Evaluation of multifrequency bioimpedance spectroscopy for measurement of the extracellular water space in critically ill patients

Plank, Lindsay D.; Monk, David; Woollard, Gerald A.; Hill, Graham L.

doi:10.1016/s0969-8043(97)00060-2

Cited by 27 publications

(43 citation statements)

References 4 publications

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“…It relies on an electrical model based on resistances measured at zero and infinite frequencies in tissues [19], [20]. The method is useful to assess ECW in healthy subjects and in critically ill patients [51]. Similarly to what we observed with BIA, the ECW estimates by BIS and Br − were highly comparable, showing that this method can also be employed to determine ECW in GHD adults.…”

Section: Discussionsupporting

confidence: 64%

Extracellular Water and Blood Pressure in Adults with Growth Hormone (GH) Deficiency: A Genotype-Phenotype Association Study

et al. 2014

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ObjectivesGrowth hormone deficiency (GHD) in adults is associated with decreased extracellular water volume (ECW). In response to GH replacement therapy (GHRT), ECW increases and blood pressure (BP) reduces or remains unchanged. Our primary aim was to study the association between polymorphisms in genes related to renal tubular function with ECW and BP before and 1 year after GHRT. The ECW measures using bioimpedance analysis (BIA) and bioimpedance spectroscopy (BIS) were validated against a reference method, the sodium bromide dilution method (Br−).Design and MethodsUsing a candidate gene approach, fifteen single-nucleotide polymorphisms (SNPs) in nine genes with known impact on renal tubular function (AGT, SCNN1A, SCNN1G, SLC12A1, SLC12A3, KCNJ1, STK39, WNK1 and CASR) were genotyped and analyzed for associations with ECW and BP at baseline and with their changes after 1 year of GHRT in 311 adult GHD patients. ECW was measured with the Br−, BIA, and BIS.ResultsBoth BIA and BIS measurements demonstrated similar ECW results as the reference method. At baseline, after adjustment for sex and BMI, SNP rs2291340 in the SLC12A1 gene was associated with ECW volume in GHD patients (p = 0.039). None of the SNPs influenced the ECW response to GHRT. One SNP in the SLC12A3 gene (rs11643718; p = 0.024) and three SNPs in the SCNN1G gene [rs5723 (p = 0.02), rs5729 (p = 0.016) and rs13331086 (p = 0.035)] were associated with the inter-individual differences in BP levels at baseline. A polymorphism in the calcium-sensing receptor (CASR) gene (rs1965357) was associated with changes in systolic BP after GHRT (p = 0.036). None of these associations remained statistically significant when corrected for multiple testing.ConclusionThe BIA and BIS are as accurate as Br− to measure ECW in GHD adults before and during GHRT. Our study provides the first evidence that individual polymorphisms may have clinically relevant effects on ECW and BP in GHD adults.

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Section: Discussionsupporting

confidence: 64%

Extracellular Water and Blood Pressure in Adults with Growth Hormone (GH) Deficiency: A Genotype-Phenotype Association Study

et al. 2014

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“…Furthermore, as¯uid shifts are often present in patients, TBW is not a good measure for nutritional status, because it includes intracellular water and extracel-lular water, which may be expanded in depletion and disease. 4,5 Intracellular water (ICW) or body cell mass (BCM) would there-fore be more appropriate for nutritional assessment, as this compartment represents the active living part of the body.…”

Section: Introductionmentioning

confidence: 99%

Validation of bio-impedance spectroscopy: Effects of degree of obesity and ways of calculating volumes from measured resistance values

Cox-Reijven¹,

Soeters

2000

Int J Obes

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BACKGROUND: Bioelectrical-impedance spectroscopy (BIS) is a very attractive method for body composition measurements in a clinical setting. However, validation studies often yield different results. This can partly be explained by the different approaches used to transform measured resistance values into body compartments. OBJECTIVE: The aim of this study was to compare the linear regression (LR) method with the Hanai Mixture theory (HM). Secondly, the effect of degree of overweight on the accuracy of BIS was analysed. DESIGN: In 90 people (10 M, 80 F; body mass index (BMI) 23 ± 62 kgam 2 ) total body water (TBW) and extracellular water (ECW) were measured by deuterium and NaBr dilution methods, respectively, and by BIS. Resistance values of ECW (R ECW ) and TBW (R TBW ) were used for volume calculations. Data of half the group were used for LR based on L 2 aR (L length, R resistance) to predict TBW and ECW and to calculate the constants used in the HM (k ECW ), k p ). Prediction equations and constants were cross-validated in Group 2. RESULTS: Bland and Altman analysis showed that the LR method underestimated TBW by 1.1 l (P`0.005) and ECW by 1.1 l (P`0.005). The HM approach underestimated ECW by 0.8 l (P`0.005). The correlations with the dilution methods and the SEEs for TBW and ECW were comparable for the two approaches. The prediction error of BIS for TBW and ECW correlated with BMI. The constant k ECW , and the speci®c resistivities of the ECW and intracellular water (ICW) p ECW and p ICW were also correlated with BMI. CONCLUSIONS: The mixture approach is slightly more accurate than linear regression, but not sensitive enough for clinical use. The constants used in the HM model are not constants in a population with a wide variation in degree of overweight. The physical causes of the correlation between BMI and constants used in the model should be studied further in order to optimize the mixture model.

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“…22 In critically ill patients, BIS was shown to accurately measure ECW changes. 34,35 In contrast, BIS was shown to overestimate both TBW and ECW changes in obese individuals undergoing weight loss. 42 This review of the BIS literature has focused on validation studies with particular relevance to the clinician.…”

Section: Discussionmentioning

confidence: 93%

Bioimpedance Spectroscopy for Clinical Assessment of Fluid Distribution and Body Cell Mass

et al. 2007

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Body composition assessment has been used to evaluate clinical interventions in research trials, and has the potential to improve patient care in the clinical setting. Body cell mass (BCM) is an important indicator of nutrition status; however, its measurement in the clinic has been limited. BCM can be estimated by the measurement of intracellular water (ICW). The assessment of extracellular water (ECW) is also important because many clinical populations undergo alterations in fluid distribution, particularly individuals with wasting, those receiving dialysis, and obese individuals. Bioimpedance spectroscopy (BIS) is a unique bioimpedance approach that differs in underlying basis from the more readily recognized single-frequency bioelectrical impedance analysis (SF-BIA) in that it does not require the use of statistically derived, population-specific prediction equations. It has the potential advantage of not only measuring total body water (TBW), as does SF-BIA, but also offering the unique capacity to differentiate between ECW and ICW and, thus, to provide an estimate of BCM. This literature review was conducted to compare available BIS devices to multiple dilution for measuring fluid compartments or BCM in a number of populations. Variable results regarding the ability of BIS to measure absolute volumes, as well as the observation of wide limits of variation, make BIS problematic for individual assessment in the clinic, particularly in populations with abnormal fluid distribution or body geometry. BIS has been found to be more accurate for measuring changes in fluid volumes or BCM, particularly in post-surgical and human immunodeficiency virus (HIV)-infected individuals. It is certainly possible that population-specific adjustments may improve the accuracy of BIS for assessing individuals in the clinical setting; however, additional research and development is needed before the method can be accepted for routine clinical use.

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Evaluation of multifrequency bioimpedance spectroscopy for measurement of the extracellular water space in critically ill patients

Cited by 27 publications

References 4 publications

Extracellular Water and Blood Pressure in Adults with Growth Hormone (GH) Deficiency: A Genotype-Phenotype Association Study

Extracellular Water and Blood Pressure in Adults with Growth Hormone (GH) Deficiency: A Genotype-Phenotype Association Study

Validation of bio-impedance spectroscopy: Effects of degree of obesity and ways of calculating volumes from measured resistance values

Bioimpedance Spectroscopy for Clinical Assessment of Fluid Distribution and Body Cell Mass

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