Comparison Of Bioimpedance Research Articles

Comparison of Bioimpedance and Underwater Weighing Body Fat Percentage Before and Acutely After Exercise at Varying Intensities.

Nickerson, BS, Esco, MR, Kliszczewicz, BM, and Freeborn, TJ. Comparison of bioimpedance and underwater weighing body fat percentage before and acutely after exercise at varying intensities. J Strength Cond Res 31(5): 1395-1402, 2017-The purpose of this study was to compare single-frequency bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS) with underwater weighing (UWW) body fat percentage (BF%) before (PRE), immediately post (IP), and 60 minutes post (60P) an acute bout of moderate and vigorous aerobic exercise. Nine men (age = 24.6 ± 3.7 years) volunteered for this study. Subjects visited the laboratory on 3 separate occasions. Testing included two 30-minute exercise sessions at 60 and 80% heart rate reserve (HRR) and a 30-minute control (CON) trial. The constant error (CE) was significantly higher for BIA at each time point and exercise session (CE = 3.0-4.9% for 60% HRR; 2.5-4.7% for 80% HRR). Conversely, BIS yielded a nonsignificant CE at each time point and exercise session (CE = -0.9 to 1.1% for 60% HRR; -0.3 to 1.2% for 80% HRR). The standard error of estimate (SEE) for both exercise sessions ranged from 2.7 to 3.1% and 3.8-4.3% for BIA and BIS, respectively. The 95% limits of agreement were narrower for BIA (60% HRR = ±5.5 to 7.8%; 80% HRR = ±6.6 to 8.5%) than BIS (60% HRR = ±8.4 to 9.4%; 80% HRR = ±8.1 to 10.2%). Results indicate that BIS can be used for mean group BF% in men at PRE, IP, and 60P time periods. However, BIA yielded a lower SEE and 95% limits of agreement than BIS. Therefore, BIA provides better individual estimates of BF% in men, but the CE should be taken into consideration.

0349 : Comparison of bioimpedance and X-ray micro-computed tomography (μCT) for total fat volume measurement in mice in vivo

Determination of adipose tissue proportion, as well as its spatial distribution, is a major part of metabolic syndrome assessment. Various methods, commonly used in mouse models, are either indirect measurement, invasive (destructive) or imaging techniques. Indirect measurement techniques, such as deuterium dilution (considered as gold standard) or bioimpedance are based on the measurement of body composition. They give access to the measure of total body fat, without distinction between visceral and subcutaneous fat volumes. Sacrifice and ex-vivo tissue weight allow both total fat measurement and partition between subcutaneous and visceral fat pad. It is a direct method that does not allow for longitudinal studies. Non-invasive micro-imaging modalities (magnetic resonance imaging and μCT) add, over others, the advantage of spatial localization of fat, in vivo. Of our study was to compare results of measurements of total body fat done by μCT and bioimpedance in mice. μCT was done using a dedicated in vivo imaging instrument (eXplore Vision 120, GE, USA) on 30 anesthetized mice. Each acquisition lasted approximately 12 min. Just after μCT, measurement of body composition was performed by bioimpedance (ImpediVET, ImpediMed, USA). The average value of total body fat by μCT is 5% higher than that obtained by bioimpedance. The standard deviation calculated from μCT measurements is lower than that obtained with bioimpedance (4.8% vs 6.8% respectively). The linear correlation of μCT and bioimpedance measure of total adipose tissue is moderate (r 2 = 0.55). It is the first time, to our knowledge, that a comparison of total fat volume measurement between μCT and bioimpedance is performed in mice. Surprisingly, the correlation appears not to be so trivial between the 2 methods. Before a deeper exploration, comparison of results obtained with these 2 methods should be made with caution.

Comparison of Bioimpedance and Clinical Methods for Dry Weight Prediction in Maintenance Hemodialysis Patients

Background: Bioelectrical impedance analysis (BIA) is a promising technique to evaluate dry weight. We compared the dry weight calculated by the three BIA equations Carlo Basile (CB) , Yanna Dou (YD) and the body composition spectroscopy (BCS) with clinical evaluation in maintenance hemodialysis (MHD) patients. Methods: The dry weight of enrolled MHD patients (DW_Clin) was evaluated under strict clinical surveillance. The whole-body resistances at 50 kHz, intra- and extracellular resistances were measured to calculate the dry weight (DW_CB, DW_YD and DW_BCS) using each of the three equations. Results: Neither DW_CB nor DW_BCS were statistically different compared to DW_Clin (DW_CB 63.2 ± 17.2 vs. 63.1 ± 16.1 kg; DW_BCS 62.8 ± 16.8 vs. 63.1 ± 16.1 kg, p > 0.05). DW_YD was significantly lower than DW_Clin (DW_YD 62.0 ± 16.1 vs. 63.1 ± 16.1 kg, p < 0.05). The bias between DW_CB and DW_Clin was the smallest among these three methods (ΔDW_CB -0.1 ± 1.4 kg; ΔDW_YD 1.1 ± 2.9 kg; ΔDW_BCS 0.3 ± 1.8 kg). Conclusion: The CB equations have better consistency with clinical dry weight in MHD patients.

Body composition following stem cell transplant: Comparison of bioimpedance and air-displacement plethysmography

ObjectiveThe aim of this study was to assess the agreement between detected changes in body composition determined by bioimpedance spectroscopy (BIS) and air-displacement plethysmography (ADP) among patients with cancer undergoing peripheral blood stem cell transplantation (PBSCT); and to assess the agreement of absolute values of BIS with ADP and dual energy x-ray (DXA). MethodsForty-four adult hematologic cancer patients undergoing PBSCT completed both BIS and ADP assessment at preadmission and at 3 mo after transplantation. A subsample (n = 11) was assessed by DXA at 3 mo after transplantation. Results were examined for the BIS instrument’s default setting and three alternative predictive equations from the literature. Agreement was assessed by the Bland-Altman limits of agreement analysis while correlation was examined using the Lin’s concordance correlation. ResultsChanges in body composition parameters assessed by BIS were comparable with those determined by ADP regardless of the predictive equations used. Bias of change in fat-free mass was clinically acceptable (all <1 kg), although limits of agreement were wide (more than ±6 kg). Overall, the BIS predictive equation accounting for body mass index performed the best. Absolute body composition parameters predicted by the alternative predictive equations agreed with DXA and ADP better than the BIS instrument’s default setting. ConclusionChanges predicted by BIS were similar to those determined by ADP on a group level; however, agreement of predicted changes at an individual level should be interpreted with caution due to wide limits of agreement.

Comparison of Bioimpedance and Dual-Energy X-Ray Absorptiometry for Measurement of Fat Mass in Hemodialysis Patients

Background: Fat mass (FM) is measured with dual-energy X-ray absorptiometry (DXA), but is expensive and not portable. Multifrequency bioimpedance spectroscopy (BIS) measures total body water (TBW), intracellular water (ICW) and extracellular water (ECW). FM is calculated by subtracting fat-free mass (FFM) from weight assuming a fractional hydration of FFM of 0.73. Hemodialysis (HD) patients, however, have nonphysiologic expansion of ECW. Our aim was to apply a model to estimate FM in HD patients and controls. Methods: We estimated the hydration of FFM in healthy subjects and HD patients with BIS (Impedimed multifrequency) assuming a hydration of 0.73 or using a model allowing ECW and ICW to vary, deriving a value for FM accounting for variances in ECW and ICW. FM was measured by DXA (Hologic Discovery W) in 25 controls and in 11 HD patients. We measured TBW, ECW and ICW with BIS and calculated FM using either weight - TBW/0.73 or with a model accounting for variations in ECW/ICW to estimate FM. Results: ECW/ICW was greater in HD patients than in controls (0.83 ± 0.08 vs. 0.76 ± 0.04; p = 0.001). FM (kg) measured by DXA or estimated from TBW using constant hydration or accounting for variations in ECW/ICW was not significantly different in controls or in HD patients. Values obtained by all methods correlated (p < 0.001) and none of the Bland-Altman plots regressed (r² = 0.00). FM measured by DXA and by BIS in both controls and HD patients combined correlated (r² = 0.871). Conclusion: Expansion of ECW in HD patients is statistically significant; however, the effect on hydration of FFM was insufficient to cause significant deviation from values derived using a hydration value of 0.73 within the range of expansion of ECW in the HD patient population studied here.

Comparison of bioimpedance and oesophageal Doppler cardiac output monitoring during abdominal aortic surgery

Abdominal aortic surgery is a high-risk procedure. Cardiac output monitoring allowing haemodynamic optimisation may reduce the complication rate. Minimally invasive, continuous techniques are preferable. Cardiac output using oesophageal Doppler has been validated in several studies, showing good agreement with the gold standard. The aim of this study was to assess the degree of correlation and agreement between cardiac output measured by oesophageal Doppler and bioimpedance obtained from an endotracheal tube.

A comparison of bioimpedance and continuous thermodilution measurement of cardiac output in ICU patients

A comparison of bioimpedance and continuous thermodilution measurement of cardiac output in ICU patients

Comparison of bioimpedance and thermodilution methods for determining cardiac output: Experimental and clinical studies

The changes in electrical bioimpedance caused by the blood flow through a thoracic segment may be measured using a series of electrodes placed at opposing ends of this segment. Cardiac output (CO) is calculated by computer as the change in bioimpedance over time. This study was performed to determine the accuracy of bioimpedance CO (CObi) compared with standard thermodilution CO (COtd) in an animal model and in patients. COtd was determined using a thermodilution CO computer, and CObi was calculated with a bioimpedance computer in 10 dogs at baseline and at 5-minute intervals following the injection of 7 mEq of calcium chloride. A high correlation between COtd and CObi was observed ( r = 0.91, p < 0.001) over a range of 2.5 to 6 L/min. Thirty-three paired observations using the CObi and COtd methods were performed in 10 patients following elective coronary artery bypass surgery. A significant correlation between the two methods was determined with a CO range of 2.1 to 7.8 L/min ( r = 0.77, p < 0.001). CObi became inaccurate with severe tachycardia (pulse, 180/min), low CO, or frequent arrhythmias. These results indicate that this technique provides a continuous noninvasive method of determining CO that is comparable with thermodilution techniques. The technique of CObi holds promise for widespread use when continuous and noninvasive monitoring of CO is necessary.

Comparison of bioimpedance and thermodilution methods for determining cardiac output: Experimental and clinical studies

The changes in electrical bioimpedance caused by the blood flow through a thoracic segment may be measured using a series of electrodes placed at opposing ends of this segment. Cardiac output (CO) is calculated by computer as the change in bioimpedance over time. This study was performed to determine the accuracy of bioimpedance CO (Cobi) compared with standard thermodilution CO (COtd) in an animal model and in patients. COtd was determined using a thermodilution CO computer, and CObi was calculated with a bioimpedance computer in 10 dogs at baseline and a 5-minute intervals following the injection of 7 mEq of calcium chloride. A high correlation between COtd and CObi was observed ( r = 0.91, p < 0.001) over a range of 2.5 to 6 L/min. Thirty-three paired observations using the CObi and COtd methods were performed in 10 patients following elective coronary artery bypass surgery. A significant correlation between the two methods was determined with a CO range of 2.1 to 7.8 L/min ( r = 0.77, p < 0.001). CObi became inaccurate with severe tachycardia (pulse, 180/min), low CO, or frequent arrhythmias. These results indicate that this technique provides a continuous noninvasive method of determining CO that is comparable with thermodilution techniques. The technique of CObi holds promise for widespread use when continuous and noninvasive monitoring of CO is necessary.