Validating the use of bioimpedance spectroscopy for assessment of fluid status in children.

Background: Bioimpedance spectroscopy (BIS) with a whole-body model to distinguish excess fluid from major body tissue hydration can provide objective assessment of fluid status. BIS is integrated into the Body Composition Monitor (BCM) and is validated in adults, but not children. This study aimed to (1) assess agreement between BCM-measured total body water (TBW) and a gold standard technique in healthy children, (2) compare TBW_BCM with TBW from Urea Kinetic Modelling (UKM) in haemodialysis children and (3) investigate systematic deviation from zero in measured excess fluid in healthy children across paediatric age range.

Use of the Body Composition Monitor for Fluid Status Measurements in Subjects with High Body Mass Index.

Background: Fluid management is a central aspect of haemodialysis (HD). Body composition monitor (BCM)-measured overhydration (OH) can improve fluid management strategies, but there remains uncertainty about its use in subjects with high body mass index (BMI). This study explored whether the observed tendency for HD patients with high BMI to complete dialysis fluid depleted according to BCM is associated with an artefact in the BCM models, or with systematic differences in the prescription and delivery of treatment.

Risk identification in haemodialysis patients by appropriate body composition assessment.

Introduction: Circumstances such as gender, age, diabetes mellitus (DM) and renal failure impact on the body composition of patients. However, we use nutritional parameters such as lean and fat tissue with reference values from healthy subjects to assess the nutritional status of haemodialysis (HD) patients.

Aims: To analyse body composition by bioimpedance spectroscopy (BIS) of 6395 HD patients in order to obtain reference values of lean tissue index (LTI) and fat tissue index (FTI) from HD patients; and to confirm its validity by showing that those patients with LTI below the 10th percentile calculated for their group have greatest risk of death.

Optimal fluid control can normalize cardiovascular risk markers and limit left ventricular hypertrophy in thrice weekly dialysis patients.

Increased hemodialysis frequency can make fluid overload easier to treat, although most patients are still treated thrice weekly. Chronic fluid overload is associated with left ventricular hypertrophy and elevated serum cardiac biomarkers, recognized as mortality risk factors. Serum cardiac troponin T (cTnT), N-terminal prohormone brain natriuretic peptide (NT-proBNP), left ventricular mass index by cardiac magnetic imaging, and ambulatory blood pressure was measured in 30 thrice weekly hemodiafiltration patients.

Importance of normohydration for the long-term survival of haemodialysis patients.

Background: Fluid overload and hypertension are among the most important risk factors for haemodialysis (HD) patients. The aim of this study was to analyse the impact of fluid overload for the survival of HD patients by using a selected reference population from Tassin.

Methods: A positively selected HD population (n = 50) from Tassin (Lyon-France) was used as a reference for fluid status and all-cause mortality.

Guided optimization of fluid status in haemodialysis patients.

Background: Achieving normohydration remains a non-trivial issue in haemodialysis therapy. Guiding the haemodialysis patient on the path between fluid overload and dehydration should be the clinical target, although it can be difficult to achieve this target in practice. Objective and clinically applicable methods for the determination of the normohydration status on an individual basis are needed to help in the identification of an appropriate target weight.

Importance of whole-body bioimpedance spectroscopy for the management of fluid balance.

Introduction: Achieving normohydration remains a non-trivial issue in haemodialysis therapy. Preventing the deleterious effects of fluid overload and dehydration is difficult to achieve. Objective and clinically applicable methods for the determination of a target representing normohydration are needed.

The mortality risk of overhydration in haemodialysis patients.

Background: While cardiovascular events remain the primary form of mortality in haemodialysis (HD) patients, few centres are aware of the impact of the hydration status (HS). The aim of this study was to investigate how the magnitude of the prevailing overhydration influences long-term survival.

Methods: We measured the hydration status in 269 prevalent HD patients (28% diabetics, dialysis vintage = 41.

A comparison of methods for determining urea distribution volume for routine use in on-line monitoring of haemodialysis adequacy.

Background: The availability of haemodialysis machines equipped with on-line clearance monitoring (OCM) allows frequent assessment of dialysis efficiency and adequacy without the need for blood samples. Accurate estimation of the urea distribution volume 'V' is required for Kt/V calculated from OCM to be consistent with conventional blood sample-based methods.

Methods: Ten stable HD patients were monitored monthly for 6 months.

Towards improved cardiovascular management: the necessity of combining blood pressure and fluid overload.

Background: Hypertension and fluid overload (FO) are well-recognized problems in the chronic kidney disease (CKD) population. While the prevalence of hypertension is well documented, little is known about the severity of FO in this population.

Methods: A new bioimpedance spectroscopy device (BCM-Body Composition Monitor) was selected that allows quantitative determination of the deviation in hydration status from normal ranges (DeltaHS).

A whole-body model to distinguish excess fluid from the hydration of major body tissues.

Background: Excess fluid (ExF) accumulates in the body in many conditions. Currently, there is no consensus regarding methods that adequately distinguish ExF from fat-free mass.

Objective: The aim was to develop a model to determine fixed hydration constants of primary body tissues enabling ExF to be calculated from whole-body measurements of weight, intracellular water (ICWWB), and extracellular water (ECWWB).

Body fluid volume determination via body composition spectroscopy in health and disease.

The assessment of extra-, intracellular and total body water (ECW, ICW, TBW) is important in many clinical situations. Bioimpedance spectroscopy (BIS) has advantages over dilution methods in terms of usability and reproducibility, but a careful analysis reveals systematic deviations in extremes of body composition and morbid states. Recent publications stress the need to set up and validate BIS equations in a wide variety of healthy subjects and patients with fluid imbalance.

The relationship between systemic and whole-body hematocrit is not constant during ultrafiltration on hemodialysis.

The measurement of relative blood volume (RBV) changes during ultrafiltration assume a constant mass and distribution of circulating blood components such as hematocrit. The authors examine the validity of this assumption in 10 subjects undergoing repeated direct measurements of systemic hematocrit and plasma volume (PV(icg)) using indocyanine green dilution at four stages of dialysis with intermittent ultrafiltration. Ultrasonic RBV changes were monitored.

Serial determinations of absolute plasma volume with indocyanine green during hemodialysis.

Hemodynamic stability during hemodialysis depends largely on plasma volume (PV) preservation during ultrafiltration (UF). Current estimates of blood volume (BV) are indirect or involve the use of radioactive tracers, which does not allow repeated measurements during hemodialysis. Indocyanine green was used to measure PV during hemodialysis.

Linear decay of relative blood volume during ultrafiltration predicts hemodynamic instability.

Background: Relative blood volume (RBV) changes during hemodialysis (HD) are poorly understood. We wish to define characteristics of RBV profiles at different hydration states predictive of hemodynamic instability.

Methods: Thirty patients underwent online RBV monitoring during an HD session with intermittent ultrafiltration (UF) pulses administered until the onset of hypotension.

A new technique for establishing dry weight in hemodialysis patients via whole body bioimpedance.

Background: Quantitative techniques are necessary to achieve dry weight (DW) in patients with kidney failure. Bioimpedance spectroscopy (BIS) is a non-invasive method that determines the volume of body fluid compartments. The current work evaluates the use of BIS data in hemodialysis patients for the prediction of DW.

Phosphate kinetics during hemodialysis: Evidence for biphasic regulation.

Background: Hyperphosphatemia in the hemodialysis population is ubiquitous, but phosphate kinetics during hemodialysis is poorly understood.

Methods: Twenty-nine hemodialysis patients each received one long and one short dialysis, equivalent in terms of urea clearance. Phosphate concentrations were measured during each treatment and for one hour thereafter.