Non-invasive blood pressure as an application of electrical impedance: a short review

Abstract Electrical bioimpedance (EBI) has gained importance as a diagnostic technique in medicine to determine the electrical properties of tissues. For example, it has been used in tissue characterization, cancer detection, and electromyography. Some of the characteristics of EBI are its low cost, the absence of irradiation during the measurement process, and its non-invasive nature. In this sense, there is interest in developing medical equipment that performs non-invasive measurements of blood pressure (BP). Electrical Impedance Plethysmography (EIP) is a technique commonly used to extract the waveform associated with BP. In this short review, we will cover research articles published in peer-reviewed journals during the last decades, and show developments in the area of EIP, with a brief discussion of relevant results and current challenges.

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In vivo electrical impedance measurement in human skin assessment

Pure and Applied Chemistry ◽

10.1515/pac-2018-1106 ◽

2019 ◽

Vol 91 (9) ◽

pp. 1481-1491 ◽

Cited By ~ 1

Author(s):

Leszek Kubisz ◽

Dorota Hojan-Jezierska ◽

Maria Szewczyk ◽

Anna Majewska ◽

Weronika Kawałkiewicz ◽

...

Keyword(s):

Human Skin ◽

Electrical Impedance ◽

Clinical Status ◽

Impedance Measurement ◽

Short Review ◽

Non Invasive ◽

Fish Collagen ◽

Electrical Impedance Measurement ◽

The One

Abstract Structural and chemical alterations in living tissue are reflected in electrical impedance changes. However, due to the complexity of skin structure, the relation between electrical parameters and physiological/pathological conditions is difficult to establish. The impedance dispersion reflects the clinical status of the examined skin tissue and, therefore, it is frequently used in a non-invasive evaluation of exposing skin to various factors. The method has been used to assess the effect of the fish collagen on the skin of patients suffering from the leg ulcer. Therefore, from a number of different approaches to skin electrical impedance dispersion, the one considered to be safe was selected and applied. This paper presents a short review of different technical approaches to in vivo electrical impedance measurements, as well as an analysis of the results and the effect of fish collagen locally administered on human skin.

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Development a low-cost electrical impedance tomography system for non-invasively detecting abnormal in breast tissue - Phantom study-

10.29007/x6vj ◽

2022 ◽

Author(s):

Minh Quan Cao Dinh ◽

Quoc Tuan Nguyen Diep ◽

Hoang Nhut Huynh ◽

Ngoc An Dang Nguyen ◽

Anh Tu Tran ◽

...

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Low Cost ◽

Impedance Tomography ◽

Non Invasive ◽

Tomography System ◽

Tissue Phantom ◽

Cost System ◽

Invasive Method ◽

Breast Tissues

Electrical Impedance Tomography (EIT) is known as non-invasive method to detect and classify the abnormal breast tissues. Reimaging conductivity distribution within an area of the subject reveal abnormal tissues inside that area. In this work, we have created a very low-cost system with a simple 16-electrode phantom for doing research purposes. The EIT data were measured and reconstructed with EIDORS software.

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A novel device for non-invasive cerebral perfusion assessment

Veins and Lymphatics ◽

10.4081/vl.2015.4650 ◽

2015 ◽

Vol 4 (1) ◽

Author(s):

Mirko Tessari ◽

Anna Maria Malagoni ◽

Maria Elena Vannini ◽

Paolo Zamboni

Keyword(s):

Near Infrared ◽

Single Photon ◽

Human Subjects ◽

Low Cost ◽

Photon Emission ◽

Diagnostic Technique ◽

Brain Perfusion ◽

Emission Computed Tomography ◽

Wide Field ◽

Non Invasive

Currently brain perfusion can be assessed by the means of radio-invasive methods, such as single-photon emission computed tomography and positron emission tomography, or by hightech methods such as magnetic resonance imaging. These methods are known to be very expensive, with long examination time, and finally, cannot be used for assessing brain oxygen distribution in relation to exercise and/or cognition-tests. The near infrared spectroscopy (NIRS) is a non-invasive diagnostic technique. In real time it is capable of measuring tissue oxygenation using portable instrumentation with a relative low cost. We and other groups previously adopted this instrument for investigation of the oxygen consumption in the muscles at rest and during exercise. NIRS can be now used to assess brain perfusion through the intact skull in human subjects by detecting changes in blood hemoglobin concentrations. Changes in perfusion can be related to both arterial and venous problems. This novel equipment features allow for a wide field of innovative applications where portability, wearability, and a small footprint are essential. The present review shows how to use it in relation to exercise protocols of the upper and lower extremities, measured in healthy people and in conditions of arterial and chronic cerebro-spinal venous insufficiency.

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A LabVIEW-based electrical bioimpedance spectroscopic data interpreter (LEBISDI) for biological tissue impedance analysis and equivalent circuit modelling

Journal of Electrical Bioimpedance ◽

10.5617/jeb.2978 ◽

2019 ◽

Vol 7 (1) ◽

pp. 35-54 ◽

Cited By ~ 10

Author(s):

Tushar Kanti Bera ◽

Nagaraju Jampana ◽

Gilles Lubineau

Keyword(s):

Electrical Impedance ◽

Tissue Characterization ◽

Impedance Analysis ◽

Biological Tissues ◽

Impedance Spectra ◽

Circuit Element ◽

Tissue Impedance ◽

Wide Range ◽

Electrical Bioimpedance ◽

Impedance Parameters

Abstract Under an alternating electrical signal, biological tissues produce a complex electrical bioimpedance that is a function of tissue composition and applied signal frequencies. By studying the bioimpedance spectra of biological tissues over a wide range of frequencies, we can noninvasively probe the physiological properties of these tissues to detect possible pathological conditions. Electrical impedance spectroscopy (EIS) can provide the spectra that are needed to calculate impedance parameters within a wide range of frequencies. Before impedance parameters can be calculated and tissue information extracted, impedance spectra should be processed and analyzed by a dedicated software program. National Instruments (NI) Inc. offers LabVIEW, a fast, portable, robust, user-friendly platform for designing data-analyzing software. We developed a LabVIEW-based electrical bioimpedance spectroscopic data interpreter (LEBISDI) to analyze the electrical impedance spectra for tissue characterization in medical, biomedical and biological applications. Here, we test, calibrate and evaluate the performance of LEBISDI on the impedance data obtained from simulation studies as well as the practical EIS experimentations conducted on electronic circuit element combinations and the biological tissue samples. We analyze the Nyquist plots obtained from the EIS measurements and compare the equivalent circuit parameters calculated by LEBISDI with the corresponding original circuit parameters to assess the accuracy of the program developed. Calibration studies show that LEBISDI not only interpreted the simulated and circuit-element data accurately, but also successfully interpreted tissues impedance data and estimated the capacitive and resistive components produced by the compositions biological cells. Finally, LEBISDI efficiently calculated and analyzed variation in bioimpedance parameters of different tissue compositions, health and temperatures. LEBISDI can also be used for human tissue impedance analysis for electrical impedance-based tissue characterization, health analysis and disease diagnosis.

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Development and evaluation of a low cost 8-electrode Electrical Impedance Tomography system

Journal of Physics Conference Series ◽

10.1088/1742-6596/2008/1/012002 ◽

2021 ◽

Vol 2008 (1) ◽

pp. 012002

Author(s):

C E Castillo ◽

A E Álvarez

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Imaging Modality ◽

Low Cost ◽

Region Of Interest ◽

Electrical Current ◽

Maximum Error ◽

Impedance Tomography ◽

Homogeneous Test ◽

Electrical Properties Of Tissues

Abstract Electrical impedance tomography (EIT) is a medical imaging modality that considers the electrical properties of tissues to obtain a conductivity distribution of a region of interest using the level of resistance it presents to the passage of a small electrical current. This work describes the design of an 8-electrode EIT prototype that offers the possibility of changing the excitation parameters and freedom of movement of the demodulation synchrony by means of conventional electronics. The image reconstruction obtained can locate disturbances in the study medium using the adjacent electrode method. A comparison of the voltage measurements acquired on a homogeneous test medium in two different collection cycles was implemented to determine the precision of the system. The data obtained indicate a maximum error percentage of 2.6% between measurements, which represents an acceptable first approach towards the design of a device with greater stability and precision.

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Low-cost oscillometric non-invasive blood pressure monitors: device repeatability and device differences

Physiological Measurement ◽

10.1088/0967-3334/26/4/010 ◽

2005 ◽

Vol 26 (4) ◽

pp. 441-445 ◽

Cited By ~ 9

Author(s):

A J Sims ◽

C A Reay ◽

D R Bousfield ◽

J A Menes ◽

A Murray

Keyword(s):

Blood Pressure ◽

Low Cost ◽

Invasive Blood Pressure ◽

Non Invasive ◽

Blood Pressure Monitors

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Wearable Piezoelectric-Based System for Continuous Beat-to-Beat Blood Pressure Measurement

Sensors ◽

10.3390/s20030851 ◽

2020 ◽

Vol 20 (3) ◽

pp. 851 ◽

Cited By ~ 6

Author(s):

Ting-Wei Wang ◽

Shien-Fong Lin

Keyword(s):

Blood Pressure ◽

Pressure Measurement ◽

Blood Pressure Monitoring ◽

Low Cost ◽

Blood Pressure Measurement ◽

Pressure Change ◽

Absolute Error ◽

Non Invasive ◽

Blood Pressure Estimation

Non-invasive continuous blood pressure measurement is an emerging issue that potentially can be applied to cardiovascular disease monitoring and prediction. Recently, many groups have proposed the pulse transition time (PTT) method to estimate blood pressure for long-term monitoring. However, the PTT-based methods for blood pressure estimation are limited by non-specific estimation models and require multiple calibrations. This study aims to develop a low-cost wearable piezoelectric-based system for continuous beat-to-beat blood pressure measurement. The pressure change in the radial artery was extracted by systolic and diastolic feature points in pressure pulse wave (PPW) and the pressure sensitivity of the sensor. The proposed system showed a reliable accuracy of systolic blood pressure (SBP) (mean absolute error (MAE) ± standard deviation (SD) 1.52 ± 0.30 mmHg) and diastolic blood pressure (DBP, MAE ± SD 1.83 ± 0.50), and its performance agreed with standard criteria of MAE within 5 mmHg and SD within ±8 mmHg. In conclusion, this study successfully developed a low-cost, high-accuracy piezoelectric-based system for continuous beat-to-beat SBP and DBP measurement without multiple calibrations and complex regression analysis. The system is potentially suitable for continuous, long-term blood pressure-monitoring applications.

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Tomography for electrical impedance

Ingeniería solidaria ◽

10.16925/2357-6014.2020.01.05 ◽

2020 ◽

Vol 16 (1) ◽

Author(s):

Juan David Muñoz Sánchez ◽

Víctor Hugo Mosquera Leyton

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Wrist Joint ◽

Low Cost ◽

Good Alternative ◽

Medical Applications ◽

Joint Diseases ◽

Impedance Tomography ◽

Non Invasive ◽

Joint Injuries

Introduction:This review article shows the state of the art of different techniques for monitoring joint injuries. This work is the product of the research project "Viability of electrical impedance tomography for the monitoring of joint injuries", which took place at the University of Cauca during the period 2018-2019. Aim:Identify non-invasive bio-image methods that are used in the evaluation of joint diseases. Methodology: Selection and review of papers related to the evaluation of joint injuries using non-invasive bio-image technologies using systematic mapping. Results: Magnetic resonance and computed tomography systems make up the non-invasive methods of greater reliability and application in the evaluation of joint injuries. Similarly, some studies show good results from other methods such as systems based on bio-impedance when monitoring the deterioration of joint cartilage. However, electrical impedance tomography (EIT) devices have not yet been widely studied in the joint injuries evaluation. Conclusion: Electronic prototypes of low-cost electrical impedance tomography have been developed that have allowed for the detection and recognition of gestures made by hand from the analysis of the distribution of conductivity in the wrist joint, which allows us to infer that EIT could be a good alternative for the monitoring of joint injuries. Originality: The literature does not show studies focused on the development and implementation of EIT systems in medical applications related to joint injuries. Limitations: This review paper only mentions those studies that describe the non-invasive bio-image methods used to evaluate joint diseases, including the medical applications of EIT systems.

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Left ventricular myocardial work in patients with high gradient severe symptomatic aortic stenosis

European Heart Journal ◽

10.1093/eurheartj/ehab724.1553 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

Author(s):

G Sa Mendes ◽

J Abecasis ◽

S Maltez ◽

S Guerreiro ◽

P Freitas ◽

...

Keyword(s):

Blood Pressure ◽

Aortic Stenosis ◽

Ejection Fraction ◽

Tissue Characterization ◽

Left Ventricular ◽

Low Flow ◽

Lv Function ◽

High Gradient ◽

Non Invasive ◽

Lv Ejection Fraction

Abstract Background Left ventricular myocardial work (LVMW) is a novel method to evaluated left ventricular (LV) function using pressure-strain loops. It might correct global longitudinal strain (GLS) for afterload, being eventually useful to assess whether GLS reduction is due to reduced contractility (reflected as reduced myocardial work) or increased afterload (reflected as increased myocardial work). Aim To describe indices of LVMW in a group of patients with severe symptomatic aortic stenosis (AS). Methods We prospectively studied 104 consecutive patients (age: 71 years [IQR 66.5–75.5] years, 51% men) with severe symptomatic high gradient AS: mean transaortic pressure gradient: 56.5mmHg [IQR 46.8–67.8]; aortic valve area: 0.73cm2 [IQR 0.61–0.88]; indexed stroke volume: 47.7±1.3 mL/m2 (11 patients with low-flow AS), preserved LV ejection fraction (EV) (LVEF: 56.0% [51.0–61.3]; GLS: −14.5% [IQR −16.1 to −10.6]), with no previous coronary artery disease and no history of cardiomyopathy. Beyond complete transthoracic echocardiography, all patients underwent cardiac magnetic resonance for LV myocardium tissue characterization. As proposed for AS, LV systolic pressure was corrected adding the mean transaortic pressure gradient to non-invasive systolic blood pressure cuff measurement in the echocardiographic algorithm. Four LVMW indices were collected in 83 patients (patients excluded for atrial fibrillation, left bundle branch block or absence of non-invasive blood pressure registration) and correlated to LV function indexes, LV hypertrophy and remodeling, myocardial tissue characterization, BNP and troponin levels (Pearson or Spearman correlation). These same indexes were compared in patients with LV ejection fraction (EF) below and above 50%, normal and reduced flow and presence of replacement fibrosis. Results Global constructive work (GCW) (2658.6±76.4mmHg%), global myocardial work (GMW) (2218.7±74.9mmHg%) and global wasted work (GWE) (262.0mmHg% [198.8–339.5]) were high above normal with concomitant lower work efficiency (WE) (88.0% [83.2–91.8]. Weak correlations were found between LVMW indexes and parameters describing aortic valve severity, flow and LV function (table). Except for significant differences of LVMI in patients with reduced LV ejection fraction (GCW 2770.3±687.4 vs 2056.0±380.7mmHg%, p=0,014 and GMW 2362.5±657.9 vs 1621.3±319.9, p=0,021 in patients with LV EF>50% vs. LV EF<50%, respectively) work indexes were neither significantly different in low-flow patients nor in those with myocardial late gadolinium enhancement. Conclusions Global constructive and myocardial work are increased in these patients with severe aortic stenosis. This might reflect an increased afterload predominance rather than a LV functional impairment, particularly relevant in this group of patients with exclusive high gradient disease and preserved LVEF. FUNDunding Acknowledgement Type of funding sources: None. Correlations between LVMI – LV function

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Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review

Journal of Medical Engineering ◽

10.1155/2014/381251 ◽

2014 ◽

Vol 2014 ◽

pp. 1-28 ◽

Cited By ~ 99

Author(s):

Tushar Kanti Bera

Keyword(s):

Electrical Impedance ◽

Tissue Characterization ◽

Bioelectrical Impedance ◽

Impedance Analysis ◽

Biological Tissues ◽

Disease Diagnosis ◽

Impedance Plethysmography ◽

Electrical Impedance Spectroscopy ◽

Signal Frequency ◽

Impedance Tomography

Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends.

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