Validation of Body Composition Monitor (BCM) in pediatric dialysis patients

Cardiovascular disease (CVD) is the main cause of death in patients with
pediatric onset of end-stage renal disease. Chronic overhydration in dialyzed
children is an important determinant of cardiac dysfunction and hypertension.
In current practice, fluid status is clinically assessed, which is known to be
inaccurate, especially in children. Recently, non-invasive assessment of extra-
and intracellular water by means of Body Composition Monitor (BCM) has been
advocated. BCM assessment of fluid compartments relies on the mathematical
modeling of body compartments and has been validated in adults. As the body
composition in children differs from that in adults with respect to total and
extracellular water, we want to verify if the BCM algorithms are applicable in
children.
The gold standards to assess the main body volumes, total body water (TBW) and
extracellular water (ECW), are deuterium and sodium bromide dilution,
respectively. They are safe and accurate techniques, but unpractical in the
clinical setting. BCM is a non-invasive and bedside technique, that can
determine TBW and ECW in less than two minutes. It has been validated in
healthy subjects and dialyzed adults, but not in pediatric dialysis patients.

Primary Objective:
Validation of the Fresenius BCM in pediatric dialysis patients for the
assessment of TBW and ECW using dilution techniques as the reference methods.

Secondary Objective:
Validation of saliva sampling for bromide concentration measurement in the
bromide dilution technique for ECW estimation, using plasma as the reference
method.

Study participants will undergo TBW and ECW measurements by standardized
dilution methods and BCM:
* Deuterium and sodium bromide dilutions:
After an overnight fast subjects are required to drink 0,06 ml/kg of a solution
containing deuterium and, after 3 hours, 10 ml of a sodium bromide solution.
Both deuterium and sodium bromide are innocuous fluids. Samples of saliva are
collected prior to ingestion of the deuterium solution and after 2,3 and 4
hours. Two blood samples of 2 ml each are required: one prior to ingestion of
sodium bromide and one 3 hours later.
BCM measurements:
For BCM measurement, the subject is required to remain quiet and recumbent for
the duration of the test. Electrodes are applied and body composition
measurement is performed in less than 2 min. It is a painless procedure. BCM
measurements will be obtained between sodium bromide intake and the last blood
sample.
* Additional measurements:
Two further samples of saliva are collected just before the final blood sample
to validate the assessment of ECW by bromide concentration in saliva.

The burden and risks are linked to the fast, blood sampling, prolongation of
duration of hospital visit. The use of bromide and deuterium is safe and
adverse effects are not to be expected.
This study will provide important data on the applicability BCM in dialyzed
children to monitor fluid balance in a non-invasive and easy way, which is a
direct benefit to the quality of care of children on dialysis.