Journal of Electrical Bioimpedance最新文献

Intro: Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common procedures that improve mobility but carry a risk of postoperative complications, particularly in patients with obesity. Body Mass Index (BMI) is traditionally used for risk assessment but does not account for muscle mass or fat distribution. Bioelectrical impedance analysis (BIA) provides a more detailed body composition evaluation. This study investigates the association between BIA-derived metrics and postoperative complications in TKA and THA, hypothesizing that these metrics are superior predictors compared to BMI.

Methods: A retrospective cohort study was performed on 567 adult patients who underwent primary THA or TKA from January 2020 to December 2023. The data collected included demographic characteristics, comorbidities, preoperative laboratory values, preoperative BIA measurements and postoperative complications. Multivariate logistic regression models were developed to identify independent predictors of postoperative complications. Receiver operating characteristic (ROC) curves assessed the predictive accuracy of BIA-metrics models compared to BMI model.

Results: In a cohort of 567 patients (55.7% female, median age 66), no significant difference in BMI was found between the complication and non-complication groups. However, the complication group had a higher ECW/TBW ratio (0.396 vs. 0.393, p = 0.011), higher ECW/ICW ratio (0.657 vs. 0.647, p = 0.012), and a lower phase angle (4.65 vs. 4.80, p = 0.039). Multivariate logistic regression analysis revealed that higher standardized ECW/TBW (OR 1.65, 95% CI 1.17-2.31, p = 0.004) and ECW/ICW z-scores (OR 1.61, 95% CI 1.15-2.23, p = 0.005) were associated with increased odds of postoperative complications, while a lower phase angle was protective (OR 0.58, 95% CI 0.37-0.91, p = 0.018). ROC analysis showed moderate predictive accuracy for ECW/TBW (AUC 0.71, 95% CI 0.62-0.79), ECW/ICW (AUC 0.70, 95% CI 0.62-0.79), and phase angle (AUC 0.69, 95% CI 0.60-0.79). In contrast, BMI was not significantly associated with complications, and BMI model demonstrated inferior predictive accuracy (AUC 0.61).

Conclusion: ECW/TBW, ECW/ICW and phase angle are associated with postoperative complications in patients undergoing primary TKA or THA. These metrics provide better predictive accuracy than BMI enhancing preoperative risk stratification.

Electrodermal activity (EDA) is defined as a general term for all electrical behaviors in the skin, encompassing all active and passive electrical properties that can be traced back to the skin and its appendages. EDA measurements can be impacted by various factors and conditions. A factor of effect on EDA recordings, which has not been investigated before is the gender-related differences in the effects of skin hydration on EDA signals. Hence, this study aimed to study gender-related differences in the EDA parameters under conditions of skin hydration. 30 males and 30 females participated in this study under two different conditional (normal and hydration) experiments. Three EDA parameters (tonic and phasic components) were recorded from both groups. In the hydration experiment, 0.2 gram of 0.5% KCI in a 2% agar jelly was applied to the skin of all participants to moisturize their skin. The data from both experiments were analyzed to investigate gender-related differences in the effects of skin hydration on EDA measurements. It was found that EDA measurements, in particular the tonic component were not influenced by gender-related differences under hydration conditions. However, some significant (p<0.05) differences were observed between males and females in certain phasic parameters in response to specific stimuli. This study suggests that skin hydration does not contribute to gender-related differences in EDA recordings. These results are probably important in EDA investigations and applications.

In Vitro Fertilization (IVF) and Intracytoplasmic Sperm Injection (ICSI) are well-known fertility treatments that, due to resource-intensive, high degree of expertise required, and frequent subpar performances, often yield in high costs for treatment cycles. Microfluidic technology has enabled cost-effective egg-handling procedures towards new assistive reproductive devices: oocytes are subjected to microchannels with jagged surfaces to let shear stress remove undesirable cumulus cells, and microchannels with expansion units facilitate the transport of oocytes in chips. However, although the previous works have studied the influence of shear stress on oocyte denudation and the role of microchannel teeth in optimizing cell handling efficiency, the study of configurations of jagged surfaces and expansion units in microfluidic devices has remained elusive. Also, comprehensive analysis using both computational fluid dynamics (CFD) and real-world microfluidic devices has remained an unexplored area. To fill the abovementioned gap, this paper studies microfluidics chips with different expansion units to depict the behavior of oocytes when subjected to controlled input flows. The proposed chips were developed and fabricated using a direct engraving CO₂ laser machine on polymethyl methacrylate (PMMA) sheets and bonded in a natural ventilation lab oven, rendering the highly efficient and low-cost microfluidic chips for oocyte denudation. The effect of the expansion units has been investigated in CFD simulation and real lab experimentation with mature buffalo oocytes at a constant flow rate, and a chip with five expansion units arranged in two lines achieved 98.33% denudation efficiency, low-cost fabrication (about 1 USD), and quick fabrication time (about 20 minutes).

Electrical Impedance Tomography (EIT) is a non-invasive method for imaging conductivity distributions within a target area. The inverse problem associated with EIT is nonlinear and ill-posed, leading to low spatial resolution reconstructions. Iterative algorithms are widely employed to address complex inverse problems. However, current iterative methods have notable limitations, such as the arbitrary and subjective selection of initial parameters, lengthy computational times due to numerous iterations, and the generation of reconstructions that suffer from shape blurring and a lack of higher-order detail. To address these issues, this study investigates the impact of using ISTA and FISTA iterative algorithms on the image reconstruction process in EIT. It focuses on enhancing the convergence and accuracy of EIT image reconstruction by evaluating the effectiveness of these optimization algorithms when applied to regularized inverse problems, using standard regularization techniques. ISTA and FISTA were compared to the NOSER and Newton-Raphson methods and validated through simulation and experimental results. The results show that ISTA and FISTA achieve better visualization and faster convergence than conventional methods in terms of computational efficiency when solving regularized problems, achieving conductivity reconstructions with an accuracy of above 80%. The paper concludes that while ISTA and FISTA significantly enhance EIT image reconstruction performance, the quality of the reconstructed images heavily depends on the choice of regularization methods and parameters, which are crucial to the reconstruction process.

The Focused Impedance method (FIM), an innovation by Dhaka University, Bangladesh, is a new technique for focusing a region of interest of a volume conductor through a simple enhancement of the age-old Tetra-Polar Impedance Method (TPIM). This innovation has potential in the diagnosis of different kinds of physiological disorders. This paper presents the study of lung ventilation on different human subjects using the six-electrode version of the Focused Impedance Method (FIM-6) with the circuit indigenously designed in Nepal. The study was carried out for different quadrants of the lungs of three normal male subjects using both TPIM and FIM-6 configurations, measuring the percentage change in transfer impedance between full inspiration and full expiration. The percentage changes observed were in the range of 15% to 27%. However, errors are expected due to movement of the heart and other organs between inspiration and expiration, which may be difficult to eliminate.

Wearable and portable devices are gaining significant popularity across consumer electronics as well as in medical and industrial fields. To ensure that these devices are both comfortable and appealing to users, they need to have low battery consumption and be compact in both size and weight. The EGluco project is focused on developing a wearable device for non-invasive blood glucose monitoring. This multi-sensor device incorporates electrical bioimpedance spectroscopy as one of its measurement techniques. One of the earlier versions of the device was deemed unsuitable as a wearable due to its large size and high power consumption. To make the device more suitable for wearability, the previous hardware was assessed, and a new design was proposed that simplified the system's power supply and reduced the operating voltage. This article presents two of these designs: an improved Howland current source with a supply voltage of 3.3 V, an output current of 250 μA, and the ability to conduct bioimpedance analysis up to 1 MHz using pulsed DIBS (Discrete Interval Binary Sequence) signals, and an instrumentation amplifier with the same supply voltage as the current source, a voltage gain of four, and a slew rate of 150 V/μs. By simplifying the power supply and implementing other changes, the device's size was reduced to a single 5 × 5 cm circuit board, compared to the previous configuration of four separate boards connected by cables.

The conductive polymeric electrodes using 3D printing are an innovative material development with the advantage of the flexibility of integrating isolated polymers with a higher electrical conductivity of carbon-based materials, generating new possibilities in environmental, healthcare, and food monitoring. Based on the morphology, geometric arrangement, and dielectric properties of the composites, the performance of the electrodes is improved. Structural designs are optimized to enhance functionalities such as adhesion, catalytic activity, and the reduction of interface energy. With these concepts, a functionalized carbon-based polymeric electrode was fabricated using 3D printing. The Differential Impedance Spectrum (DIS) was employed to analyze the response of functionalized electrodes to solutions of acetic acid and calcium chloride (CaCl₂ ). DIS data extract the differential phase angle and indicate the interactions between the functionalized surface with acetic acid and CaCl₂ solutions, showing noticeable peaks in three zones: at lower frequencies (< 10 kHz), medium frequencies range of 10 kHz to 100 kHz, and higher frequencies (> 100 kHz). In the three cases analyzed, the CaCl₂ solution presented the highest frequency compared with acetic acid. When the sensor was doubled functionalized, the peaks were shifted between the range of 220 kHz to 280 kHz. A conclusion is that the carbon-based polymer electrode not only reduces manufacturing costs but also enables faster functionalization to detect specific chemical compounds in liquids quickly and portable without the need for higher-level equipment. These electrodes could be applied to make measurements in aqueous media such as ponds, pools, lakes, rivers, and oceans to detect contaminants, as well as in human fluids to recognize metabolites in sweat, urine, saliva, and blood.

Electrical bioimpedance is based on the opposition exerted by body tissues to the passage of an electrical current. This characteristic allows the assessment of the individual's body composition, nutritional status, and hydration status. Electrical bioimpedance can be used to estimate body composition, health-related markers, general health status, diagnosis and prognostic of diseases, evaluation of treatment progress, and others. The aim of this study is to propose a methodology that allows us to integrate two methods of electrical bioimpedance analysis: bioelectrical impedance vector analysis, and bioelectrical impedance spectroscopy to evaluate the health of individuals. For methodology validation a retrospective clinical investigation was carried out where the data of healthy individuals and cancer patients included in the Database of the characterization of bioelectrical parameters by electrical Bioimpedance methods were analyzed. The values of electrical resistance and electrical reactance are higher in cancer patients compared to healthy individuals. However, the phase angle is lower in these patients. In the advanced stages of the disease, patients are located outside the tolerance ellipses. All these results are obtained at the characteristic frequency. The integration of bioelectrical impedance vector analysis, and bioelectrical impedance spectroscopy can be a sensitive complementary tool, capable of establishing differences between healthy individuals and cancer patients. Enrichment could be achieved by including the analysis of different physiological parameters through estimation equations validated by BIS parameters.

The current stage of development of medical science is characterized by growing interest in constitutional typology and clinical anthropology. The anatomical-anthropological approach is an integrative technique of biology and medicine that allows us to determine the criteria for normality and pathology of a person. Purpose of the study: comparative bioimpedance assessment of somatic types of body component composition among the first mature age period people residing in highland. Study design: a comparative bioimpedance assessment of body types according to the Heath and Carter's scheme was performed to identify somatic types and body weight composition in healthy men of the 1^st adulthood period living in high mountains (2469-3325 m above sea level). Somatotypical features of body composition have been established. An intertype and correlation analysis of body composition was conducted in individuals with different body types. Results: comparative bioimpedance and correlation analyses revealed differences in body composition indicators depending on population, age, body types and living conditions. Conclusion: mesoectomorphy, balanced ectomorphic, central and meso-endo types prevailed among the somatotype subgroups.