One of the challenges in the treatment and management of lymphedema is the measurement of tissue composition, fluid amount or amount and skin condtion. In short, this is called body or tissue composition. These are important for for both the diagnoses, treatment and long term management of lymphedema.
Generally, this measurement has been through the use of a tape measure to simply gauge the amount of swelling the in lymphedematous limb versus the nonefffected limb.
Please be aware however, that despite the claims of its manufacturer, all the studies I could find still say it is “unproven” and needs additional clinical research. Other techniques that have been employed include the use of a volumeter which measures the water displacement of a limb. Another technique has been the use of a perometer. Total limb volume of fluid The central problems involving these techniques include inaccuracy, expense. A new device and technique has been developed by the Impedimed Company from Australia.
In biomedical engineering, bioimpedance is a term used to describe the response of a living organism to an externally applied electric current. It is a measure of the oppostion to the flow of that electric current through the tissues, the opposite of electrical conductivity. The measurement of the bioimpedance (or bioelectrical impedance) of the humans and animals has proved useful as a non-invasive method for measuring such things as blood flow (often referred to as bioimpedance plethysmography) and body composition ( known as bioelectrical impedance analysis or simply BIA).
In bioimpedance plethysmography, the measure is sometimes based on pulsatile blood volume changes in the aorta. Bioimpedance is relevant to the development of devices to measure cardiac output and circulating blood volume. Electrical conductivity can vary as a result of breathing. Because of this and other sources of variability, the reliability of bioimpedance for obtaining accurate data has been called into question. Nevertheless, the technique is used in both routine clinical medicine and research. BIA has found a much sounder footing and is the basis of a number of commercially available body composition analysers. See Bioelectrical impedance analysis for more details.(1)
Bioelectrical impedance analysis (BIA) is a commonly used method for estimating body composition. Since the advent of the first commercially available devices in the mid-1980s the method has become popular owing to its ease of use, portability of the equipment and its relatively low cost compared to some of the other methods of body composition analysis. It is familiar in the consumer market as a simple instrument for estimating body fat. BIA actually determines the electrical impedance, or opposition to the flow of an electric current, of body tissues, which can be used to calculate an estimate of total body water (TBW). TBW can be used to estimate fat-free body mass and, by difference with body weight, body fat.
Many of the early research studies showed that BIA was quite variable and it was not regarded by many as a providing an accurate measure of body composition. In recent years technological improvements have made BIA a more reliable and therefore more acceptable way of measuring body composition. Nevertheless it is not a “gold standard” or reference method. Like all assessment tools, the result that you get is only as good as the test you do. Although the instruments are straightforward to use careful attention to the method of use described by the manufacturer should be given. Simple devices to estimate body fat, often using BIA, are available to consumers as body fat meters. These instruments are generally regarded as being less accurate than those used clinically or in nutritional and medical practice.(1)
Lymphat Res Biol. 2009
Ward LC, Czerniec S, Kilbreath SL. 1 School of Chemistry and Molecular Biosciences, University of Queensland , St. Lucia, Brisbane, Australia .
Abstract Background: The aim was to assess the agreement between bioimpedance indices and inter-limb volume differences, as assessed by perometry, for assessment of unilateral arm lymphedema.
Methods: Impedance was measured in the arms of 45 women with lymphedema and a separate control group without lymphedema (n = 21). Arm volume was measured at the same time by perometry. The impedance indices, (ratio of impedances between limbs and the L-dex scores) were compared to the inter-limb volume differences using concordance correlation analysis.
Results: Impedance indices were highly correlated (r = 0.926) with the difference in arm volume measured by perometry.
Conclusions: Bioelectrical impedance analysis, although not providing a quantitative volume measurement of lymphedema, provides a measurement index that is highly correlated with quantitative measurements of the volume increase in limb size seen in lymphedema. The speed and ease of the impedance technique renders it a suitable alternative to perometry for the assessment of lymphedema.
Full Text Article:
Lymphat Res Biol. 2011
Gaw R, Box R, Cornish B. Source Queensland University of Technology, Brisbane, Australia.
Bioimpedance techniques provide a reliable method of assessing unilateral lymphedema in a clinical setting. Bioimpedance devices are traditionally used to assess body composition at a current frequency of 50 kHz. However, these devices are not transferable to the assessment of lymphedema, as the sensitivity of measuring the impedance of extracellular fluid is frequency dependent. It has previously been shown that the best frequency to detect extracellular fluid is 0 kHz (or DC). However, measurement at this frequency is not possible in practice due to the high skin impedance at DC, and an estimate is usually determined from low frequency measurements. This study investigated the efficacy of various low frequency ranges for the detection of lymphedema.
METHODS AND RESULTS:
Limb impedance was measured at 256 frequencies between 3 kHz and 1000 kHz for a sample control population, arm lymphedema population, and leg lymphedema population. Limb impedance was measured using the ImpediMed SFB7 and ImpediMed L-Dex(®) U400 with equipotential electrode placement on the wrists and ankles. The contralateral limb impedance ratio for arms and legs was used to calculate a lymphedema index (L-Dex) at each measurement frequency. The standard deviation of the limb impedance ratio in a healthy control population has been shown to increase with frequency for both the arm and leg. Box and whisker plots of the spread of the control and lymphedema populations show that there exists good differentiation between the arm and leg L-Dex measured for lymphedema subjects and the arm and leg L-Dex measured for control subjects up to a frequency of about 30 kHz.
It can be concluded that impedance measurements above a frequency of 30 kHz decrease sensitivity to extracellular fluid and are not reliable for early detection of lymphedema.
Czerniec SA, Ward LC, Lee MJ, Refshauge KM, Beith J, Kilbreath SL. Source Faculty of Health Sciences, University of Sydney, PO BOX 170, Lidcombe, Sydney, NSW 1825, Australia. Abstract PURPOSE: To determine if bioimpedance spectroscopy (BIS) could detect localised lymphoedema of the arm and to compare BIS measurements with equivalent measures of limb volume by perometry.
METHODS: Women with mild to severe upper limb lymphoedema (n = 29) and women with no history of lymphoedema (n = 11) participated. Commencing at the ulnar styloid of the wrist, 4 × 10 cm segment measurements were made of each arm using both BIS and perometry.
RESULTS: Average BIS inter-limb ratios for the total arm and each arm segment were higher than comparable perometry measures in women with lymphoedema, but similar to perometry measures for women without lymphoedema. Limits of agreement analysis showed that the mean difference between methods varied according to segment measured, ranging from 8.5% for the uppermost segment of the arm to 16.6% for the forearm segment just below the elbow. For all limb segments, there was a positive bias towards BIS measurements, which increased as lymphoedema severity increased.
CONCLUSION: BIS can be used for localised measurement of lymphoedema. Because it is specific to extracellular fluid, BIS is more sensitive to localised lymphoedema than perometry.
Lymphat Res Biol. 2008
Moseley A, Piller N. Department of Surgery and Lymphedema Assessment Clinic, Flinders University and Medical Centre, South Australia, Australia.
Abstract Background: Measuring the female breast, especially after breast cancer treatment, is problematic due to breast size, texture, and patient positioning. However, being able to accurately measure changes in the breast is important, as it may help in the earlier diagnosis and treatment of early breast edema and later lymphedema.
Methods: 14 women who had undergone breast conserving surgery for breast cancer (> 12 months ago) were recruited to assess the between subject reproducibility of tonometry and bioimpedance spectroscopy (BIS). With the participant supine, two repeat measurements of the resistance of the tissues to compression (tonometry) and fluid levels (BIS) of the treated and normal breast were taken for each of the four quadrants of the breast.
Results: The between subject reproducibility for both measurement techniques was high, with covariance ranging from 1.29% to 3.25% for tonometry and 0.20-0.86% for BIS.
Conclusions: The reliability of these two measurement techniques provides an opportunity for researchers and clinicians to easily quantify breast tissue and fluid changes which in turn may lead to the earlier diagnosis and targeted treatment of breast edema and lymphedema.
Breast Cancer Res Treat. 2008 Jun 18.
York SL, Ward LC, Czerniec S, Lee MJ, Refshauge KM, Kilbreath SL. Faculty of Health Sciences, University of Sydney, P.O. Box 170, East Street, 2141, Lidcombe, NSW, Australia.
Background The aims were to determine (i) whether single frequency bioimpedance analysis (SFBIA) is as accurate as bioimpedance spectroscopy (BIS) in measurement of extracellular fluid and (ii) whether change in extracellular fluid was specific to only the limb directly affected by surgery.
Methods Arms of the control (n = 28) and arm lymphedema group (n = 28) and legs of the leg lymphedema group (n = 16) were assessed with SFBIA. All four limbs in all participants were assessed with BIS. All measurements occurred in a single session.
Results BIS-measured ratios were highly concordant with those obtained with SFBIA (r © = 0.99, P < 0.001). Repeated measures ANOVA revealed that the ratio involving the lymphedema limb was different to the ratio of the non-oedematous limbs which was not significantly different to the arm or leg ratios of the control group.
Conclusions SFBIA is a simple accurate alternative to BIS for the clinical assessment of unilateral lymphedema. BIS discriminates those with clinical diagnosis of unilateral lymhoedema from those without the diagnosis.
Bioimpedance analysis (BIA) has become a widely accepted method for the determination of body composition due to its simplicity, speed and noninvasive nature. While BIA is recognised as one of the more reliable methods, not all devices or methods are able to achieve the level of accuracy required. The accuracy of a BIA device depends primarily on the number of frequencies at which measurements are taken. This is why the choice of instrument is so important.
Theory behind bioimpedance The science
BIA was first used over 30 years ago to measure the total water content of the body. The method involves passing an extremely low strength electrical current through the body and measuring the impedance to the flow of this current.
BIA is based on two key concepts
The fact that the body contains water and conducting electrolytes
When a current is passed through the body, the water-containing fluids primarily conduct the electrical current. Water is found both inside the cells, intracellular fluid (ICF) and outside the cells, extracellular fluid (ECF). At low frequency, current passes through the ECF space and does not penetrate the cell membrane. At high frequencies however the current passes through both the ICF and ECF (Figure 1).
That impedance of a geometrical system is related to conductor length, its cross sectional area and signal frequency
Based on these concepts a value for impedance can be calculated from a fixed strength current being passed through the body, which is inversely proportional to the amount of fluid. By appropriate choice of signal frequency, this can be made specific for extracellular fluid or for total fluid determinations.
The various types of bioimpedance include, single frequency BIA (SF-BIA), multiple frequency BIA (MF-BIA) and the latest advancement offered by ImpediMed, bioimpedance spectroscopy (BIS).
SF-BIA is generally performed at a frequency of 50 kHz. At this frequency the current passes through both the intracellular and extracellular fluid and consequently total body water (TBW) may be calculated. However, as the current passes through both intra and extracellular compartments, differences in intracellular fluid alone are unable to be determined .
SF-BIA relies on prediction equations and algorithms to calculate results . These algorithms have in general been determined from healthy subjects. The one algorithm is not suitable for all subjects. To be accurate devices will offer a choice of three on-board algorithms (General, Child and Obese) therefore improving the accuracy of measurement at 50 kHz.
MF-BIA involves taking impedance measurements at less than seven frequencies. These limited frequency devices employ empirical linear regression models to estimate subject results.
BIS takes measurements at 256 different frequencies and uses mathematical modelling to calculate the resistance at zero and infinite frequencies (R0 and Rinf respectively). These values are utilised through Hanai mixture theory to derive fat-free mass and fat mass. The determination of impedance at zero frequency is highly significant as this value represents the impedance of the ECF alone while establishing Rinf allows reliable prediction of the TBW .
There have been over 1600 publications on BIA in the English medical literature since 1990 . Medical researchers have been investigating the application of BIA & BIS technology in the areas of cancer, HIV, obesity, anorexia, renal failure and cirrhosis . There are many more possibilities for BIA, and in particular BIS.
1. Van Loan MD, et al. Use of bioimpedance spectroscopy (BIS) to determine extracellular fluid (ECF), intracellular fluid (ICF), total body water (TBW), and fatfree mass (FFM). pp. 6770. In Ellis, K. (ed.) Human Body Composition: In Vivo Measurement and Studies. Plenum Publishing Co., New York. 1993 2. Kyle UG, et al. (2004) ESPEN Guidelines. Bioelectrical impedance analysis - part 2: utilization in clinical practice. Clin. Nutr. 23:1430-53. 3. Kyle UG, et al. (2004) ESPEN Guidelines. Bioelectrical impedance analysis - part 1: review of principles and methods. Clin. Nutr. 23:1266-43. 4. Cornish BH, et al. (1993) Improved prediction of extracellular and total body water using impedance loci generated by multiple frequency bioelectrical impedance analysis. Phys. Med. Biol. 38:337-46.
Annals of Plastic Surgery. 58(5):541-543, May 2007. Warren, Anne G. BA *; Janz, Brian A. MD +; Slavin, Sumner A. MD *++; Borud, Loren J. MD *++
Background: Lymphedema, a chronic disfiguring condition resulting from lymphatic dysfunction or disruption, can be difficult to accurately diagnose and manage. Of particular challenge is identifying the presence of clinically significant limb swelling through simple and noninvasive methods. Many historical and currently used techniques for documenting differences in limb volume, including volume displacement and circumferential measurements, have proven difficult and unreliable.
Bioimpedance spectroscopy analysis, a technology that uses resistance to electrical current in comparing the composition of fluid compartments within the body, has been considered as a cost-effective and reproducible alternative for evaluating patients with suspected lymphedema.
Patients and Methods: All patients were recruited through the Beth Israel Deaconess Medical Center Lymphedema Clinic. A total of 15 patients (mean age: 55.2 years) with upper-extremity or lower-extremity lymphedema as documented by lymphoscintigraphy underwent bioimpedance spectroscopy analysis using an Impedimed SFB7 device. Seven healthy medical students and surgical residents (mean age: 26.9 years) were selected to serve as normal controls. All study participants underwent analysis of both limbs, which allowed participants to act as their own controls. The multifrequency bioimpedance device documented impedance values for each limb, with lower values correlating with higher levels of accumulated protein-rich edematous fluid.
Results: The average ratio of impedance to current flow of the affected limb to the unaffected limb in lymphedema patients was 0.9 (range: 0.67 to 1.01). In the control group, the average impedance ratio of the participant's dominant limb to their nondominant limb was 0.99 (range: 0.95 to 1.02) (P = 0.01).
Conclusions: Bioimpedance spectroscopy can be used as a reliable and accurate tool for documenting the presence of lymphedema in patients with either upper- or lower-extremity swelling. Measurement with the device is quick and simple and results are reproducible among patients. Given significant limitations with other methods of evaluating lymphedema, the use of bioimpedance analysis may aid in the diagnosis of lymphedema and allow for tracking patients over time as they proceed with treatment of their disease. (C) 2007 Lippincott Williams & Wilkins, Inc.
Lymphology. 2002 Dec
Moseley A, Piller N, Carati C. Lymphedema Assessment Clinic, Flinders Surgical Oncology Unit, Department of Public Health School of Medicine, Flinders Medical Centre, Bedford Park, Adelaide, South Australia. Amanda.Moseley@Flinders.edu.au
Secondary lymphedema of the legs is a common sequela of patients treated for cancer of the reproductive, gastrointestinal, urinary systems and melanoma. From a clinical and research perspective it is of utmost importance to use techniques that objectively quantify leg volume and fluid composition as an indicator of lymphedema severity and response to treatment. Two techniques often used in both the clinical and research setting are leg perometry and multi-frequency bioimpedance. Although both techniques have been extensively validated, this trial aimed to cross correlate both measurement techniques to ascertain whether each or both could be used reliably for measurement of leg lymphedema. These measurements were utilized throughout a clinical trial that assessed the effectiveness of a new home based treatment program in the form of the Sun Ancon Aerobic Exerciser. This machine delivered both elevation and passive exercise to the legs, with participants using the machine over a three week period during which time their leg volumes were measured using both perometry and bioimpedance. The results demonstrated that leg volume measurements decreased using both perometry and bioimpedance. The reduction in body extracellular fluid as measured by bioimpedance correlated well with a reduction in leg volume as measured by perometry. Bioimpedance also recorded a reduction in weight, which was correlated with the reduction in leg volume as measured by perometry. This trial confirms that perometry and bioimpedance were both effective in independently showing a reduction in leg lymphedema using the Aerobic Exerciser therapy, and that both methods can be reliably used to measure and follow leg lymphedema.
Lymphology. 2001 Mar
Cornish BH, Chapman M, Hirst C, Mirolo B, Bunce IH, Ward LC, Thomas BJ.
Centre for Medical & Health Physics, Queensland University of Technology, Australia. email@example.com
Multiple frequency bioelectrical impedance analysis (MFBIA) has previously been shown to provide accurate relative measures of lymphedema in the upper limb of patients (1). This paper reports the results of a three year prospective study to evaluate the efficacy of MFBIA to predict the early onset of lymphedema in patients following treatment for breast cancer. Bioelectrical impedance measurements and circumferential measurements of each upper limb were recorded in healthy control subjects (n = 60) to determine the normal range of the ratio (dominant/non-dominant) of extracellular and total limb volumes respectively. Patients undergoing surgery for the treatment of breast cancer were recruited as the study group; MFBIA and circumferential measurements were recorded pre-surgery, one month post-surgery and then at two month intervals for 24 months. One hundred and two patients were recruited into the study. Twenty patients developed lymphedema in the 24 months follow up period of this study. In each of these 20 cases MFBIA predicted the onset of the condition up to 10 months before the condition could be clinically diagnosed. Estimates of the sensitivity and specificity were both approximately 100%. At the time of detection by MFBIA, only one of the patients returned a positive test result from the total limb volumes determined from the circumferential measures. These results confirmed the suitability of the MFBIA technique as a reliable diagnostic procedure for the early detection of lymphedema.
PMID: 11307661 [PubMed - indexed for MEDLINE]
Ceska Gynekol. 2007 Aug
Halaska M, Strnad P, Chod J, Malá I, Nováková M, Stankusová H, Kolarík D, Feldmár P, Rob L. Gynekologicko-porodnická klinika 2. LF UK a FN Motol, Praha. firstname.lastname@example.org
OBJECTIVE: Lymphoedema is a severe postoperative complication after treatment of many malignancies. It is a pathological accumulation of extracellular water (ECW). Early diagnostic tool is needed. Multifrequency bioimpedance analysis (MFBIA) is a method for detection of changes in ECW. TYPE OF STUDY: Prospective study. Setting: Dept. of Obstetrics and Gynaecology of the 2nd Medical Faculty, Charles University, Prague. METHODS: We measured a control group of 72 women and a group of 74 patients undergoing a breast cancer surgery during 18 month after the surgery by MFBIA and circumferency. Characteristics of the patients were recorded. The detection of lymphoedema was done using MFBIA, circumferency measurement and upon the symptoms of the patients. RESULTS: The average age in the controll and tested group was 40,1 and 58,9 years. The average size of the tumour, grade and positivity if oestrogen receptors was 15,1 mm, 2,04 and 43%. In 23 patients (21%) complete lymphadenectomy was performed, in 51 patients (79%) a detection of sentinel lymph node was performed. Lymphoedema was detected in 8 women (11%). In these patients MFBIA detected lymphoedema 9 month earlier in total than other methods. CONCLUSION: MFBIA is a low-cost and precise method for the detection od early stage postoperative lymphoedema. We recommend to incorporate MFBIA into standard dispensatory plan of every patient combined with circumferency measurement. PMID: 17966613
Valerie Bougault, BS, Evelyne Lonsdorfer-Wolf, MD, PhD, Anne Charloux, MD, PhD, Ruddy Richard, MD, PhD, Bernard Geny, MD, PhD and Monique Oswald-Mammosser, MD, PhD
Correspondence to: Monique Oswald-Mammosser, MD, PhD, Service des Explorations Fonctionnelles Respiratoires et de l’Exercice, Hôpital Civil, BP 426, 67091 Strasbourg Cedex, France; e-mail: Monique.Oswald@chru-strasbourg.fr
Study objectives: The monitoring of cardiac output (CO) during exercise rehabilitation in patients with COPD, often including strenuous exercise, is advisable. Invasive methods (thermodilution, Fick method) are accurate, but for clinical routine use noninvasive CO estimation is required. We have shown that impedance cardiography (Physio Flow; Manatec Biomédical; Macheren, France) is reliable in COPD patients at rest and during a recumbent, light-intensity exercise. The aim of our study was to evaluate the validity of this noninvasive device in COPD patients during a maximal incremental exercise test (IET) and also during a strenuous intermittent work exercise test (IWET).
Design: Prospective comparative study of the impedance cardiograph vs the direct Fick method applied to oxygen.
Patients: Eight patients with moderate-to-severe COPD (59 ± 6 years old; FEV1, 38 ± 15% predicted; residual volume, 194 ± 64% predicted) [mean ± SD].
Measurements and main results: Forty-nine simultaneous measurements of CO by means of the direct Fick method (COFICK) and CO measured by the impedance cardiograph (COPF) were obtained during the IET, and 108 measurements were made during the IWET. The correlation coefficients between the two measurements were r = 0.85 and r = 0.71 for the IET and the IWET, respectively. COPF was higher than COFICK. The difference between the two methods was 3.2 ± 2.9 L/min during the IET and 2.5 ± 2.1 L/min during the IWET. Expressed as a percentage of the mean of the two measurements, this corresponded to 31 ± 21% and 25 ± 20%, respectively.
Conclusions: The relatively high number of values differing by > 20% precludes the use of impedance cardiography in clinical routine in such a difficult setting (hyperinflated patients and intense exercise).
Full Text Article:
Bilir SP, Dekoven MP, Munakata J.
Health Economics and Outcomes Research, IMS Health, 3 Lagoon Dr, Ste 230, Redwood City, CA.
Objectives: To estimate the economic outcomes associated with routine use of bioimpedance spectroscopy (BIS) to aid in the assessment of lymphedema following breast cancer (BC) treatment. Study Design: Budget impact analysis for a hypothetical payer, comparing a “current standard assessment methods” scenario with a hypothetical scenario in which BIS is used routinely. Methods: A payer-perspective decision model was built to calculate the 1-year budget impact of using either current standard methods or BISaided assessments for lymphedema in post-BC patients among a hypothetical payer population. Parameter values were obtained from the medical literature, including population characteristics, lymphedema incidence, resource utilization, and costs associated with assessments and treatment. Alternate scenario analysis incorporated incidence and associated costs of downstream infections and excess mental health care. Results: With 627 BC patients in a payer of 1M covered lives, base-case analysis shows cost savings of $315,711, or $0.03 per enrolled member per month (from the payer perspective), from implementation of BIS-aided assessments for lymphedema. Savings improved with consideration of sequelae (eg, infection, hospitalization). However, savings are reduced if specificity of current standard assessments improves by 25% (fewer unnecessary expensive treatments), or if cost of complex decongestive therapy falls by 25%. Sensitivity analysis showed that cost savings results were robust to changes in other model parameters. Conclusions: Over 1 year, BIS-aided assessment of lymphedema for patients following treatment for BC results in cost savings, even without considering potential cost savings associated with averted downstream sequelae.
Limb volume measurement: from the past methods to optoelectronic technologies, bioimpedance analysis and laser based devices. Oct 2010 International Angiology