Indirect prediction of total body water content in healthy adult Beagles by single-frequency bioelectrical impedance analysis (original) (raw)
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BMC Research Notes, 2015
Background: Equations based on single-frequency bioelectrical impedance analysis at 50 kHz for determination of total body water content (TBW) have been previously validated in healthy non-sedated beagle dogs. We investigated whether these equations are predictive of TBW in various canine breeds by comparing the results of these equations with TBW values evaluated directly by deuterium oxide (D 2 O) dilution. Methods: Total body water content of 13 healthy adult pet dogs of various breeds was determined directly using D 2 O dilution and indirectly using previous equations based on values obtained with a portable bioelectric impedance device. Paired Student's t-tests were used to compare TBW obtained by single-frequency bioelectrical impedance analysis and D 2 O dilution. A p-value of <0.05 was considered statistically significant for all analyses. Results: Significant differences were observed between TBW determined by the reference method and the values obtained with both predictive equations. Conclusions: The proposed equations including single-frequency bioelectrical impedance analysis parameters validated at 50 kHz in healthy adult beagles need to be modified including morphological parameters such as body size and shape in a first approach. As in humans, morphological-specific equations have to be developed and validated.
The Journal of nutrition, 2002
KEY WORDS: • multifrequency bioelectrical impedance analysis • body composition • total body water • extracellular water • bioimpedance Multifrequency bioelectrical impedance analysis (MF-BIA 4 ) is a promising, noninvasive, rapid, safe, portable, reproducible, electrical method of assessing body composition that has the potential to quantify total body water (TBW), extracellular water (ECW) and intracellular water (ICW), and thereby enable prediction of the fat-free mass (FFM), fat mass (FM) and body cell mass (BCM) (1). To our knowledge, there have not been any reports evaluating the use of MF-BIA in cats. The purpose of this study was to develop the scaling constants and assess the effects of animal position, animal length measurement and electrode configuration on the volume prediction accuracy of the Hydra ECF/ICF Bioimpedance Analyzer (Model 4200; Xitron Technologies, San Diego, CA) compared to TBW estimated by deuterium water (D 2 O) space and ECW estimated by bromide (Br) space in healthy cats.
British Journal of Nutrition, 2004
The present study was performed to determine how equilibrated fluctuations in hydration affected the validity of bioelectrical impedance analysis (BIA) for body composition assessment. Total body water (TBW) expansion was induced by a 4 d endurance trial and the subsequent water loss was obtained over the recovery period. Twelve healthy men exercised on a cycle and treadmill alternately for 5 h/d over 4 d at moderate intensity. TBW, fat mass (FM) and fat-free mass (FFM) were assessed 3 d before the trial (control), and on the first and eighth day of recovery (R1 and R8 respectively). TBW was evaluated by 2 H dilution (TBW 2H ) as a reference method and by BIA (TBW BIA ) at 100 kHz at the same time. TBW 2H increased significantly between the control day and R1 by 1·87 (SD 1·11) litres (P¼ 0·005) and TBW BIA by 1·38 (SD 1·56) litres (P¼0·009). Both values returned to the control level on R8. For each period, TBW 2H and TBW BIA did not differ significantly and were correlated (r 2 0·85, P¼0·0004 for the control day; r 2 0·63, P¼ 0·03 for R1; r 2 0·75, P¼0·02 for R8). Plasma Na concentration and osmolality did not differ between the control day, R1 and R8. FFM gain (1208 (SD 1983) g) and FM loss (21168 (SD 906) g) between the control day and R1 were followed by a FFM decrease (2624 (SD 1281) g) and a FM increase (860 (SD 1212) g) between R1 and R8. As expected, these FFM and FM changes were significantly correlated with TBW variations. The present results provide evidence that BIA may be a useful method for estimating TBW when fluid shifts are equilibrated and electrolyte concentrations are unchanged. However, it is not a valid technique for assessing FM and FFM under these conditions.
Nutrition, 2005
Objectives: The first objective was to compare the accuracy of a foot-to-foot impedance meter with a multifrequency bioimpedance for measurements of fat-free mass (FFM) and fat mass (FM) using dual energy X-ray absorptiometry (DXA) as reference. The second objective was to validate measurements of extracellular water resistance and volume by the foot-to-foot impedance meter, using multifrequency bioimpedance as reference. Methods: This investigation was carried out in 60 volunteers 18 to 71 y of age. Impedance meters were a Tefal Bodymaster Vision (foot-to-foot) that featured a square wave signal and a Xitron Hydra 4200 (5 to 1000 kHz) by using the bioimpedance spectroscopic method. Results: Bland-Altman tests showed that FFM differences between Tefal and DXA data were 1.98 Ϯ 3.09 kg in men and Ϫ0.08 Ϯ 2.98 kg in women. Total body water was measured by the Xitron, and FFM as measured with the Xitron was calculated as total body water divided by 0.732. Mean differences between Xitron-measured and DXA-measured FFM were 2.37 Ϯ 3.03 kg for men and 2.84 Ϯ 2.40 kg for women, indicating a systematic underestimation by the Xitron of intracellular volume. Extracellular water resistances measured by Tefal were in good agreement with those measured by Xitron with electrodes pasted under the subject's feet (mean difference 8.5 Ϯ 31 ⍀). Extracellular water volumes were calculated from Tefal-measured extracellular water resistances by using a modified bioimpedance spectroscopic method and differed from those measured with Xitron by Ϫ0.03 Ϯ 0.66 L. Conclusion: Limits of agreement with DXA-measured FFM produced by the foot-to-foot impedance meter tested are too large for clinical measurements in individuals, but they are sufficient to assess FFM in groups of subjects and for home use. Our prototype was also capable of estimating extracellular water volume with a similar accuracy as multifrequency bioimpedance in normal subjects. Nutrition 21 (2005) 815-824 www.elsevier.com/locate/nut 0899-9007/05/$ -see front matter
British Journal of Nutrition, 1996
To investigate possible differences in the relationship between multi-frequency impedance and bodywater compartments (total body water (TBW) and extracellular water (ECW)) measured by dilution techniques in two European populations, we studied forty Italian (twenty male and twenty female) and forty-three Dutch (twenty-three male and twenty female) healthy subjects aged 1 9 4 1 years. The main differences in body build between the two groups were height, trunk length and the two ratios TBW/height and ECW/height. Population+pecific prediction formulas for ECW (at 1 kHz) and TBW (at 100 kHz) were developed. The prediction errors for ECW and TBW were about 0.6 and 1.5 kg respectively, (CV 4%) in both groups. Cross-validation analysis showed no significant error in the prediction of TBW but a slight error (range -4.9 to + 2.8 %) in the ECW prediction. The biases in both TBW and ECW were correlated with ECW/TBW (Y -0.44, P < 0.0005 and Y +0.52, P < 0.0005 respectively) in the two groups; the biases in ECW were also related to ECW/height (r 0-51, P < 0.001), TBW/height (r 0.25, P c 0.03, trunk length (r 0.36, P < 0-001) and Z1/Z,, (r 032, P < 0.01). In conclusion, the water distribution between the extra-and intracellular compartments emerged in the present study as the major cauw of error in the prediction of body water, and in particular of ECW from impedance measurements with a population-specific equation. Moreover, body build, expressed as TBW/height and ECW/height, had an impact on the bias. Body composition: Total body water : Multi-frequency bioimpedance In the average adult individual 5 0 4 0 % of body weight is water; the intracellular component of body water accounts for about 40% of body weight and the extracellular component for about 20 YO. Approximately 25 YO of the extracellular component is in the vascular system (plasma) and 75 % outside the blood vessels (interstitial fluid). In general, the extracellular water: total body water ratio (ECW/TBW) is higher in females and children. In healthy adults ECW/TBW increases with age from an average of 0.42 at age 30 years to 048 at 80 years (Forbes, 1987).
International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity, 1997
To validate the assessment of total body water (TBW) and extracellular water (ECW) by multi-frequency bioelectrical impedance. Twenty-five overweight but otherwise healthy subjects and 20 lean subjects. Cross-sectional. TBW and ECW were determined by dilution techniques. Prediction equations from the literature were used to calculate TBW and ECW from measured impedance at 100 and 50 kHz or 1 and 5 kHz, respectively. In 18 of the obese subjects, impedance was also measured with the electrodes placed at proximal sites. In lean and obese subjects, significant correlations were observed between the impedance index (H2/Z) at high frequencies with TBW (r = 0.90, P < 0.001 in lean and r = 0.80, P < 0.001 in obese subjects) and at low frequencies with ECW (r = 0.87, P < 0.001 and r = 0.77, P < 0.001 respectively). Proximal placement of electrodes slightly improved the correlation between the impedance index and TBW (from r = 0.83 to r = 0.90 at 50 kHz and from r = 0.85 to r = 0....
Journal of applied physiology (Bethesda, Md. : 1985), 2000
The purposes of this study were 1) to determine the compartmentation of body water in horses by using indicator dilution techniques and 2) to simultaneously measure bioelectrical impedance to current flow at impulse current frequencies of 5 and 200 kHz to formulate predictive equations that could be used to estimate total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV). Eight horses and ponies weighing from 214 to 636 kg had catheters placed into the left and right jugular veins. Deuterium oxide, sodium thiocyanate, and Evans blue were infused for the measurement of TBW, ECFV, and plasma volume (PV), respectively. Bioelectrical impedance was measured by using a tetrapolar electrode configuration, with electrode pairs secured above the knee and hock. Measured TBW, ECFV, and PV were 0.677 +/- 0.022, 0.253 +/- 0.006, and 0.040 +/- 0.002 l/kg body mass, respectively. Strong linear correlations were determined among measured variables that allow...
Comparison of Whole Body and Segmental Bioimpedance Methodologies for Estimating Total Body Water
Annals of the New York Academy of Sciences, 2006
We compared the whole body (WB) and segmental bioelectrical impedance analysis (BIA) methodologies in a group of healthy adults (n = 25). It has been suggested that the segmental methodology may overcome the difficulty in generating a single algorithm to predict total body water (TBW) in all groups whether healthy or not. We measured TBW, using D 2 O dilution, and WB and segmental BIA parameters. Cole-Cole analysis was used to determine the impedance at the characteristic frequency (Z c). The correlation between TBW (by D 2 O dilution) and segmental BIA measures (multiple regression, r = 0.90, p < 0.001, SEE = 3.1 L) was not significantly higher than the correlation between TBW (D 2 O dilution) and WB BIA measures (simple regression, r = 0.85, p < 0.001, SEE = 3.6 L). Others have observed this "lack of improvement" in a group of healthy subjects. The true value of the segmental BIA methodology may lie in applications involving groups with altered distributions of segmental and compartmental fluid.
Analytic assessment of the various bioimpedance methods used to estimate body water
Journal of applied physiology (Bethesda, Md. : 1985), 1998
Knowledge of patient fluid distribution would be useful clinically. Both single-frequency (SF) and impedance modeling approaches are proposed. The high intercorrelation between body water compartments makes determining the best approach difficult. This study was conducted to evaluate the merits of an SF approach. Mathematical simulation was performed to determine the effect of tissue change on resistance and reactance. Dilution results were reanalyzed, and resistance and parallel reactance were used to predict the intracellular water for two groups. Results indicated that the amount of intracellular and extracellular water conduction at any SF can vary with tissue change, and reactance at any SF is affected by all tissue parameters. Modeling provided a good prediction of dilution intracellular and extracellular water, but an SF method did not. Intracellular, extracellular, and total body water were equally predicted at all frequencies by SF resistance and parallel reactance. Extrace...