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Open access

Leslie D. Montgomery, Richard W. Montgomery, Wayne A. Gerth, Michael Bodo, Julian M. Stewart and Marty Loughry

Abstract

This paper describes a new combined impedance plethysmographic (IPG) and electrical bioimpedance spectroscopic (BIS) instrument and software that will allow noninvasive real-time measurement of segmental blood flow, intracellular, interstitial, and intravascular volume changes during various fluid management procedures. The impedance device can be operated either as a fixed frequency IPG for the quantification of segmental blood flow and hemodynamics or as a multi-frequency BIS for the recording of intracellular and extracellular resistances at 40 discrete input frequencies. The extracellular volume is then deconvoluted to obtain its intravascular and interstitial component volumes as functions of elapsed time. The purpose of this paper is to describe this instrumentation and to demonstrate the information that can be obtained by using it to monitor segmental compartment volume responses of a pig model during simulated hemorrhage and resuscitation. Such information may prove valuable in the diagnosis and management of rapid changes in the body fluid balance and various clinical treatments.

Open access

Mohammad Karimi Moridani, Fatemeh Choopani and Mandana Kia

Abstract

The purpose of this paper is to identify differences between abnormal and normal lung signals gathered by an EIT device, which is a new, non-invasive system that seeks the electrical conductivity and permittivity inside a body. Lung performances in patients are investigated using Phase Space Mapping technique on Electrical EIT signals. The database used in this paper contains 82 registered records of 52 individuals with proper lung volume. The results of this paper show that as the delay parameter (τ) increases, the SD1 parameter of phase space mapping indicates a significant difference between normal and abnormal lung volumes. The value of the SD1 parameter with τ = 6 in the case that the lung volume is in a normal condition is 342.57 ± 32.75 while it is 156.71 ± 26.01 in non-optimal mode. This method can be used to identify the patients’ lung volumes with chronic respiratory illnesses and is an accurate assessment of the diverse methods to treat respiratory system illnesses in addition to saving various therapeutic costs and dangerous consequences that are likely to occur by using improper treatment methods. It can also reduce the required treatment durations.

Open access

Abdul Hamid Ismail, Georg Schlieper, Marian Walter, Jürgen Floege and Steffen Leonhardt

Abstract

The feasibility of bioimpedance spectroscopy (BIS) techniques for monitoring intradialytic changes in body fluids is advancing. The aim of this study was to compare the knee-to-knee (kkBIS) with the traditional whole-body (whBIS) with respect to continuous assessment of fluid volume status in hemodialysis patients. Twenty patients divided into two groups, hemodynamically stable and unstable, were recruited. Bioimpedance data from two different electrodes configurations (hand-to-foot and knee-to-knee) were collected and retrospectively analysed. A good correlation between the two methods with respect to changes in extracellular resistance (Re) and Re normalized for ultrafiltration volume (ΔRe/UFV) with p < 0.001 was observed. The relationship between relative change (%) in ΔRe and that in patient weight was most notable with kkBIS (4.82 ± 3.31 %/kg) in comparison to whBIS (3.69 ± 2.90 %/kg) in unstable patients. Furthermore, results based on kkBIS showed a reduced ability of the thigh compartments to keep up with the volume changes in the trunk for unstable patients. kkBIS provided a comparable sensitivity to whBIS even in patients at risk of intradialytic hypotension while avoiding the need for the complex implementation imposed by whBIS or other configurations.

Open access

Abdullah Jafari Chashmi and Mehdi Chehel Amirani

Abstract

Primary recognition of heart diseases by exploiting computer aided diagnosis (CAD) machines, decreases the vast rate of fatality among cardiac patients. Recognition of heart abnormalities is a staggering task because the low changes in ECG signals may not be exactly specified with eyesight. In this paper, an efficient approach for ECG arrhythmia diagnosis is proposed based on a combination of discrete wavelet transform and higher order statistics feature extraction and entropy based feature selection methods. Using the neural network and support vector machine, five classes of heartbeat categories are classified. Applying the neural network and support vector machine method, our proposed system is able to classify the arrhythmia classes with high accuracy (99.83%) and (99.03%), respectively. The advantage of the presented procedure has been experimentally demonstrated compared to the other recently presented methods in terms of accuracy.

Open access

David Cheneler, James Bowen and Georgia Kaklamani

Abstract

Mechanotransduction is of fundamental importance in cell physiology, facilitating sensing in touch and hearing as well as tissue development and wound healing. This study used an impedance sensor to monitor the effective resistance and permittivity of artificial tissues, alginate hydrogel with encapsulated fibroblasts, which were kept viable through the use of a bespoke microfluidic system. The observed transient impedance responses upon the application of identical compressive normal loads differed between acellular hydrogels and hydrogels in which fibroblasts were encapsulated. These differences resulted from changes in the conductivity and permeability of the hydrogel due to the presence of the encapsulated fibroblasts, and transient changes in ion concentrations due to mechanotransduction effects.

Open access

Leslie D. Montgomery, Richard W. Montgomery, Wayne A. Gerth, Marty Loughry, Susie Q. Lew and Manuel T. Velasquez

Abstract

This paper describes a new combined impedance plethysmographic (IPG) and electrical bioimpedance spectroscopic (BIS) instrument and software that allows noninvasive real-time measurement of segmental blood flow and changes in intracellular, interstitial, and intravascular volumes during various fluid management procedures. The impedance device can be operated either as a fixed frequency IPG for the quantification of segmental blood flow and hemodynamics or as a multi-frequency BIS for the recording of intracellular and extracellular resistances at 40 discrete input frequencies. The extracellular volume is then deconvoluted to obtain its intra-vascular and interstitial component volumes as functions of elapsed time. The purpose of this paper is to describe this instrumentation and to demonstrate the information that can be obtained by using it to monitor segmental compartment volumes and circulatory responses of end stage renal disease patients during acute hemodialysis. Such information may prove valuable in the diagnosis and management of rapid changes in the body fluid balance and various clinical treatments.

Open access

Christian Tronstad and Are H. Pripp

Abstract

This paper gives a basic overview of relevant statistical methods for the analysis of bioimpedance measurements, with an aim to answer questions such as: How do I begin with planning an experiment? How many measurements do I need to take? How do I deal with large amounts of frequency sweep data? Which statistical test should I use, and how do I validate my results? Beginning with the hypothesis and the research design, the methodological framework for making inferences based on measurements and statistical analysis is explained. This is followed by a brief discussion on correlated measurements and data reduction before an overview is given of statistical methods for comparison of groups, factor analysis, association, regression and prediction, explained in the context of bioimpedance research. The last chapter is dedicated to the validation of a new method by different measures of performance. A flowchart is presented for selection of statistical method, and a table is given for an overview of the most important terms of performance when evaluating new measurement technology.

Open access

Venkatratnam Chitturi and Nagi Farrukh

Abstract

Electrical impedance tomography (EIT) is a relatively new imaging technique. It has the advantages of low cost, portability, non-invasiveness and is free from radiation effects. So far, this imaging technique has shown satisfactory results in functional imaging. However, it is not yet fully suitable for anatomical imaging due to its poor spatial resolution. In this paper, we review the basic directions of research in the area of the spatial resolution of the EIT systems. The improvements to the hardware and the software developments are highlighted. Finally, possible techniques to enhance the spatial resolution of the EIT systems using array processing beamforming methods are discussed.

Open access

Ørjan G.Martinsen, Oliver Pabst, Christian Tronstad and Sverre Grimnes

Abstract

Alternating current methods have the potential to improve the measurement of electrodermal activity. However, there are pitfalls that should be avoided in order to perform these measurements in a correct manner. In this paper, we address issues like the choice of measurement frequency, placement of electrodes and the kind of electrodes used. Ignoring these factors may result in loss of measurement sensitivity or erroneous measurements with artifacts that contain little or no physiological information.

Open access

John G. Webster