellular (red blood cells/white blood cells) electrolyte concentrations in response to an intravenous challenge with either water or sodium.
Measured: 300 minutes after infusion
change of osmolality
change of osmolality in response to an intravenous challenge with either water or sodium
Measured: 300 minutes after infusion
change of cell volume
cell volume (red blood cells) in response to an intravenous challenge with either water or sodium
Measured: 300 minutes after infusion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 May 2024
- Study start1 Jul 2023
- Primary completion31 May 2026 (estimated)
- Study completion31 May 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HyponatremiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Cologne
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Volker Burst, University of Cologne
- Investigators
- Volker Burst, MD, Principal investigator, University Hospital of Cologne
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06408077
- Sponsor's protocol ID
- V1.2_2023-06-06
- Acronym
- RESERVE
- Status last verified
- Sep 2025
- First submitted
- 3 May 2024
- Last updated
- 17 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Regulation of Extracellular Sodium in End Stage Renal Disease Upon Volume and Electrolyte Challenges - a Prospective Trial.
- ClinicalTrials.gov ID
- NCT06408077
- Acronym / sponsor ID
- RESERVE / V1.2_2023-06-06
- Conditions
- Hyponatremia
- Keywords
- hyponatremia, prospective trial, intracellular measurements, Water-Electrolyte Imbalance
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- University of CologneUniversity, hospital or other
- Study start
- 1 Jul 2023 (actual)
- Primary completion
- 31 May 2026 (estimated)
- Study completion
- 31 May 2026 (estimated)
- First posted
- 9 May 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Hyponatremia is the most common electrolyte disorder of all and can be observed in more than 30% of all patients in hospitals. Osmotic homeostasis of body fluids is essential for survival of all living creatures. It is widely accepted that extra- and intracellular osmolalities are in equilibrium at all times and thus, changes in the extracellular osmolality will lead to either shrinkage or swelling of cells which can be detrimental. In severe cases, it can lead to swelling of the brain and death. Even in less dramatic scenarios, symptoms such as epileptic seizures, headaches, depression and dizziness exist, leading to an increased risk of fractures, hospital admissions and a considerable burden for affected patients.
As short-term defense against osmotic stress, each individual cell is capable of actively externalizing or internalizing osmotically active solutes which restores normal or near-normal cell volume at the expense of an altered milieu interior. Obviously, there must be limitations to this strategy if intracellular integrity is meant to be kept stable. It has therefore been postulated that, apart from this cell-immanent mechanism, extracellular and intracellular electrolyte stores could assist in buffering osmotic imbalances.
The Edelman formula states that extracellular sodium is determined by the total amount of exchangeable body sodium (the major extracellular cation) plus potassium (the major intracellular cation) divided by total body water. Several studies have shown, that it only partially explains the changes in patients outside the osmotic equilibrium.
To better understand these physiological responses might not only promote the researcher's insight into the most basic cellular self-defense systems by measuring and comparing extra- and intracellular electrolyte concentrations with estimated changes in a patient that will be intravenously challenged with either water or sodium chloride 3%.
The evolution over time of extra- and intracellular sodium and other electrolytes will be assessed quantitatively in patients with impaired renal function after water or sodium chloride (NaCl) administration.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Water-Group | Experimental | Other: Water administrationIntravenous administration of water (Aqua ad injectabilia) until a decrease of plasma sodium of 5 to 8 mmol/l has been achieved |
| NaCl-Group | Experimental | Other: NaCl-AdministrationIntravenous administration of NaCl 3% until an increase of plasma sodium of 5 to 8 mmol/l has been achieved |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Adult patients ≥18 years
- Requirement of renal replacement therapy due to surgical (i.e., nephrectomy) or non-surgical (chronic kidney disease) reason
- Stable hemodialysis treatment for at least 3 months
- Urine output <100ml in 24 hours
- Glucose-corrected plasma sodium between 135 mmol/l and 145 mmol/l
Key exclusion criteria (10 listed)
- Peritoneal dialysis patients
- Signs of volume expansion or contraction
- Congestive heart failure (NYHA ≥2)
- acute illness (infection, congestive heart failure, liver cirrhosis, etc.) requiring hospital admission
- Uncontrolled arterial hypertension
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Water administrationIntravenous administration of water (Aqua ad injectabilia) until a decrease of plasma sodium of 5 to 8 mmol/l has been achieved | Other | Water-Group |
| NaCl-AdministrationIntravenous administration of NaCl 3% until an increase of plasma sodium of 5 to 8 mmol/l has been achieved | Other | NaCl-Group |
Primary outcome
acute changes of extracellular osmolality
Time frame: 300 minutes after infusion
The primary aim is to compare the actual acute change of extracellular sodium with the estimated change of extracellular sodium in response to an intravenous challenge with either water or sodium. Precise evaluation of the validity of the concept of Edelman in acute changes of extracellular osmolality
4 secondary outcomes
change of extracellular electrolyte concentrations
Time frame: 300 minutes after infusion
change of intracellular electrolyte concentrations
Time frame: 300 minutes after infusion
change of osmolality
Time frame: 300 minutes after infusion
change of cell volume
Time frame: 300 minutes after infusion
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sadrija Cukoski, MD contact
Volker Burst, MD principal investigator
University Hospital of Cologne
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Water administration and NaCl-Administration in people with Hyponatremia, run by University of Cologne at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Volker Burst, MD (+49 221 478 86285, volker.burst@uk-koeln.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
acute changes of extracellular osmolality (time frame: 300 minutes after infusion). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2025.