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ABSTRACT The accurate emulation of the electrical impedance of biological tissues is crucial for the development and validation of bioimpedance measurement devices and algorithms. This paper describes a digitally controllable impedance emulator capable of reproducing values representative of tissue bioimpedance in user‐specified resistance, reactance, and frequency ranges up to 1 MHz. The presented solution uses a 2R‐1C impedance model to emulate the impedance characteristics of a biological tissue. Specific selection of each element value in this model is achieved using analog multiplexers with low Ron$$ {R}_{on} $$ resistance. A MATLAB algorithm was developed for value estimation using target impedance requirements. An example design to emulate impedance from 1 kHz to 1 MHz with 10 Ω$$ \Omega $$ to 400 Ω$$ \Omega $$ resistance and −45Ω$$ -45\Omega $$ maximum reactance is provided. The nonideal behavior of this design was evaluated and compared against experimentally collected impedance measurements. Deviations of <1% were observed between experimental and theoretical resistances for values >50Ω$$ >50\Omega $$ up to 100 kHz (with approximately 5% deviations up to 1 MHz) and reactance deviations were also <1% up to 10 kHz. High frequency deviations are attributed to the parasitic capacitance in the realization of the design. The experimental results validate the design approach and realization for low frequencies. Overall, the innovation of the proposed approach is the control of both resistance and reactance for emulating electrical impedance representative of biological tissues. [ABSTRACT FROM AUTHOR]

Background: The prevalence of possible sarcopenia is notably high among maintenance hemodialysis (MHD) patients. Possible sarcopenia, defined as a decrease in muscle strength and/or somatic function, is an early and reversible condition between non-sarcopenic and sarcopenia, and early recognition and intervention for possible sarcopenia is important for preventing adverse outcomes and improving the quality of life of these patients. This study aimed to establish a simple and effective model for screening and identifying MHD patients at high risk of possible sarcopenia by using 50 kHz-Whole Body Phase Angle (PhA), with a specific focus on gender differences. Methods: This prospective cross-sectional study was conducted from September to December 2023 at the Wenjiang Hemodialysis Center in the Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China. A total of 244 MHD patients, including 130 males and 114 females, were enrolled. Data were collected prospectively, including demographic information and physical measurements. All participants provided informed consent before enrollment. Measurements were taken post-dialysis to ensure consistency. The whole-body phase angle was measured using the InBody S10 device, grip strength was measured using an electronic grip strength tester, and physical function was assessed by the Short Physical Performance Battery (SPPB). The Skeletal Muscle Index (SMI) was also calculated. Results: A total of 244 patients receiving hemodialysis were enrolled in this study. Among these, 109 patients were categorized as non-sarcopenic, 111 as having possible sarcopenia, and 24 as sarcopenic. The prevalence of sarcopenia among MHD patients is 9.8%, while the prevalence of possible sarcopenia is 45.5%. The receiver operating characteristic (ROC) curve analysis showed that for male patients, the AUC of PhA for predicting possible sarcopenia was 0.798, with a sensitivity of 80.36%, specificity of 69.70%, and a cutoff value of 6.20°. For female patients, the AUC of PhA was 0.701, with a sensitivity of 70.91% and specificity of 62.79%, and a cutoff value of 5.70°. Conclusions: PhA may be a useful and simple predictor of the risk of possible sarcopenia in MHD patients, and more research is needed to further promote the use of PhA in possible sarcopenia. [ABSTRACT FROM AUTHOR]

Background: Obesity remains a widely debated issue, often criticized for the limitations in its identification and classification. This study aims to compare two distinct systems for classifying obesity: body mass index (BMI) and body fat percentage (BFP) as assessed by bioelectrical impedance analysis (BIA). By examining these measures, the study seeks to clarify how different metrics of body composition influence the identification of obesity-related risk factors. Methods: The study enrolled 1255 adults, comprising 471 males and 784 females, with a mean age of 36 ± 12 years. Participants exhibited varying degrees of weight status, including optimal weight, overweight, and obesity. Body composition analysis was conducted using the TANITA Body Composition Analyzer BC-418 MA III device (T5896, Tokyo, Japan), evaluating the following parameters: current weight, basal metabolic rate (BMR), adipose tissue (%), muscle mass (%), and hydration status (%). Results: Age and psychological factors like cravings, fatigue, stress, and compulsive eating were significant predictors of obesity in the BMI model but not in the BFP model. Additionally, having a family history of diabetes was protective in the BMI model (OR: 0.33, 0.11–0.87) but increased risk in the BFP model (OR: 1.66, 1.01–2.76). The BMI model demonstrates exceptional predictive ability (AUC = 0.998). In contrast, the BFP model, while still performing well, exhibits a lower AUC (0.975), indicating slightly reduced discriminative power compared to the BMI model. Conclusions: BMI classification demonstrates superior predictive accuracy, specificity, and sensitivity. This suggests that BMI remains a more reliable measure for identifying obesity-related risk factors compared to the BFP model. [ABSTRACT FROM AUTHOR]

The aim of the study is to investigate the differences in body composition between differently trained men and women. This research included 159 participants (84 male and 75 female) divided into 5 groups according to activity level: PI - physically inactive, PA - physically active, SP - strength and power athletes, EA - endurance athletes, TS - team sports athletes. The testing procedure of measuring body composition was carried out by the use of bioelectrical impedance analysis (BIA, InBody 720). Of the statistical analysis, ANOVA and MANOVA were used. The results showed that there is a significant difference in body composition parameters between differently trained men and women (p = 0.000; F = 2.470; η² = 0.356, on average). Both in groups of men and women the biggest differences were observed between PI, EA and other groups (F = from 9.656 to -1.673, p = from 0.000 to 0.043; F = from 10.966 to 1.073, p = from 0.000 to 0.050, respectively). The results showed that every physical activity is beneficial from the aspect of body composition status and that the most crucial factor in improving body composition status is the regularity of physical activity. It has been shown that regular physical activity leads to a decrease in muscle fat and an increase in muscle mass and protein. Also, it has been shown that practicing a physical activity typical for endurance sports has the most significant positive impact on body composition status and leads to a significant decrease in body fat mass. [ABSTRACT FROM AUTHOR]

Despite BIA emerging as a clinical tool for assessing older adults, it remains unclear how to calculate whole-body impedance (Z), reactance (Xc), resistance (R), and phase angle (PhA) from segmental values using modern BIA devices that place electrodes on both sides of the body. This investigation aimed to compare both the whole-body and segmental device-generated phase angle (PhADG) with the phase angle calculated using summed Z, Xc, and R from the left, right, and combined sides of the body (PhACalc) and to compare bioelectric variables between sides of the body. A sample of 103 community-dwelling older adults was assessed using a 50 kHz direct segmental multifrequency BIA device. Whole-body PhACalc values were assessed for agreement with PhADG using 2.5th and 97.5th quantile nonparametric limits of agreement and Spearman's rho. Bioelectrical values between sides of the body were compared using Wilcoxon rank and Spearman's rho. A smaller mean difference was observed between PhADG and right PhACalc (−0.004°, p = 0.26) than between PhACalc on the left (0.107°, p = 0.01) and on the combined sides (0.107°, p < 0.001). The sum of Z, R, and PhACalc was significantly different (p < 0.01) between the left (559.66 ± 99.55 Ω, 556.80 ± 99.52 Ω, 5.51 ± 1.5°, respectively) and the right sides (554.60 ± 94.52 Ω, 552.02 ± 94.23 Ω, 5.41 ± 0.8°, respectively). Bilateral BIA values do not appear to be interchangeable when determining whole-body measurements. Present data suggest that using right-sided segmental values would be the most appropriate choice for calculating whole-body bioelectrical variables. [ABSTRACT FROM AUTHOR]

Heart-failure (HF) is a severe medical condition. Physicians need new tools to monitor the health status of their HF patients outside the hospital or medical supervision areas, to better know the evolution of their patients’ main biomarker values, necessary to evaluate their health status. Bioimpedance (BI) represents a good technology for sensing physiological variables and processes on the human body. BI is a non-expensive and non-invasive technique for sensing a wide variety of physiological parameters, easy to be implemented on biomedical portable systems, also called “wearable devices”. In this systematic review, we address the most important specifications of wearable devices based on BI used in HF real-time monitoring and how they must be designed and implemented from a practical and medical point of view. The following areas will be analyzed: the main applications of BI in heart failure, the sensing technique and impedance specifications to be met, the electrode selection, portability of wearable devices: size and weight (and comfort), the communication requests and the power consumption (autonomy). The different approaches followed by biomedical engineering and clinical teams at bibliography will be described and summarized in the paper, together with results derived from the projects and the main challenges found today. [ABSTRACT FROM AUTHOR]

Background: Heart failure (HF) represents a frequent cause of hospital admission, with fluid overload directly contributing to decompensations. Bioimpedance (BI), a physical parameter linked to tissue hydration status, holds promise in monitoring congestion and improving prognosis. This systematic review aimed to assess the clinical relevance of BI-based wearable devices for HF fluid monitoring. Methods: A systematic review of the published literature was conducted in five medical databases (PubMed, Scopus, Cochrane, Web of Science, and Embase) for studies assessing wearable BI-measuring devices on HF patients following PRISMA recommendations on February 4th, 2024. The risk of bias was evaluated using the ROBINS tool. Results: The review included 10 articles with 535 participants (mean age 66.7 ± 8.9 years, males 70.4%). Three articles identified significant BI value differences between HF patients and controls or congestive vs non-congestive HF patients. Four articles focused on the devices’ ability to predict HF worsening-related events, revealing an overall sensitivity of 70.0 (95% CI 68.8–71.1) and specificity of 89.1 (95% CI 88.3–89.9). One article assessed prognosis, showing that R80kHz decrease was related to all-cause-mortality with a hazard ratio (HR) of 5.51 (95% CI 1.55–23.32; p = 0.02) and the composite all-causemortality and HF admission with a HR of 4.96 (95% CI 1.82–14.37; p = 0.01). Conclusions: BI-measuring wearable devices exhibit efficacy in detecting fluid overload and hold promise for HF monitoring. However, further studies and technological improvements are required to optimize their impact on prognosis compared to standard care before they can be routinely implemented in clinical practice. [ABSTRACT FROM AUTHOR]

The monitoring of hemodynamic parameters, such as heart rate and blood pressure, provides valuable indications of overall cardiovascular health. It is preferable that such monitoring is non-invasive and in real time via an affordable, compact and small-scale device for maximum convenience. Numerous literature sources have exploited derivations of these parameters from photoplethysmogram (PPG) and electrical bioimpedance (EBI) signal measurements through the use of calculation algorithms of varying complexity. Compared to electrocardiogram (ECG), these measurement techniques have a merit of well-established practices of designing a wearable device that could conveniently be put on a wrist. The current paper provides a comprehensive review on the use of PPG and EBI measurement techniques in the context of hemodynamic parameter monitoring using a wearable device. A special emphasis is placed on the most basic hemodynamic parameter—heart rate—describing different algorithms of heart rate detection and monitoring. The last section provides an overview of commercially available and in-home wearable device technologies based on PPG and EBI measurements, their design challenges, and future prospects. [ABSTRACT FROM AUTHOR]

Introduction: Heart failure (HF) is associated with significant alterations in body composition, including malnutrition due to insufficient intake, chronic inflammation and increased energy expenditure. Identifying the prevalence of malnutrition and the risk of sarcopenia in patients with HF is crucial to improve clinical outcomes. Material and methods: This cross-sectional, single-center, observational study involved 121 outpatients diagnosed with HF. Nutritional status was assessed using the Mini Nutritional Assessment (MNA), the Malnutrition Universal Screening Tool (MUST), and the Subjective Global Rating (SGA). Sarcopenia was screened using the SARC-F (Strength, Assistance in walking, Rise from a chair, Climb stairs, Falls) questionnaire and diagnosed based on the European Working Group in Older People (EWGSOP2) criteria and functionality with the Short Performance Battery (SPPB) test. Malnutrition was diagnosed according to the Global Leadership Initiative on Malnutrition (GLIM) criteria. Results: The study found that 10.7% had cardiac cachexia and 45.4% of deceased patients had been in this condition (p = 0.002). Moderate-to-high risk of malnutrition was identified in 37.1%, 23.9%, and 31.4% of patients according to the MNA, MUST, and SGA tests, respectively. According to the GLIM criteria, 56.2% of patients were malnourished. Additionally, 24.8% of patients had a high probability of sarcopenia, and 57.8% were not autonomous according to SPPB. Patients with less than 30% quadriceps muscle contraction were at a high risk of sarcopenia. Conclusions: There is a high prevalence of malnutrition among outpatients with HF, which is associated with worse prognosis, increased risk of sarcopenia, and greater frailty. These findings underscore the importance of early nutritional and functional assessments in this population to improve clinical outcomes. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Dialysis adequacy is traditionally calculated from pre‐ and post‐hemodialysis session serum urea concentrations and expressed as the urea reduction ratio, or Kt/Vurea. However, with increasing hemodiafiltration usage, we wished to determine whether there were any differences between standard Kt/Vurea equations and directly measured spent dialysate urea clearance.Urea clearance was measured from collected effluent dialysate and compared with various other methods of Kt/Vurea calculation, including change in total body urea from measuring pre‐ and post‐total body water with bioimpedance and the Watson equation, by standard Kt/V equations, and online clearance measurements using effective ionic dialysance (OLC).We compared urea clearance in 41 patients, 56.1% male, mean age 69.3 ± 12.6 years with 87.8% treated by hemodiafiltration. Reduction in total body urea was greater when estimating changes in total body urea, compared to measured dialysate losses of 58.4% (48.5–67.6) vs 71.6% (62.1–78), p < 0.01. Sessional urea clearance (Kt/Vurea) was greater using the online Solute‐Solver program compared to OLC, median 1.45(1.13–1.75) vs 1.2 (0.93–1.4), and 2nd generation Kt/V equations 1.3 (1.02–1.66), p < 0.01, but not different from estimated total body urea clearance 1.36 (1.15–1.73) and dialysate clearance 1.36 (1.07–1.76). The mean bias compared to the Solute‐Solver program was greatest with OLC (−0.25), compared to second‐generation equations (−0.02), estimated total body clearance (−0.02) and measured dialysate clearance (−0.01).This study demonstrated that the result from equations estimating urea clearance indirectly from pre‐ and postblood samples from hemo‐ and hemodiafiltration treatments was highly correlated with direct measurements of dialysate urea clearance. [ABSTRACT FROM AUTHOR]

Background: In professional soccer, body composition analysis is crucial to assess preparation and optimize performance. Different playing positions have different physical demands, which can lead to variations in body composition. However, there are few studies on women's soccer that consider the playing position. This study aims to fill that gap by examining position-specific differences in anthropometric and body composition characteristics among Spanish professional female soccer players at the beginning and end of pre-season. Furthermore, it investigates the possible changes during the pre-season period between positions and correlates the data obtained from anthropometric equations with bioimpedance (BIA) measurements. Methods: Thirty-four female soccer players: 8 midfielders, 12 defenders, 11 forwards, and 3 goalkeepers (age: 23.06 ± 4.29 years, height: 164.15 ± 5.84 cm, weight: 58.39 ± 6.62 kg, and ∑6 skinfolds: 74.57 ± 18.48 mm) completed the study that lasted 4 weeks (pre-season) where they were measured anthropometrically and by bioimpedance twice. Results: Goalkeepers showed greater wingspan (176.60 ± 7.06 p < 0.05) compared to other positions. Regarding differences during pre-season, midfielders had the greatest decrease in ∑6 skinfolds compared to other positions (∆ −12.10 ± 5.69 p < 0.05). There was a correlation of % fat between Faulkner's equation and BIA (Pearson's r = 0.817). Conclusions: It seems that there are no significant differences in terms of positions and body composition, except for the wingspan and ankle diameter. During pre-season, midfielders are the ones who improve their body composition the greatest. The anthropometric equation for body fat that shows the highest correlation with BIA is Faulkner's equation, followed by Durnin's equation. [ABSTRACT FROM AUTHOR]

Summary: Management of obesity requires a multidisciplinary approach including physical activity interventions, which have significant impacts on overall health outcomes. Greater levels of lean muscle mass are significantly associated with improved health and reduced risk of comorbidities and should be preserved where possible when undertaking rapid weight loss. This article reports on the physical and functional outcomes achieved during a 12‐week intensive multidisciplinary intervention targeting obesity and evaluates correlations between body composition and functional outcomes. We additionally aimed to investigate the test–retest reliability and levels of agreement in body composition measurements using bioimpedance spectroscopy between seated and standing positions. Of the 35 participants included in analysis, significant differences were observed between baseline and post‐intervention measures. These included weight loss of 12.6 kg, waist circumference reduction of 10.5 cm, fat mass reduction by 2.9%, muscle mass increase by 1.6%, 54.5 m improvement in the 6‐minute walk test and 3.8 rep improvement in the 30‐second sit‐to‐stand test. No significant correlations were observed between physical and functional outcome measures. Excellent test re‐test reliability was observed in bioimpedance spectroscopy seated measurements (ICC >.9). Significant differences were observed between seated and standing bioimpedance spectroscopy measurements, however they are regarded as small differences in a clinical setting. [ABSTRACT FROM AUTHOR]

Lymphoedema tissue is characterised by excess free fluid and structural changes to the extracellular matrix (ECM) in the form of fibrotic and fatty deposition. These tissue characteristics are integral to the assessment of lymphoedema progression; however, clinicians and researchers often focus on changes in the free fluid, volume and function of lymphatic vasculature to inform practice. Subsequently, little is known about the effect of clinical interventions on lymphoedema tissue composition. This article presents a novel approach to classify lymphoedema tissue. The Localised Objective Characterisation Assessment of Lymphoedema (LOCAL) classification combines diagnostic and clinically meaningful objective assessment thresholds to infer lymphoedema pathophysiological changes in tissue layers. The LOCAL classification method was verified using data from fifteen women with unilateral breast cancer-related lymphoedema who were evaluated at three sites on each arm using high-frequency ultrasound (HFUS), bio-electrical impedance spectroscopy (BIS) and volume measurements. Participants exhibited an uneven distribution of volume between the proximal and distal segments of the arm (p = 0.023), with multiple tissue compositional categories observed across sites on the same limb (p < 0.001). The LOCAL method demonstrated utility in categorising a diverse range of lymphoedema tissue layer changes beyond what can be ascertained from whole-limb measures. [ABSTRACT FROM AUTHOR]

In an ageing society, the incidence of hard‐to‐heal wounds is rising. Chronic wound healing is a complex process, which requires specialised treatment. Clinical assessment of the wound is essential to establish care approaches but is usually based on visual evaluation and it remains challenging. Therefore, innovative quantitative methods for the assessment of chronic wounds are needed. We conducted a single‐centre observational study designed to assess the feasibility of a bioimpedance measurement method conducted with a multielectrode sensor array to monitor the wound healing process in patients with chronic wounds of venous, mixed venous–arterial and diabetic aetiology. In total, 104 measurements of bioimpedance were conducted in 18 ulcers during the study. Across all 7 patients analysed, the bioimpedance of the ulcers was consistently increasing as the wound surface was decreasing. The variables had significant (p < 0.001) and strong negative correlation (r = −0.86). We validated the feasibility of the bioimpedance measurement method for the monitoring of the wound healing process on the lower legs. It may be a promising quantitative method for monitoring the status of the wounds. However, long‐term measurements are needed to show the usability of the electrode dressing and bioimpedance measurement in the assessment of chronic wounds. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the impact of reductions in various body mass components on the erythrocyte oxidative status and glycemic state of people with obesity (PWO). Methods: A total of 53 PWO followed a six-month individualized low-calorie diet with exercise, during which anthropometric, biochemical, and oxidative parameters were measured. The participants were divided into groups based on weight (W), visceral fat area (VFA), total body water (TBW), and skeletal muscle mass (SMM) losses, as well as normoglycemia (NG) and hyperglycemia (HG). Results: Weight reduction normalized glycemia and influenced erythrocyte enzyme activity. Regardless of the tissue type lost (VFA, TBW, or SMM), glutathione peroxidase activity decreased in all groups, accompanied by an increase in glutathione reductase activity. Lipofuscin (LPS) and malondialdehyde (MDA) concentrations decreased regardless of the type of tissue lost. The α-/γ-tocopherol ratio increased in those losing >10% body weight, >15% VFA, and >5% TBW. In the NG group, compared to the HG group, there was a decrease in glutathione peroxidase and an increase in glutathione reductase, with these changes being stronger in the HG group. The LPS and MDA concentrations decreased in both groups. Significant correlations were observed between glucose reduction and changes in catalase, retinol, and α-tocopherol, as well as between VFA reduction and changes in vitamin E, L-LPS, and the activities of L-GR and L-GST. Conclusions: This analysis highlights the complex interactions between glucose metabolism, oxidative state, and erythrocyte membrane integrity, crucial for understanding diabetes and its management. This study shows the significant metabolic adaptability of erythrocytes in response to systemic changes induced by obesity and hyperglycemia, suggesting potential therapeutic targets to improve metabolic health in obese individuals. [ABSTRACT FROM AUTHOR]

Introduction: Hemodialysis patient groups have advocated reducing dialysis fatigue and symptoms. We investigated whether compartmental fluid shifts were associated with peri‐dialytic fatigue and symptoms. Methods: Sessional dialysis records of patients reporting both a short and delayed recovery (<1 h and ≥1 h) with corresponding bioimpedance measurements were reviewed. Results: One hundred and twenty‐four patients reported both short and delayed recovery times, mean age 66.0 ± 14.8 years, 66.1% male. Differences between sessions included higher distress thermometer [4 (1–6) vs. 3 (0–5)], fatigue [4 (0–9) vs. 2 (0–7)], total symptom scores [20.5 (12.3–34.5) vs. 16 (7–28)], change in extracellular water to total body water ratios between body compartments [right leg/left arm 2.36 (1.23–4.19) vs. 1.28 (0.12–2.01), all p < 0.01] with delayed recovery, and more hemodialysis than hemodiafiltration sessions (χ2 4.6, p = 0.02). Conclusion: Sessions with prolonged recovery times were associated with more peri‐dialytic symptoms, psychological distress, and hemodialysis mode, and greater changes in compartmental fluid shifts. [ABSTRACT FROM AUTHOR]

Abstract Background The prevalence of possible sarcopenia is notably high among maintenance hemodialysis (MHD) patients. Possible sarcopenia, defined as a decrease in muscle strength and/or somatic function, is an early and reversible condition between non-sarcopenic and sarcopenia, and early recognition and intervention for possible sarcopenia is important for preventing adverse outcomes and improving the quality of life of these patients. This study aimed to establish a simple and effective model for screening and identifying MHD patients at high risk of possible sarcopenia by using 50 kHz-Whole Body Phase Angle (PhA), with a specific focus on gender differences. Methods This prospective cross-sectional study was conducted from September to December 2023 at the Wenjiang Hemodialysis Center in the Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China. A total of 244 MHD patients, including 130 males and 114 females, were enrolled. Data were collected prospectively, including demographic information and physical measurements. All participants provided informed consent before enrollment. Measurements were taken post-dialysis to ensure consistency. The whole-body phase angle was measured using the InBody S10 device, grip strength was measured using an electronic grip strength tester, and physical function was assessed by the Short Physical Performance Battery (SPPB). The Skeletal Muscle Index (SMI) was also calculated. Results A total of 244 patients receiving hemodialysis were enrolled in this study. Among these, 109 patients were categorized as non-sarcopenic, 111 as having possible sarcopenia, and 24 as sarcopenic. The prevalence of sarcopenia among MHD patients is 9.8%, while the prevalence of possible sarcopenia is 45.5%. The receiver operating characteristic (ROC) curve analysis showed that for male patients, the AUC of PhA for predicting possible sarcopenia was 0.798, with a sensitivity of 80.36%, specificity of 69.70%, and a cutoff value of 6.20°. For female patients, the AUC of PhA was 0.701, with a sensitivity of 70.91% and specificity of 62.79%, and a cutoff value of 5.70°. Conclusions PhA may be a useful and simple predictor of the risk of possible sarcopenia in MHD patients, and more research is needed to further promote the use of PhA in possible sarcopenia.

The purpose of this pilot study was to determine if body orientation, skin treatment, joint angle, and shoulder arch movements affect localized bioimpedance spectroscopy (BIS) measurement. Nowadays, there are various wearable and portable impedance measurement tools in different shapes and sizes. Therefore, the body position and orientation of the subject during measurement may be of great importance for the comparability of the results. Ultrasound machine was used to measure the thickness of the skin layers and then bioimpedance measurements were performed for ten young men (age=23 ± 5) at room temperature (22°C) for different body orientations, skin treatments, joint angle, and shoulder arch movements. The results were analyzed using statistical methods and graphical presentation using Python and MatLab. Our observations indicate that there is a significant difference between standing straight up, supine and sitting positions. The results show that there is a significant difference between the two skin treatments (alcohol vs tape stripping). Moreover, joint angle and shoulder arch movements also have an impact on the impedance data. Therefore, to be able to control these factors can potentially improve the quality and comparability of the measured impedance data.

Bioelectrical impedance techniques have been useful in various applications, including body composition analysis, impedance plethysmography, impedance cardiography, lung ventilation, perfusion, and tissue characterization. Electrical impedance methods have also been useful in characterizing different foods like meat, fruits, and beverages. However, the temperature of tissue samples can change their dielectric properties, affecting their impedance. This research investigated the effects of temperature on the impedance of various biological tissues over the frequency range of 10 Hz to 5 MHz. Freshly excised animal tissues (lamb, cow, chicken), fish, fruits, and plants were considered as biological samples. The samples were placed in a test cell and submerged in a water bath heated by a hot plate to vary the temperature. Impedance measurements were conducted using a bioimpedance spectrometer in 2 °C steps within the temperature range of 20 °C to 50 °C. Impedance values decreased with increased temperature across all measurement frequencies for all biological samples. Curve fitting indicated that impedance decreased linearly with temperature, with a mean correlation coefficient of 0.972 for all samples. For all biological samples under investigation, the relative impedance change ranged from −0.58% to −2.27% per °C, with a mean and standard deviation of (−1.42±0.34) %/°C. On average, animal samples exhibited a higher relative temperature coefficient of −1.56% per °C (±0.41) across the frequency range, compared to −1.31% per °C (±0.26) for fruit and vegetable samples. Additionally, the relative temperature coefficient values were generally higher at lower frequencies than at higher frequencies. The findings of this research can be valuable for studies or biomedical applications involving variable tissue temperatures.

Summary: Objective: This work is aimed to develop a machine learning predictions of health status derived from bioimpedance measurements of adult healthy and cancer individuals. Methods: We conducted a pilot random study containing 2881 female (1220) and male (1661) patients ranging in age between 19 to 96 years old are studied. Among of them, 33 are diagnosed with cancer disease, the rest are healthy. After balancing the initial data, the data of interest contains 1.460 individuals ranging in age between 19 and 93 years old (734 female and 726 male), with 704 diagnosed with cancer and 756 healthy, respectively. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. The bioimpedance analyser (BioScan98®) is used, collecting fundamental bioelectrical and other parameters of interest. A classification model are performed, followed by a prediction of phase angle and body mass index. Results: The classification model reveal two robust parameters for predicting the health status, namely the impedance, the total body water and the phase angle with a 97%, 34% and 30 % of significance (respectively), with an area under the receiver operating characteristic curve of AUC = 1.00. The phase angle predictions agrees with previous reports of other type of pathologies, where higher phase angle values is ascribed to better health status and male have larger values than female. Recommendations regarding the capacitive reactance as a robust parameter to inferring health status is discussed. The cubic support vector machine model shows great accuracy predicting the nutritional status based on body mass index of both healthy and cancer patients. Conclusion: The classification, phase angle and body mass index predictive models developed in this work are of the great importance to assist the diagnosis, differentiating between healthy and cancer individual with great accuracy. Despite the moderate lack of body mass index association with cancer, this model can be used for prompt diagnosis.

There are various methods for cell growth monitoring. However, most of these methods have drawbacks, such as being invasive, not providing real-time results, or being costly. In this study, we present an alternate method of cell growth monitoring, which is low-cost, non-invasive, real-time, and uses Electrical Impedance Spectro-scopy (EIS). In this work, commercially available culture plates were fitted with custom tetrapolar electrodes, and mouse cells were cultured on them. The variation of culture media impedance, resulting from cell growth, proliferation and other metabolic activities, was recorded over a period of seven days. The results demonstrated an initial increase in impedance corresponding with the cell growth phase, followed by a decrease during the cell death (apoptosis) phase, as confirmed by microscope images. Overall, the results show that our method to monitor cell growth using tetrapolar electrodes is promising and can be further refined for related applications.

ntroduction: In areas with limited access to healthcare systems, Resting Energy Expenditure (REE) estimation is performed using predictive equations to calculate an individual’s caloric requirement. One problem is that these equations were validated in populations with different characteristics from those in Latin America, such as race, height, or body mass, leading to potential errors in the prediction of this parameter. Objective: To determine the REE using predictive formulas compared with bioimpedance in Peruvians. Materials and methods: A comparative analytical cross-sectional study with secondary database analysis of the CRONICAS cohort. Results: we worked with a total of 666 subjects. The Mjeor equation was the one with the highest rating of 0.95, a lower mean absolute percentage error (MAPE) of 4.69%, and equivalence was found with the REE values. In the multiple regression, it was observed that the Mjeor equation was the one that least overestimated the REE, increasing 0.77 Kcal/day (95% CI: 0.769-0.814; p

The detection of meat quality defects can involve both subjective and objective methods. PSE-like meat is linked to a common pork defect and can be caused by rapid post-mortem damage of muscle fibers. This damage can again be linked to various factors, such as a low ultimate pH or a higher slaughter weight. PSE-like defects are characterized by discoloration, structural damage, and excessive moisture loss. However, the lack of suitable instrument-based methods makes the detection of PSE-like defects difficult, and subjective methods typically suffer from poorer reproducibility. The objective of this study was to establish how subjective visual evaluation correlates with electrical impedance spectroscopy and with traditional quality parameters. To do so, visual scoring was performed together with measurements of bioimpedance, color, and pH in two ham muscles (Adductor, Semimembranosus) for 136 animals 24-hours post-mortem. When comparing with visual scoring, Pearson correlation analysis shows the strongest correlation for bioimpedance (Py, r = −0.46, R2 = 21%), followed by pHu (r = 0.44, R2 = 19%). When using all five quality measures, i.e., Py, pHu, and CIELAB L* a* b*, the multivariate regression model had a prediction error of 0.76 for the visual scores. This was close to the error describing the subjective bias of visual scoring, more specifically the prediction error between the two observers (0.85). In all, Py showed the strongest correlation among instrument-based quality tests and alone may be used for predicting pork ham structural defects, i.e., as an instrument-based alternative for subjective, visual scoring. However, an instrument that combines Py with pH and/or L*a*b* would improve the prediction of PSE-like quality defects.

Methods for assessing post-mastectomy edema: bioimpedance and upper extremity lymphedema index (UEL index) are non-invasive, highly sensitive and easily feasible diagnostic methods, suitable for predicting the prospects of surgical treatment and analyzing the dynamics of edema. The purpose of the study was to study UEL index indicators and bioimpedance data at different stages of upper extremity lymphedema. Material and methods. The study included 64 patients with post-mastectomy edema who underwent bioimpedance, measurement of the circumference of the upper extremity and calculation of the UEL index. Results. The upper extremity lymphedema index and bioimpedance parameters (fluid volume in the limb and the ratio of extracellular fluid to total fluid volume) characterizing the liquid component significantly increased at stages II and III of lymphedema in comparison with the control group. a statistically significant correlation was revealed between the upper limb lymphedema index and bioimpedance parameters (R=0.41) and (R=0.49), respectively. Conclusion. Bioimpedance parameters and values of the upper extremity lymphedema index can be interchangeable. The reliability and high sensitivity of these methods for assessing post-mastectomy edema allows us to obtain quantitative criteria for evaluating the liquid component at different stages of lymphedema.

The body composition of cultured live large yellow croaker (Pseudosciaena crocea) is extremely difficult to detect. In order to solve this problem, we analyzed the relationship between the impedance measured at 2, 5, 20, 50, 100 kHz for the dorsal and ventral muscles of live large yellow croaker and their key components (protein, fat and moisture). The optimal models (r = 0.830–0.922, P < 0.001) for non-destructive evaluation of the muscle protein and water contents as well as the fat content in live fish was established using the impedance at 2 and 100 kHz frequencies, and their accuracy was verified by experiments (r ≥ 0.900). The correlation among muscle composition, microstructure and impedance indicated that the average area of muscle fiber increased with increasing protein content and decreasing moisture content and was positively correlated with the impedance at 2 kHz; in contrast, the density of muscle fiber and the area of extracellular space decreased with increasing protein content and decreasing moisture content and was negatively correlated with the impedance at 2 kH. The diameter and volume of adipocytes increased with the deposition of fat, and had a significant relationship with the impedance at 100 kHz. This study can rapidly evaluate the composition of fat, protein, water and so on of cultured live large yellow croaker by using biological impedance, and clarify the internal reasons for predicting the composition of live fish by impedance. The findings of this study can help aquaculture enterprises with targeted breeding and and help consumers to choose the optimal products.

Background Obesity, especially abdominal obesity, is strongly correlated with metabolic and other health risks. Diagnosis and assessment of obesity is important in clinical and routine preventive practice. From the point of view of risk, it is necessary to distinguish not only the area of fat tissue accumulation, but also its type. Objective The aim of the study was to use a new portable abdominal bioimpedance analyzer, which is intended for the area of abdominal adipose tissue, as part of the evaluation of the body structure of a selected group of volunteers with a focus on the differentiation of subcutaneous and visceral adipose tissue and to assess its usefulness in practice. Material and Methods Body composition was analyzed using a portable abdominal bioimpedance analyzer Yscope (PA-BIA) in combination with a bioimpedance device InBody 970 (high-frequency bioelectrical impedance/HF-BIA). Eighty-three volunteers at the age of 24.92±7.24 years with representation of both sexes participated in the study. Results Abdominal fat did not differ significantly between the sexes, women reached an average value of 2.01±1.14 kg, men 2.22±1.60 kg (p>0.05). Gender differentiation was manifested in the case of visceral fat (p

Abstract Objective The search for other indicators to assess the weight and nutritional status of individuals is important as it may provide more accurate information and assist in personalized medicine. This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy younger volunteers from Southern Cuba Region. Methods A pilot random study at the Pediatrics Hospital was conducted. The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 776 female and male volunteers are studied. Along the age and sex in the cohort, volunteers with class I obesity, overweight, underweight and with normal weight are considered. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. The bioimpedance analyser is used, collecting fundamental bioelectrical and other parameters of interest. A classification model are performed, followed by a prediction of the body mass index. Results The results derived from the classification leaner reveal that the size, body density, phase angle, body mass index, fat-free mass, total body water volume according to Kotler, body surface area, extracellular water according to Kotler and sex largely govern the weight status of this population. In particular, the regression model shows that other bioparameters derived from impedance measurements can be associated with weight status estimation with high accuracy. Conclusion The classification and regression predictive models developed in this work are of the great importance to assist the diagnosis of weigh status with high accuracy. These models can be used for prompt weight status evaluation of younger individuals at the Pediatrics Hospital in Santiago de Cuba, Cuba.

Abstract Background Lumbar puncture (LP) is an important yet difficult skill in medical practice. In recent years, the number of LPs in clinical practice has steadily decreased, which reduces residents’ clinical exposure and may compromise their skills and attitude towards LP. Our study aims to assess whether the novel bioimpedance needle is of assistance to a novice provider and thus compensates for this emerging knowledge gap. Methods This randomized controlled study, employing a partly blinded design, involved 60 s- and third-year medical students with no prior LP experience. The students were randomly assigned to two groups consisting of 30 students each. They performed LP on an anatomical lumbar model either with the conventional spinal needle or the bioimpedance needle. Success in LP was analysed using the independent samples proportion procedure. Additionally, the usability of the needles was evaluated with pertinent questions. Results With the conventional spinal needle, 40% succeeded in performing the LP procedure, whereas with the bioimpedance needle, 90% were successful (p

Abstract Objective The search for other indicators to assess the weight status of individuals is important as it may provide more accurate information and assist in personalized medicine.This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy infant juvenile cohort from the Southern Cuba Region, Santiago de Cuba. Methods The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 393 female and male infant and juvenile individuals are studied. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. A classification model are performed, followed by a prediction of other bioparameters influencing the weight status. Results The results obtained from the classification model indicate that fat-free mass, reactance, and corrected resistance primarily influence the weight status of the studied population. Specifically, the regression model demonstrates that other bioparameters derived from impedance measurements can be highly accurate in estimating weight status. Conclusion The classification and regression predictive models developed in this work are of the great importance for accessing to the weigh status with high accuracy of younger individuals at the Oncological Hospital in Santiago de Cuba, Cuba.

Muscle dysfunction and muscle atrophy are common complications resulting from Chronic Obstructive Pulmonary Disease (COPD). The evaluation of the peripheral muscles can be carried out through the assessment of their structural components from ultrasound images or their functional components through isometric and isotonic strength tests. This evaluation, performed mainly on the quadriceps muscle, is not only of great interest for diagnosis, prognosis and monitoring of COPD, but also for the evaluation of the benefits of therapeutic interventions. In this work, bioimpedance spectroscopy technology is proposed as a low-cost and easy-to-use alternative for the evaluation of peripheral muscles, becoming a feasible alternative to ultrasound images and strength tests for their application in routine clinical practice. For this purpose, a laboratory prototype of a bioimpedance device has been adapted to perform segmental measurements in the quadriceps region. The validation results obtained in a pseudo-randomized study in patients with COPD in a controlled clinical environment which involved 33 volunteers confirm the correlation and correspondence of the bioimpedance parameters with respect to the structural and functional parameters of the quadriceps muscle, making it possible to propose a set of prediction equations. The main contribution of this manuscript is the discovery of a linear relationship between quadriceps muscle properties and the bioimpedance Cole model parameters, reaching a correlation of 0.69 and an average error of less than 0.2 cm regarding the thickness of the quadriceps estimations from ultrasound images, and a correlation of 0.77 and an average error of 3.9 kg regarding the isometric strength of the quadriceps muscle. [ABSTRACT FROM AUTHOR]

Bioimpedance is a diagnostic sensing method used in medical applications, ranging from body composition assessment to detecting skin cancer. Commonly, discrete-component (and at times integrated) circuit variants of the Howland Current Source (HCS) topology are employed for injection of an AC current. Ideally, its amplitude should remain within 1% of its nominal value across a frequency range, and that nominal value should be programmable. However, the method's applicability and accuracy are hindered due to the current amplitude diminishing at frequencies above 100 kHz, with very few designs accomplishing 1 MHz, and only at a single nominal amplitude. This paper presents the design and implementation of an adaptive current source for bioimpedance applications employing automatic gain control (AGC). The "Adaptive Howland Current Source" (AHCS) was experimentally tested, and the results indicate that the design can achieve less than 1% amplitude error for both 1 mA and 100 µA currents for bandwidths up to 3 MHz. Simulations also indicate that the system can be designed to achieve up to 19% noise reduction relative to the most common HCS design. AHCS addresses the need for high bandwidth AC current sources in bioimpedance spectroscopy, offering automatic output current compensation without constant recalibration. The novel structure of AHCS proves crucial in applications requiring higher β-dispersion frequencies exceeding 1 MHz, where greater penetration depths and better cell status assessment can be achieved, e.g., in the detection of skin or breast cancer. [ABSTRACT FROM AUTHOR]

In this study, we evaluated Electrical Impedance Spectroscopy (EIS) as a monitoring tool of the physiological state of Bryopsis, Cystoseira, Stypopodium, Cladophora, Taonia, Padina, Ulva and Sargassum tissues. We analyzed the electrical response differences in the EIS between species and in the same seaweed tissue before and after electroporation. Electroporation using high voltage pulsed electric field (PEF) treatment was used as a model for cell disruption affecting the tissue physiology without being noticeable to the naked-eye. Significant differences in all the seaweeds were observed before and after electroporation. We found that seaweed species with smaller and rounder cells have a clearer dispersion profile (around a frequency of 10–100 kHz) compared to the dispersion profile of seaweed with larger cells with unround form. Those results suggest that EIS could be used as a fast non-invasive monitoring technique of the changes in the physiology of seaweeds. [ABSTRACT FROM AUTHOR]

The view of embodied emotion believes that emotions are the emotions of the body. While emotion-specific patterns of self-reported bodily sensation have been previously reported, the physiological bodily representation across emotions remains to be addressed. The present study aimed to investigate the effectiveness of multi-site bodily electrodermal representations of emotions. A multi-channel electrodermal measurement device was designed to record electrodermal activities from nine body sites (neck, back, chest, bilateral abdomen, bilateral wrist, and bilateral ankle) from thirty-six college students (all male), while they were presented with a series of emotional pictures. Using the integral skin conductance response feature and a random forest classification method, the classification of high and low arousal levels achieved an average classification accuracy of 80.4 ± 8.1%, and the classification of positive, neutral, and negative states reached an average classification accuracy of 76.4 ± 10.2%. The classification models for arousal and valence were found to rely on distinct bodily representations. Meanwhile, the classification results of multi-site measurement were significantly better than single-site results. Our findings for the first time illustrate the bodily electrodermal representations of emotion and suggest the feasibility of affective computing using bodily electrodermal signals. [ABSTRACT FROM AUTHOR]

Conventional dry electrodes often yield unstable results due to the presence of parasitic capacitance between the flat electrode surface and the non-uniform skin interface. To address this issue, a gel is typically placed between the electrodes to minimize parasitic capacitance. However, this approach has the drawbacks of being unsuitable for repeated use, limited lifetime due to gel evaporation, and the possibility of developing skin irritation. This is particularly problematic in underserved areas since, due to the cost of disposable wet electrodes, they often sterilize and reuse dry electrodes. In this study, we propose a method to neutralize the effects of parasitic capacitance by attaching high-value capacitors to the electrodes in parallel, specifically when applied to pulse wave monitoring through bioimpedance. Skin capacitance can also be mitigated due to the serial connection, enabling stable reception of arterial pulse signals through bioimpedance circuits. A high-frequency structure simulator (HFSS) was first used to simulate the capacitance when injection currents flow into the arteries through the bioimpedance circuits. We also used the simulation to investigate the effects of add-on capacitors. Lastly, we conducted preliminary comparative analyses between wet electrodes and dry electrodes in vivo with added capacitance values ranging from 100 pF to 1 μF, altering capacitance magnitudes by factors of 100. As a result, we obtained a signal-to-noise ratio (SNR) that was 8.2 dB higher than that of dry electrodes. Performance was also shown to be comparable to wet electrodes, with a reduction of only 0.4 dB using 1 μF. The comparative results demonstrate that the addition of capacitors to the electrodes has the potential to allow for performance similar to that of wet electrodes for bioimpedance pulse rate monitoring and could potentially be used for other applications of dry electrodes. [ABSTRACT FROM AUTHOR]

Bioimpedance sensing is widely used across a spectrum of biomedical applications. Among the different system architectures for measuring tissue impedance, synchronous detection or demodulation (SD) stands out for its lock-in amplifier utilising in-phase (I) and quadrature (Q) demodulation signals to derive real and imaginary impedance components. Typically, the current injected into the tissue is controlled by a voltage-controlled current source (VCCS). However, the VCCS can introduce phase shifts leading to discrepancies in real/imaginary outputs, especially at the highest end of the operating frequency bandwidth. Such discrepancies can significantly impact diagnostic accuracy in applications reliant on precise tissue phase profiling, such as cancer and neuromuscular evaluations. In the present work, we propose an automatic phase error compensation stage for bioimpedance measurement systems to minimise this systematic error. Our experimental findings demonstrated a considerable reduction in phase error, with the Phase Error Compensated Synchronous Detection (PECSD) system exhibiting a maximum phase error of 2° (≤5% error) compared with the uncompensated SD system where error exceeded 20%. The improvements made by our proposed SD system hold great potential for enhancing the accuracy of impedance measurements, particularly in clinical diagnosis and disease detection. [ABSTRACT FROM AUTHOR]

Exposure to high altitude might cause the body to adapt with negative energy and fluid balance that compromise body composition and physical performance. In this field study involving 12 healthy adults, sex-balanced, and aged 29 ± 4 years with a body mass index of 21.6 ± 1.8 kg/m2, we investigated the effects of a 4-day trekking up to 4556 m a.s.l. on Monte Rosa (Alps, Italy). The food intake was recorded using food diaries and nutrient averages were calculated. The bio-impedance analysis was performed at low and high altitudes, and a wearable biosensor (Swemax) was used to track hydro-saline losses in two participants. Daily total energy intake was 3348 ± 386 kcal for males and 2804 ± 415 kcal for females (13%–14% protein, 35% fat, 44%–46% carbohydrates). Although there was a significant body weight loss (65.0 ± 9.3 vs. 64.2 ± 9.10 kg, p < 0.001, d = 1.398), no significant changes in body composition parameter were found but a trend in the increase of the bioelectrical phase angle in males (p = 0.059, d = −0.991). Body water percentage significantly changed (p = 0.026, η2p = 0.440), but the absolute water did not, suggesting that the weight loss was not due to water loss. Salivary and urinary osmolality did not change. A reduction in sweat rate at higher altitudes was observed in both participants. Interestingly, salivary leptin increased (p = 0.014, η2p = 0.510), and salivary ghrelin decreased (p = 0.036, η2p = 0.403). Therefore, the 4-day trekking at altitude of hypoxia exposure induced changes in satiety and appetite hormones. High altitude expeditions require more specific nutritional guidance, and using multiplex analysis could help in monitoring fluid balance and body composition. [ABSTRACT FROM AUTHOR]

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Objective: The search for other indicators to assess the weight status of individuals is important as it may provide more accurate information and assist in personalized medicine.This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy infant juvenile cohort from the Southern Cuba Region, Santiago de Cuba. Methods: The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 393 female and male infant and juvenile individuals are studied. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. A classification model are performed, followed by a prediction of other bioparameters influencing the weight status. Results: The results obtained from the classification model indicate that fat-free mass, reactance, and corrected resistance primarily influence the weight status of the studied population. Specifically, the regression model demonstrates that other bioparameters derived from impedance measurements can be highly accurate in estimating weight status. Conclusion: The classification and regression predictive models developed in this work are of the great importance for accessing to the weigh status with high accuracy of younger individuals at the Oncological Hospital in Santiago de Cuba, Cuba. [ABSTRACT FROM AUTHOR]

Introduction: The assessment of body composition through the analysis of Bioelectrical Impendance (BIA) has increased in clinical practice and hospital with on the parameter of the phase angle (PA) with application in the prognosis of the development of several diseases. Objective: To evaluate the application of the phase angle in the evolution of the treatment of overweight or obese individuals. Materials and Methods: Critical narrative review through bibliographic survey of scientific materials and articles on the application of the PA as a tool in cases involving overweight or obesity. Results: The PA is related to the integrity of the cell membrane may indicate the evolution and severity of a disease and cellular balance especially in individuals with an inflammatory profile who are at high risk of oxidative stress and cell damage. Factors such as ethnicity, sex and age interfere with the use of the PA as a monitoring tool of the evolution of overweight and obesity making its isolated application difficult for this case. The lack of studies for populations and the lack of standardization in obtaining data limit the use in clinical and hospital practice when related exclusively to monitoring the evolution of overweight and obesity. Conclusion: The PA has potential as an auxiliary tool in the prognosis of overweight and obese individuals. The lack of reference values for this public is an obstacle to its application in clinical and hospital practice requiring more specific studies by ethnicity, sex, and age groups. [ABSTRACT FROM AUTHOR]

Background The BioImpedance Spectroscopy to maintain Renal Output randomised controlled trial investigated the effect of bioimpedance spectroscopy added to a standardised fluid management protocol on the risk of anuria and preservation of residual kidney function (primary trial outcomes) in incident haemodialysis patients. Despite the economic burden of kidney disease, the cost-effectiveness of using bioimpedance measurements to guide fluid management in haemodialysis is not known. Objectives To assess the cost-effectiveness of bioimpedance-guided fluid management against current fluid management without bioimpedance. Design Within-trial economic evaluation (cost–utility analysis) carried out alongside the open-label, multicentre BioImpedance Spectroscopy to maintain Renal Output randomised controlled trial. Setting Thirty-four United Kingdom outpatient haemodialysis centres, both main and satellite units, and their associated inpatient hospitals. Participants Four hundred and thirty-nine adult haemodialysis patients with > 500 ml urine/day or residual glomerular filtration rate > 3 ml/minute/1.73 m2. Intervention The study intervention was the incorporation of bioimpedance technology-derived information about body composition into the clinical assessment of fluid status in patients with residual kidney function undergoing haemodialysis. Bioimpedance measurements were used in conjunction with usual clinical judgement to set a target weight that would avoid excessive fluid depletion at the end of a dialysis session. Main outcome measures The primary outcome measure of the BioImpedance Spectroscopy to maintain Renal Output economic evaluation was incremental cost per additional quality-adjusted life-year gained over 24 months following randomisation. In the main (base-case) analysis, this was calculated from the perspective of the National Health Service and Personal Social Services. Sensitivity analyses explored the impact of different scenarios, sources of resource use data and value sets. Results The bioimpedance-guided fluid management group was associated with £382 lower average cost per patient (95% CI −£3319 to £2556) and 0.043 more quality-adjusted life-years (95% CI −0.019 to 0.105) compared with the current fluid management group, with neither values being statistically significant. The probability of bioimpedance-guided fluid management being cost-effective was 76% and 83% at commonly cited willingness-to-pay threshold of £20,000 and £30,000 per quality-adjusted life-year gained, respectively. The results remained robust to a series of sensitivity analyses. Limitations The missing data level was high for some resource use categories collected through case report forms, due to COVID-19 disruptions and a significant dropout rate in the informing BioImpedance Spectroscopy to maintain Renal Output trial. Conclusions Compared with current fluid management, bioimpedance-guided fluid management produced a marginal reduction in costs and a small improvement in quality-adjusted life-years. Results from both the base-case and sensitivity analyses suggested that use of bioimpedance is likely to be cost-effective. Future work Future work exploring the association between primary outcomes and longer-term survival would be useful. Should an important link be established, and relevant evidence becomes available, it would be informative to determine whether and how this might affect longer-term costs and benefits associated with bioimpedance-guided fluid management. Funding details This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number HTA 14/216/01 (NIHR136142). Plain language summary ‘Bioimpedance’ is a measure of how difficult it is for an electric current to pass through a biological object. Bioimpedance is used in devices that assess fluid status (over- or under-hydration) because it is very sensitive to the amount of water in tissue. Bioimpedance can be used in addition to clinical judgement when deciding how much water should be removed from someone with kidney failure during a dialysis treatment session. This is the first study to examine whether using this treatment represents a cost-effective use of National Health Service resources. We carried out an economic evaluation within a large randomised controlled trial in patients with kidney disease undergoing haemodialysis. We calculated the additional costs and quality-adjusted life-years (a measure that combines quality and quantity of life) using established methods. Over 2 years, our study showed that taking into account bioimpedance measurements about target weight resulted in slightly lower costs and marginally more quality-adjusted life-years, although there is uncertainty around these findings.

IntroductionThe methods for diagnosing compartment syndrome non-invasively remain under debate. Bioimpedance measurements offer a promising avenue in clinical practice, detecting subtle changes in organ impedance due to volume shifts. This study explores bioimpedance measurement as a novel, painless method for diagnosing compartment syndrome, potentially enabling continuous monitoring.ObjectiveThis work aims to develop a prototype device for non-invasive diagnosis of compartment syndrome based on bioimpedance changes and assess initial results through in vitro experiments on inanimate biological material. We assume a change in the bioimpedance value after the application of physiological solution.Materials and MethodsBetween 2018 and 2022, a prototype device for diagnosing limb compartment syndrome was collaboratively developed with the Department of Cybernetics and Biomedical Engineering at the Technical University of Ostrava, Czech Republic. This device operates by comparing bioimpedance between two compartments, one of which is pathologically affected (experiencing compartment syndrome). The Bioimpedance Analyzer for Compartment Syndrome (BACS) has been utilized to conduct measurements on inanimate biological material in laboratory settings. Two samples of duck and chicken tissue, as well as piglets, were employed for these experiments. According to the size of sample was compartment syndrome simulated by injecting 20–120 mL saline into one limb (breast) while leaving the other as a control. Invasive intramuscular pressure measurements were conducted post-saline injection using a conventional device (Stryker). Changes in bioimpedance were evaluated following saline application.ResultsThe non-invasive bioimpedance measurement instrument has been developed. It meets the safety requirements of European standard EN 60601-1. Measurement of accuracy showed minimal deviation for both channels (1.08% for the left channel and 1.84% for the right channel) when measuring on resistors. Ten measurements were conducted using the BACS prototype - two on chicken legs, two on duck breasts, two on duck legs, and four on piglets. Compartment syndrome simulation was achieved for all 10 measurements (IMP variance 31–45 mmHg). Following saline application, a notable decrease in bioimpedance was observed in the compartment simulating compartment syndrome (decrease by 12–78 Ω).ConclusionNon-invasive methods could revolutionize limb compartment syndrome diagnosis, offering advantages such as non-invasiveness and continuous monitoring of compartment swelling.

IntroductionObesity in adults is a known risk factor for cardiovascular events and is associated with a decline in arterial elasticity. This study aims to evaluate the utility of pulse wave analysis (PWA) parameters in routine clinical practice for the primary prevention of cardiovascular events by developing a prediction model for arterial stiffness among obese and overweight individuals.MethodsThe study enrolled 84 adult patients, aged 18 to 85 years, with varying degrees of weight status, including optimal weight, overweight, and obesity. The lifestyle habits, the personal and family history of cardiometabolic diseases, as well the clinical evaluation that included BMI (body mass index), WHR (waist-to-hip ratio), WC (waist circumferance) were performed. PWA evaluation was conducted using the Mobil-O-Graph device, assessing the following parameters: pulse wave velocity (PWV), augmentation index (AIx), heart rate (HR), central pulse pressure (cPP), peripheral and central blood pressure (SBP, DBP, cSBP, cDBP). Body composition analysis was performed using the TANITA BC-418 body analyzer. Laboratory results from the past 3 months were also collected during initial nutritional consultations for each patient.ResultsFamily history of cardiovascular events showed positive correlations with all PWA parameters, while diabetes history only with PWV and family history of obesity with PWV, DBP, and cSBP. Insufficient sleep duration showed positive associations with all arterial stiffness parameters except cDBP. Smoking status correlated with significantly elevated PWV and Aix values, while insufficient physical activity was associated solely with PWV. Positive correlations were showed between current weight and PWV, while WC demonstrated positive associations with PWV, SBP, and cSBP. Body composition analysis revealed significant associations between trunk adipose tissue mass (%) and PWV, SBP, and cSBP. Hydration status (%) emerged as an independent predictor for PWV, exhibiting an inverse relationship. HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) showed a strong positive correlation with PWV. Negative associations were observed with HDL-c and vitamin D. Threshold values for age, cDBP and Cardiac Index providing positive diagnostic for vascular impairment.ConclusionThe assessment of arterial stiffness can be considered a reliable approach to prevent obesity-related cardiovascular events and facilitate the comprehensive management of such pathologies.

IntroductionMethods of body composition estimation such as dual-energy X-ray absorptiometry (DXA), anthropometry, and bioimpedance (BIA) are used for the estimation of skeletal muscle mass (SMM) and lean body mass (LBM). No previous studies have examined whether these methods generate comparable results, or whether they are valid by using DXA as the reference. The aims of the present investigation were: (a) to assess the differences between DXA, anthropometry, and BIA in the estimation of SMM and LBM, taking into consideration the impact of sex and hydration status; and (b) to examine the agreement of anthropometry and BIA as compared to DXA for the estimation of SMM and LBM.MethodsA descriptive cross-sectional design was followed with 262 healthy young adults (159 males and 103 females). LBM and SMM were assessed by anthropometry with the formulas from Lee et al. and Kulkarni et al. for LBM; and Kerr (opt a), Kerr (opt b), Lee et al., Poortmans, Matiegka, Martin et al., Drinkwater and Ross, and Heymsfield et al. for SMM; by BIA with the formula reported by the TANITA MC-780-MA software for LBM and SMM; and DXA with the formula reported by the Hologic Horizon software for LBM, and the conversion by Kim et al. for SMM.ResultsSignificant differences were found for both SMM and LBM in kg, and percentages between most methods and formulas for the overall sample (p