Evaluation of Volume and Electrolyte Balance in Hyponatremia Treatment - a Prospective Observational Trial

Study Overview
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Brief Summary
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To assess quantitatively the evolution over time of electrolyte-free water clearance and electrolyte mass balance in patients with non-hypervolemic hypotonic hyponatremia

Detailed Description
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Achieving recommended treatment targets in management of hyponatremia is challenging: plasma sodium must be increased effectively but, at the same time, overcorrection has to be prevented. Yet, predictors of change of sodium over time have not been delineated properly. It was found, that evidence hinting to the fact that sodium baseline itself is crucial with respect to sodium evolution. The goal of this study is to gather prospective data in order to precisely delineate the role of initial sodium levels by correlating those to plasma sodium evolution and electrolyte free water evolution. It is aimed to decipher patterns of sodium evolution with respect to anthropometric data, such as body composition analyses and blood pressure and markers of innate regulation mechanisms of body volume like aldosterone and renin. In addition, apart from these clinical aspects, a better appreciation of the physiological responses to hyponatremia treatment in terms of water and electrolyte balances is undoubtedly necessary to improve understanding of the body's mechanisms involved in osmotic homeostasis and cell volume control. Since studies to date also lack consideration of the intracellular department, the aim is to close that gap.

Official Title
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Evaluation of Volume and Electrolyte Balance in Hyponatremia Treatment - a Prospective Observational Trial (EvenT)

Conditions
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Non-hypervolemic Hyponatremia

Intervention / Treatment
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* Other: Patients


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients ≥ 18 years Hypotonic hyponatremia glucose-corrected plasma sodium <130 mmol/l serum osmolality <280 mosmol/kg or lack of signs of non-hypotonic hyponatremia Exclusion Criteria: Signs of extracellular volume expansion Patients with liver cirrhosis and severe liver damage AST/ALT>3xULN, AP>6xULN, Bilirubin ≥ 3mg/dl Patients with heart failure Patients on dialysis and/or patients with oliguric renal impairment and plasma creatinine ≥ 3mg/dl Patients after organ transplantation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients<br>Patients with non-hypervolemic hypotonic hyponatremia | Other: Patients<br>* Patients will get study-specific measurements within first 5 days of standard of care treatment of hyponatremia or until discharge<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Plasma Sodium | Measurement of plasma sodium in blood samples | baseline, every day up to 30 days | 
| Changes in plasma osmolality | Measurement of plasma osmolality for determination of electrolyte-free water clearance before, during and after hyponatremia treatment | baseline, every day up to 30 days | 
| Changes in urine osmolality | Determination of electrolyte-free water clearance before, during and after hyponatremia treatment by measurement of urine osmolality | baseline, every day up to 30 days | 
| Changes in urine volume | Determination of electrolyte-free water clearance before, during and after hyponatremia treatment by measurement of urine volume | baseline, every day up to 30 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in body weight | Measurement of body weight before, during and after hyponatremia treatment by bioimpedance measurement | baseline, every day up to 30 days | 
| Changes in total body water | Measurement of body water before, during and after hyponatremia treatment by bioimpedance measurement | baseline, every day up to 30 days | 
| Changes in intracellular volume | Measurement of intracellular volume before, during and after hyponatremia treatment by bioimpedance measurement | baseline, every day up to 30 days | 
| Changes in extracellular volume | Measurement of extracellular volume before, during and after hyponatremia treatment by bioimpedance measurement | baseline, every day up to 30 days | 
| Changes in blood pressure | Measurement of blood pressure before, during and after hyponatremia treatment | baseline, every day up to 30 days | 
| Changes in cell size | Determination of blood cell size via measurement of mean corpuscular volume | baseline, every day up to 30 days | 
| Changes in intracellular electrolyte levels | Measurement of whole blood samples via ICP-mass spectrometry | baseline, every day up to 30 days | 
| Changes in copeptin levels | Measurement of copeptin in blood samples | baseline, every day up to 30 days | 
| Changes in renin levels | Measurement of renin in blood samples | baseline, every day up to 30 days | 
| Changes in aldosterone levels | Measurement of aldosterone in blood samples | baseline, every day up to 30 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Electrolyte-free water clearance, hyponatremia