Measuring Breathing Pattern in Patients With Chronic Obstructive Pulmonary Disease by Electrical Impedance Tomography

Balleza, Marco; Calaf, Núria; Feixas, Teresa; González, Mercedes; Antón, Daniel; Riu, Pere J.; Casán, Pere

doi:10.1016/s1579-2129(09)72431-0

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…The analysis of the changes in relative impedance in a given area of interest particular (ROI) can be used to calculate the amplitude of the change in bioimpedance (tidal volume), 16,17 the minimum impedance (functional residual capacity) 18 or the maximum impedance (total lung capacity). 19 Such an analysis has also been used to observe the distribution of gas volume in the lung, varying the parameters of the ventilator.…”

Section: Monitorization Of Alveolar Ventilationmentioning

confidence: 99%

Electrical impedance tomography in acute lung injury

Riera

Riu

Casán

et al. 2011

Medicina Intensiva (English Edition)

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Section: Monitorization Of Alveolar Ventilationmentioning

confidence: 99%

Electrical impedance tomography in acute lung injury

Riera

Riu

Casán

et al. 2011

Medicina Intensiva (English Edition)

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“…This is performed via injecting electrical current successively from two electrodes and reading the induced voltages on the remaining electrodes placed on the surface [1][2][3]. EIT has attracted much interest in medicine [4][5][6], as well as industry [7][8][9][10] because of its high speed and safety. The recovery of conductivity distribution from surface data is in principle to calculate the coefficient of an elliptical partial differential equation subject to a mixed Dirichlet/Neumann boundary condition [11].…”

Section: Introductionmentioning

confidence: 99%

An accelerated version of alternating direction method of multipliers for TV minimization in EIT

Javaherian

Soleimani

Möeller

et al. 2016

Applied Mathematical Modelling

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Existing total variation (TV) solvers that have been applied in Electrical Impedance Tomography (EIT) smooth the TV function in order to cope with its nondifferentiability around the origin, and thus imposes some numerical errors on the solution. Furthermore, these solvers require storage of Hessian, and are thus very impractical for large-scale computations, especially 3D EIT. These shortcomings were addressed by TV solvers that are based on first-order optimization methods. However, the application of these solvers to EIT remains scarce. In this manuscript, we proposes an accelerated version of a gradient-based TV solver based on Augmented Lagrangian and alternating direction method of multipliers, referred to as TVAL3, and apply it to EIT. The results demonstrate the superiority of the accelerated algorithm over existing TV solvers in EIT with regard to both accuracy and speed.

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“…This phenomenon was evidenced in previous studies performed by our research group. In those, a set of calibration equations was obtained for being used by EIT device in a group of healthy volunteers [29] (females and males) and chronic obstructive pulmonary disease (COPD) patients [30]. From the obtained results, it was evidenced that the mathematical adjustment of calibration equation for male was better than that obtained for female.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies, all mathematical models were obtained by a multivariate linear regression of (1) the anthropometric parameters and (2) the proportionality coefficients defined by the impedance and volume signals [29]. In order to estimate the volume changes, based on the EIT impedance measurements, all the elements of EIT image were used [29,30]. Our main challenge is to find a mathematical model that allows to transform impedance changes from a ROI, into a measurable volume signal with the least possible error.…”

Section: Introductionmentioning

confidence: 99%

“…The ROIs are subareas selected from EIT image by three different methods that were designed for this study by our research group. All calibration equations were determined in the same way as in our previous works [29,30], using a multivariate linear regression to relate the anthropometric parameters and the coefficients of proportionality estimated by the quotient of impedance (from ROI's) and volume (from pneumotachometer) determinations. Afterward, the resulted calibration equations were assessed in independent groups of volunteers (validation groups).…”

Section: Introductionmentioning

confidence: 99%

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Tidal volume monitoring by electrical impedance tomography (EIT) using different regions of interest (ROI): Calibration equations

Balleza

Alday

Vargas-Luna

et al. 2015

Biomedical Signal Processing and Control

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a b s t r a c t A set of calibration equations was previously obtained to transform the lung impedance changes obtained by electrical impedance tomography (EIT), using all frame's elements, into a measurable volume signal. In order to study the goodness of the use of regions of interest (ROI) for lung ventilation monitoring, we considered 6 different ROI to obtain a calibration equation for each area. Our aim was to compare the results, determined by these areas, and those obtained by using all EIT image elements. Two ROI's were defined by those pixels with an impedance change higher than 30% and 70% of the maximum change value. These areas were called P30 and P70, respectively. Two other ROI were defined by bounding two areas by mouse, resembling P30 and P70 regions, which were called M30 and M70, respectively. The remainder was defined by two elliptical areas with an eccentricity of 0.8, and 25 and 32 pixels of mayor axis (E25p and E32p, respectively). Twenty healthy males and 24 chronic obstructive pulmonary disease (COPD) patients were considered. For small region (P30 and M30) we obtained a large dispersion in volume measurement, concluding that small regions are not suitable for monitoring the tidal changes in lung volume even for healthy subjects. The results obtained by the remainder areas, and by using EIT image were similar. Even a slight improvement in data dispersion was obtained by using some ROI. These optimal results, for healthy people, were those corresponding to P70 and M70 (volume dispersion improved from 12% with the whole EIT image to 9% using ROI), and for COPD patients improves volume dispersion from 32% using the whole EIT image to 27% by using E25p. Using not so small ROI, it is possible to estimate the total lung ventilation. IntroductionIn clinical environment, there is nothing good enough to measure and monitor in a non-invasive manner the breathing pattern (BP), especially during large periods of time. The BP monitoring provides information about neuromuscular alterations suffered by patients and assesses organs that regulate breathing [1,2]. The reference method aimed to monitor the BP is the pneumotachometer. However, this device spontaneously modifies the behavior of respiration between 15% and 35% due to the essential use of a mouthpiece and clip-nose [3][4][5][6]. The pneumotachometer is mainly used in exercise stress testing in order to assess the pulmonary functional capacity during exercise. Other alternative method to monitor BP is the respiratory inductance plethysmography (RIP). This equipment is used to estimate lung volume by detecting respiratory movements of chest and abdominal wall. This method has been almost completely abandoned due to calibration problems [7][8][9]. Nowadays, this technique is used to monitor qualitatively respiration in patients with obstructive sleep apnea/hypopnea syndrome. A new experimental method used in clinical environment is the electrical impedance tomography (EIT). EIT is used to image regional impedance distribution in a cross-sectional...

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Measuring Breathing Pattern in Patients With Chronic Obstructive Pulmonary Disease by Electrical Impedance Tomography

Cited by 14 publications

References 13 publications

Electrical impedance tomography in acute lung injury

Electrical impedance tomography in acute lung injury

An accelerated version of alternating direction method of multipliers for TV minimization in EIT

Tidal volume monitoring by electrical impedance tomography (EIT) using different regions of interest (ROI): Calibration equations

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