what does bioelectrical impedance measure

There is disagreement amongst the limited research available, with only one study suggesting that BIA is suitable for assessing body composition in athletes [15], whereas other research suggests that body fat estimates are much higher in athletes when using the BIA method [16]. Although BIA was primarily used to determine changes in dialysis patients [2], it is a method now used to determine body composition across a range of populations, including athletes [2, 3], obese individuals [4, 5], and the general population [3]. Diminished cell count, membrane integrity and altered hydration status in critical illness can lead to changes in reactance and resistance, thereby decreasing PhA compared with healthy individuals [11,12]. Bioelectrical impedance is a test that looks at body composition. Effect of incorrect measures in the applied setting 38-43, 2004. However, it still requires extrapolation based on population references. In renal replacement therapy patients, a PhA cut-off of 4.6 has been shown to predict malnutrition, defined by protein--energy wasting [36,37]. It is unclear how many frequencies would be needed for a BIA device to be considered a BIS device, however, the principles behind how the devices work are the same. The lack of a validated equation for this population, combined with the large individual error reported in overweight and obese populations, suggests that BIA does not provide accurate body composition data for both single-measure and repeated measures. 417-424, 1986. J Crit Care 2017; 40:103107. We found that S-BIS measures accounted for ~85% of the age-related decrease in appendicular muscle power compared with only ~49% for dual-energy x-ray absorptiometry (DXA) measures. Bioelectric impedance is a method to measure the resistance of body tissues to the flow of a small electrical signal, and from that calculate the proportion of body fat. 15. do Amaral Paes TC, de Oliveira KCC, de Carvalho PP, Peres WAF. As hand-held and leg-to-leg methods may not account for the resistance of the lower- or upper body, respectively, it is logical to assume that hand-to-foot measurements may better reflect whole-body composition than the alternatives. A. Sedensky, Bioelectrical impedance during renal dialysis, Nephrology Dialysis Transportation, vol. 1968 ). 54. Although extensively validated, all techniques have limitations when applied during critical illness, because of costs, impracticality or radiation exposure. Hand-to-Foot BIA Zanella PB, vila CC, de Souza CG. Indeed, two studies found that low BIA/BIS-PhA corresponded to low CT- muscle mass (CT-MM) and muscle density in the critically ill [31,32]. Abstract: Bioelectrical impedance analysis (BIA) has been proposed for measuring fat-free mass, total body water, percent fat, body cell mass, intracellular water, and extracellular water: a veritable laboratory in a box. 885-892, 1998. hand-to-hand, leg-to-leg, supine vs. standing, etc.). 52. Bioelectrical impedance analysis (BIA) is a method for estimating body composition, in particular body fat and muscle mass, where a weak electric current flows through the body and the voltage is measured in order to calculate impedance (resistance) of the body. The reliability of BIA (the reproducibility of the observed value when the measurement is repeated) is also important to determine single-measurement precision, as well as the ability to track changes over time. Belgian Aging Muscle Society (BAMS). Search for Similar Articles Low standardized. Basso F, Berdin G, Virz GM, et al. Electrolyte-rich body water is highly conductive; therefore, muscles, having a higher water content, will encounter less resistance than relatively anhydrous tissues, such as fat. For example, an athlete may be singled-out for interventions to reduce their body fat based on their BIA assessment and normative values, yet other methods may suggest that their body composition is optimal. Standard measurement conditions may vary depending on the machine type (e.g. (2003) [8] stated that BIA is a suitable alternative for estimating body fat percentages when subjects are within a normal body fat range, however, there is a tendency for BIA to overestimate body fat in lean subjects and underestimate body fat in obese individuals. 4, pp. By the early 2020s smartwatches like the Samsung Galaxy Watch 4 contained built in BIAs. 25, no. WebFactors affecting bioelectrical impedance measurements in humans Eur J Clin Nutr. Our purpose is to improve the performance of athletes and teams around the world by simplifying sports science and making it practical. 70, pp. 56, pp. WebWhat does bioelectrical impedance spectroscopy (BIS) measure? A further study on obese populations [13] showed that individual disagreement in body fat measurement between BIA and the four-compartment model was high. WebBioelectrical impedance analysis (BIA) has been proposed for measuring fat-free mass, total body water, percent fat, body cell mass, intracellular water, and extracellular water: a Since the advent of the first commercially available devices in the mid-1980s the method has become popular owing to its ease of use and portability of the equipment. 6. Impedance is frequency sensitive; at low frequency the electric current flows preferentially through extracellular water (ECW) only while at high frequency the current can cross cell membranes and hence flows through total body water (TBW). Most body water is stored in muscle. The current is administered usually at the hands and feet and it [3][4], Dehydration is a recognized factor affecting BIA measurements as it causes an increase in the body's electrical resistance, so has been measured to cause a 5kg underestimation of fat-free mass i.e. However, there are several promising areas of research, concerning some of the most urgent clinical problems in intensive care, emphasizing the need to evaluate further the use and interpretation of bioimpedance in the intensive care setting. They speculated that changes in glycogen stores, and the loss of water bound to glycogen molecules, may affect BIA estimates of fat-free mass. The primary issues with BIA are: Sensor Placement You may search for similar articles that contain these same keywords or you may Bioelectrical impedance analysis-part II: utilization in clinical practice. Consequently, it is important that the correct equation is used for the population measured to ensure that any results are valid. Fat mass is then calculated as the difference between fat-free mass and body mass. 25, no. 3, pp. A pilot prospective cross-sectional study. However, a recent pilot-study comparing CT-MM at ICU admission and BIS-FFM adjusted for overhydration, using an algorithm developed for dialysis patients, found significant correlations and good agreements between the two techniques [32]. Sun et al. Accuracy. BIA also provides interesting theoretical ways for pharmacokinetic characterization and medication dosing through real-time appreciation of the changing body composition and volumes of distribution [47]. WebOther instruments measure impedance from hand to hand and allow (with a build-in software program in which weight, height, age and sex has to be entered) the reading of body fat Garlini LM, Alves FD, Kochi A, et al. Some studies published in 2015 showed that bioelectrical impedance analysis is a fairly accurate method for estimating body fat. 23. Despite being popular in many commercial gyms and within epidemiological research on group body composition, BIA does not appear to provide valid single- or repeated-measures of body composition for athletes. Bioelectrical Impedance Analysis in Monitoring of the Clinical Status and Diagnosis of Diseases. Assessment of muscularity by BIA is recommended by the Global Leadership Initiative on Malnutrition (GLIM) [39]. 463-467, 1993. Please try again soon. The criterion method for determining body composition is the four-compartment model (1] fat mass, 2] total body water, 3] bone mineral mass, and 4] residual mass), and should be used when assessing the validity of BIA measurements. Determination of gentamicin pharmacokinetics by bioelectrical impedance in critically ill adults. However, BIA did correctly identify patients with low CT-MM [31]. Superiority of BIS to the SF-BIA and MF-BIA techniques has not been proven in nonhealthy populations [13,4]. Many of the whole body bioimpedance instruments apply three approaches for impedance measurement: Deurenberg et al. 24. Samoni S, Vigo V, Resndiz LI, et al. Assessment of adult malnutrition and prognosis with bioelectrical impedance analysis: 10. 11. JPEN J Parenter Enteral Nutr 2017; 41:11311138. Effect of influenza-induced fever on human. The use of a single frequency was inaccurate for populations that did not have the standard body type. Parameters of bioelectrical impedance are good predictors of nutrition risk, length of stay, and mortality in critically ill patients: a prospective cohort study. Fetterplace K, Beach LJ, MacIsaac C, et al. Fluid distribution can also be assessed by BIA-derived ECW/TBW ratio. What is BIS? Individual error rates were greater than at baseline, with BIA underestimating fat mass by 7.5 kg in some subjects. Estimates of body composition using BIA are facilitated using empirically validated equations, which consider variables including gender, race, height, weight, and age. However, hydration of fat-free mass has been shown to rise to over 77 % with increased levels of body fat [22]. greater muscle mass, leaner, etc. A. Weststrate and J. G. A. J. Hautvast, Changes in fat-free mass during weight loss measured by bioelectrical impedance and by densitometry, American Journal of Clinical Nutrition, vol. In the ICU, real-time knowledge of body composition is advantageous to the individualization and optimization of fluid balances, nutrition regimes and medication dosing. Different types of BIA analysers are available, such as hand-held and leg-to-leg devices. [7] For example, moderate intensity exercise for 90120 minutes before BIA measurements causes nearly a 12kg overestimation of fat-free mass, i.e. Affiliation 1 Department of Human Nutrition, Agricultural University, Wageningen, The Netherlands. Clin Nutr 2004; 23:12261243. All TANITA body composition monitors Fiaccadori E, Morabito S, Cabassi A, Regolisti G. Body cell mass evaluation in critically ill patients: killing two birds with one stone. One main drawback of BIA is the incorporation of reference population values, for all but the raw parameters, which might not apply to the individual patient or population. Hand-held BIA The study showed that clinicians blinded to the BIVA results, achieved a mean CFB that was concordant with the prior BIVA classification (i.e. Several BIA parameters can potentially provide information on nutrition status and requirements. Clin Nutr 2020; 39:18091817. PhA is often considered a proxy for LBM. Current Opinion in Critical Care27(4):344-353, August 2021. The advantage of the multiple electrode devices is that body segments may be measured simultaneously without the need to relocate electrodes. A. Weststrate, I. Paymans and K. Van Der Kooy, Factors affecting bioelectical impedance measurements in humans, European Journal of Clinical Nutrition, vol. 35. The validity (the agreement between the true value and a measurement value) of body composition is key to determining the precision of BIA measurement, and its suitability for clinical use. In recent years[when?] Get new journal Tables of Contents sent right to your email inbox, http://creativecommons.org/licenses/by-nc-nd/4.0, Bioelectric impedance analysis for body composition measurement and other potential clinical applications in critical illness, Articles in PubMed by Hanneke Pierre Franciscus Xaverius Moonen, Articles in Google Scholar by Hanneke Pierre Franciscus Xaverius Moonen, Other articles in this journal by Hanneke Pierre Franciscus Xaverius Moonen, Clinical use of peripheral perfusion parameters in septic shock, Hemodynamic monitoring in cardiogenic shock, Intracranial pressure management: moving beyond guidelines, Mechanical circulatory support in the treatment of cardiogenic shock. 2). The need to standardise eating, exercise, and both acute and chronic hydration changes are clearly important to provide valid body composition estimations. WebBioelectrical impedance analysis (BIA) is a widely used method for estimating body composition, yet issues concerning its validity persist in the literature. [17], In 1983, Nyober validated the use of whole body electrical impedance to assess body composition.[18]. Evidence regarding other considerations to use and interpretation of BIA in the ICU setting are summarized in Table 2. An ECW/TBW ratio of more than 0.40 is considered indicative of overhydration of the extracellular compartment. This suggests that BIA may provide data that is not sufficiently accurate for the determination of individual body composition. Hydration and Glycogen Levels Equation models developed with. Basic Life Sci. Myatchin I, Abraham P, Malbrain MLNG. 50, pp. C. Lukaski, W. W. Bolonchuk, W. A. Siders and C. B. Body cell mass and fat-free mass provide potential use in estimation of metabolic rate, protein requirements and pharmacokinetics. 8. 4, pp. Bioelectrical impedance analysis (BIA) is used to analyze human body composition by applying a small alternating current through the body and measuring the WebBioelectrical Impedence measure of body composition. Evaluation of bioelectrical impedance analysis in critically ill patients: results of a multicenter prospective study. Logically, increased ECW is associated with a lower BCM/FFM-ratio. Similarly, athletes often take interest in their body fat percentages, and a false score indicating so-called negative changes in body fat may impact the confidence and compliance of an athlete. [24], In 2020 BIA became available for Apple Watch users with the accessory AURA Strap with built-in sensors.[25]. , used densitometry, anthropometry and The clinical benefit of BIA can be Influence of overhydration and rapid hydration shifts on BIA measurements, Influence of overhydration and rapid hydration shifts on predictive value of BIA parameters, Influence of body temperature on BIA measurements, Influence of osmotic shifts on BIA measurements, Reference values for BIA measurements in (subgroups of) critically ill patients, Cut-off values for outcome predictive qualities of BIA measurements in (subgroups of) critically ill patients, Validation of overhydration adjustment of derived parameters in (subgroups of) critically ill patients, Possible interference of BIA electrical current with electrical implants other than internal ICDs, Development and validation of predictive scoring systems including raw BIA parameters for (subgroups of) critically ill patients, Assessment of predictive qualities of BIA measurements for malnutrition, Development and validation of BIA-derived metabolic rate equations with gold-standard methods, External validation of method to predict glomerular filtration rate based on BIA-derived body cell mass (BIA-eGFR), Pharmacokinetic models using BIA-eGFR and effect on outcome parameters, Development and validation of equation for protein dosing to BIA-FFM and effect on outcome parameters, Exploring options to calculate derived BIA parameters omitting body weight and possibly height, Effect of BIVA/BIA-guided fluid management on ICU patient-centered outcomes, Input parameters, such as body height and weight are difficult to measure accurately in the ICU setting, Proxy measurements, such as ulna length, can be used to estimate height, Ideal body weight (IBW) cannot replace measured body weight as BIA input parameter, The Biasioli equation to calculate total body weight is based upon height but not weight and can be used to avoid the need for weighing, BIA is not validated in patients undergoing large and swift hydration shifts, BIA might be most reliable at ICU admission (before fluid resuscitation) or after ICU discharge when hydration status has stabilized, Altered BIA raw parameters because of hydration shifts do not devaluate their prognostic value, Overhydration distorts the normal distribution of water in the intracellular and extracellular space that is used to obtain derived BIA parameters and BIVA, A decline in PhA is related to the hydration score (TBW/FFM 100%), whereas body cell mass (BCM) and muscle mass (MM) decrease, suggesting that OH is mainly related to the extracellular compartment, Decrease of MM might be underestimated, as in case of muscle edema, FFM estimates might overestimate MM, as a constant FFM hydration of 0.73 is usually assumed, Interstitial edema is interpreted by BIVA as a state of OH, even if there is a state of relative intravascular hypovolemia, Derived values might be recalculated to a normalized ECW/TBW ratio, analogous to dialysis BIA software, Ascites, pleural effusion and urine retention theoretically influence BIA measurements, Segmental BIA can distinguish apparent trunk OH because of peritoneal dialysate, without influencing the extremities measurements, In cirrhosis patients, PhA is positively correlated with CT-derived MM, irrespective of ascites presence, Changing tissue electrolyte concentrations might influence raw BIA parameters, In chronic kidney disease patients, a 20% increase in Na+ as measured by 23Na-MRI, leads BIS to overestimate ECW by 1.22.4 l because of lower extracellular resistance, Fever might influence BIA measurements by reducing ECW, In ambulant Influenza persons, individuals (, BIA could interfere with electrical implants, leading manufacturers to advise against use whenever one is present, Multiple studies show that BIA could be safely performed in patients with ICDs. J Clin Pharmacol 1993; 33:562567. The measured phase angle therefore depends on several biological factors. modify the keyword list to augment your search. Jones SL, Tanaka A, Eastwood GM, et al. Lambell KJ, Earthman CP, Tierney AC, et al. The path of the electrical current may differ between this method and the hand-held method, and could potentially influence body composition results; though this issue is discussed later in the article. A study comparing sepsis patients with other critically ill patients found that PhA was negatively correlated with the APACHE-II score only in the nonsepsis group [21]. Many of the early research studies showed that BIA was quite variable and it was not regarded by many as providing an accurate measure of body composition. 5. 36. BIA-derived muscle mass appears a promising biomarker for sarcopenia, as it correlates well with CT-analysis. Safety of bioelectrical impedance analysis in patients equipped with implantable cardioverter defibrillators. Deurenberg, J. Protein targets are usually set to measured actual weight or calculated FFM. Clin Nutr 2004; 23:14301453. In the 1980s, Lukaski, Segal, and other researchers discovered that the use of a single frequency (50kHz) in BIA assumed the human body to be a single cylinder, which created many technical limitations in BIA. Several body composition techniques are available, based on assumptions of weight (hydrostatic weighing), water content (isotope dilution), volume (air displacement plethysmography), energy attenuation (Dual-Energy X-Ray Absorptiometry; DXA), and imaging techniques like computer tomography (CT) and MRI. Nevertheless, it is the 4-compartment model (4C) (DXA and MRI are acceptable alternatives) and not BIA that is regarded as the reference method in body composition analysis. SM-BIA can provide additional values, such as the appendicular skeletal muscle mass (ASMM), the sum of the four limbs muscle masses. The heterogeneity of the ICU populations studied might in part explain these discrepancies. The tetrapolar arrangement is preferred since measurement is not confounded by the impedance of the skin-electrode interface[26], In bioelectrical impedance analysis in humans, an estimate of the phase angle can be obtained and is based on changes in resistance and reactance as alternating current passes through tissues, which causes a phase shift. 405-411, 2007. Other factors which may impact the BIA measurement and should therefore also be standardised are [16]: The standardisation of hydration status is clearly of importance for BIA, as the method is reliant on estimations of total body water to ascertain fat-free mass. Barbosa-Silva MC, Barros AJ, Wang J, et al. First commercially available in the mid-1980s [1], bioelectrical Impedance Analysis (BIA) is an inexpensive and portable piece of body composition testing equipment. Bioelectrical impedance spectroscopy to estimate fluid balance in critically ill patients. WebImpedance methods can measure both total body water and extracellular fluid (ECF) in humans on the basis of the electrical properties of individual tissues. Moonen HPFX, van Zanten FJL, Driessen L, et al. One such limitation is the placement of the sensors, and their ability to give readings of total body composition. [citation needed], Simple devices to estimate body fat, often using BIA, are available to consumers as body fat meters. Fluid management in the intensive care unit: bioelectrical impedance vector analysis as a tool to assess hydration status and optimal fluid balance in critically ill patients. Day 3 volume status correlated with the duration of ventilation and ICU stay. Bioelectrical impedance methods are often classified by the number of frequencies used for analysis, with BIA often referring to single-frequency devices, whereas multiple-frequency devices are referred to as Bioelectrical Spectroscopy (BIS) as it uses a spectra of frequencies [5]. Low-frequency currents will not penetrate cell membranes, and as such will measure extracellular water impedance. Electrical impedance measurement (complex resistance in the presence of alternating current) is a useful tool for the investigation of the structural characteristics of solid materials and biological tissues, the changes of the latter reflect the physiological state of the tissue itself (Hayden et al. Wolters Kluwer Health [20], However, empirical equations were only useful in predicting the average population's body composition and was inaccurate for medical purposes for populations with diseases. However, later research found that this equation also failed to outperform the Tanita manufacturer equation, and resulted in wide limits of agreement [12]. It is important that these equations are validated using a total-body, water-based, four-compartment method, in an attempt to minimise the measurement error that is found when equations are based on the two-compartment model; such as hydrostatic weighing. Impedance consists of electric resistance and reactance. However, no recent attempts for predictive pharmacokinetic models using BIA in the ICU have been published. Hall, Body composition assessment of athletes using bioelectrical impedance measurements, Journal of Sports Medicine and Physical Fitness, pp. BIA assumes that the human body is composed of a series of cylinders, uniform in shape, length, cross-sectional area, and with constant conductivity. quantities of fat mass and fat-free mass) by running a small electrical current through the body. All rights reserved. A prospective study among 60 ventilated ICU patients found that a cumulative energy-deficit during ICU stay was independently associated with loss of BIS-FFM between inclusion and ICU discharge, as well as with ICU-acquired weakness [40]. Segmental BIA (SM-BIA) devices consider the body as five separate cylinders and use electrodes on all limbs, improving accuracy (Fig. There are a limited amount of comparisons between BIA and the reference four-compartment model in athletic populations. 6, pp. Sun et al., [7] validated BIA equations using the four-compartment model and reported that the equation was sufficient for use in epidemiological research studies to assess populations with normal levels of body composition. 59. The equation (the squared value of height divided by impedance measurements of the right half of the body) showed a correlation coefficient of 0.92 with total body water. 32. A further consideration for the use of BIA is the validity of its use in measuring changes in fat mass and fat-free mass over time, as this may indicate the efficacy of a nutritional or training intervention looking to manipulate body composition. These equations will have an error rate when compared to the hydrostatic weighing method, and thus, this error is multiplied by the original error of the reference method to provide a body composition assessment that may be somewhat distant from the actual values reported using a four-compartment model. The impedance of cellular tissue can be modeled as a resistor (representing the extracellular path) in parallel with a resistor and capacitor in series (representing the intracellular path, the resistance that of intracellular fluid and the capacitor the cell membrane). 58. 49, pp. WebConclusions Lean and fat mass calculated from BIA using published formulae produces plausible values and demonstrate good concordance between high BMI and high fat, but these differ substantially from the machine-generated values. This is possible simply because different bodily tissues (e.g. Leg-to-Leg BIA Berbigier MC, Pasinato VF, Rubin BA, et al. Deurenberg et al. However, this simplification overlooks possible asymmetry and the proportional difference between the trunk and the limbs. Dewitte A, Carles P, Joannes-Boyau O, et al. 4, pp. - It needs to know your age, height, gender, weight and activity level so will give accurate results. Adequate dosing of renally excreted drugs is challenging in critically ill patients because of changes in kidney function. 38. As such, a decrease of BCM resulting from critical illness is a marker for malnutrition. However, based upon derived FFM, these calculations are subject to caveats and have proven to be inferior to indirect calorimetry in several populations, albeit still more accurate than weight-based equations [42,43]. PA depends on cell membrane integrity and on body cell mass. Likewise, in critical illness PhA, ECW/TBW ratio and overhydration could be used to monitor the effect of fluid management strategies. Having said that, the development of an equation for athletic populations that are validated against the gold-standard four-compartment model may improve the validity of the measure. Similarly, hand-held instruments may only assess the body composition of the upper extremities. 4, pp. Multifrequency BIA devices (MF-BIA), therefore, provide a more direct portrayal of water compartments, making them more reliable in case of altered hydration status or electrolyte imbalances. 15, no. Various body composition parameters are derived from thereon, using regression analyses with multiple variables obtained through reference measurements. Research conducted by Jebb et al. Potentially, BIA-FFM could facilitate targeted protein dosing. WebDirect measurement of the bodys various compartments can Other articles where bioelectrical impedance is discussed: human nutrition: Body mass, body fat, and body WebBioelectric impedance analysis (BIA) is quick, noninvasive and relatively inexpensive, making it ideal for bedside use. 51. Association between multifrequency. 54-59, 2013. Saunders et al. Buch E, Bradfield J, Larson T, Horwich T. Effect of. A PhA greater than 6 is assumed normal in health, although PhA varies with sex (men) and age (because of loss of fat-free mass; FFM), and should ideally be related to a reference population, or converted to standardized PhA (SPhA) before comparing across populations [5,6]. WebThe measurement is an indication of resistance by fat tissue to an electrical current, a reliable test for measuring a persons body fat to lean muscle ratio. Age-related extracellular to total body water volume ratio (Ecv/TBW)--can it be used for dry weight determination in dialysis patients? In practice, the improvement in accuracy is marginal. We thank C.S. Ellegard LH, Petersen P, hrn L, Bosaeus I. Longitudinal changes in, 18. to maintaining your privacy and will not share your personal information without 15, pp. Kyle UG, Bosaeus I, De Lorenzo AD, et al. Authors P Deurenberg 1 , J A Weststrate, I Paymans, K van der Kooy. 11, no. Hui D, Dev R, Pimental L, et al. Bioelectrical Impedance Analysis (BIA) is able to make an estimation of body composition (e.g. 20. 36, no. Martinoli R, Mohamed EI, Maiolo C, et al. F. Kushner and D. A. Schoeller, Estimation of total body water in bioelectrical impedance analysis, American Journal of Clinical Nutrition, vol. 29. Razzera EL, Marcadenti A, Rovedder SW, et al. Clin Nutr ESPEN 2017; 18:4448. This detailed data can help healthcare professionals with early detection, assessment and interventions for chronic conditions. Similar to hand-held methods, leg-to-leg BIA involves an individual standing on scales with four electrodes situated at each footplate, with a low-level current passed through the lower body.
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