Abstract:
:Previous studies demonstrate that it is possible to evaluate a heart graft rejection condition using a bioimpedance technique by means of an intracavitary catheter. We propose to use a less invasive technique consisting in the use of a transoesophageal catheter and two standard ECG electrodes on the thorax. The aim of this work is to evaluate, using the finite element method, several parameters affecting the transoesophageal impedance measurement, including sensitivity to electrical conductivity and permittivity of different organs in the thorax, changes in magnitude and phase due to a lesion producing a scar, a global ischaemia of the heart, pleural effusion in the lungs, fat thickness increase, displacement of the catheter inside the oesophagus and movement of one electrode on the thorax surface. From these results, we deduce the best estimator for cardiac rejection detection and obtain the tools to identify eventual cases of false positives due to other factors. To achieve these objectives we have created a thoracic model and we have simulated different situations at the frequencies of 13, 30, 100, 300 and 1000 kHz. Our simulation demonstrates that the phase, at 100 and 300 kHz, would be a better estimator than the magnitude to evaluate a heart rejection condition.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Giovinazzo G,Ribas N,Cinca J,Rosell-Ferrer Jdoi
10.1088/0967-3334/32/7/S10subject
Has Abstractpub_date
2011-07-01 00:00:00pages
867-76issue
7eissn
0967-3334issn
1361-6579pii
S0967-3334(11)69757-2journal_volume
32pub_type
杂志文章abstract::Multiple frequency bio-electrical impedance analysis (MFBIA) may be useful for monitoring fluid balance in newborn infants or to provide early prediction of the outcome following perinatal asphyxia. A reference range of data is needed for identification of babies with abnormal impedance values. This was a cross-sectio...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/11/010
更新日期:2006-11-01 00:00:00
abstract::Spirometry is the gold standard to determine the presence of airflow obstruction, but it requires volitional participation and needs qualified supervision. The forced oscillation technique (FOT) measures respiratory input impedance (Zrs) during spontaneous breathing and it could be useful for unsupervised monitoring o...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/31/4/N01
更新日期:2010-04-01 00:00:00
abstract::Although people spend a third of their day engaged in sedentary activities, research on heart activity during sitting is almost nonexistent because of the discomfort experienced when electrocardiogram (ECG) measurement electrodes are attached to the body. Accordingly, in this study, a system was developed to monitor h...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/3/N61
更新日期:2015-03-01 00:00:00
abstract::Dual-energy x-ray absorptiometry (DXA) is a precise, widely used method for measuring bone mineral density (BMD), usually of the lumbar spine and femoral neck. Recent developments, such as a lower x-ray tube current and pixel by pixel analysis, enable smaller bones and thinner tissues volumes, as in the hand, to be me...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/18/3/008
更新日期:1997-08-01 00:00:00
abstract::Fetal hiccups emerge as early as nine weeks post-conception, being the predominant diaphragmatic movement before 26 weeks of gestation. They are considered as a programmed isometric inspiratory muscle exercise of the fetus in preparation for the post-natal respiratory function, or a manifestation of a reflex circuitry...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/6/005
更新日期:2007-06-01 00:00:00
abstract::The outflow conductance (C(out)) of the cerebrospinal fluid (CSF) system is a parameter considered to be predictive in selection for hydrocephalus surgery. C(out) can be determined through an infusion test. A new apparatus for performing infusion tests in a standardized and automated way was developed. The objective w...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/6/022
更新日期:2005-12-01 00:00:00
abstract:OBJECTIVE:Non-contact physiological measurement is a growing research area that allows capturing vital signs such as heart rate (HR) and breathing rate (BR) comfortably and unobtrusively with remote devices. However, most of the approaches work only in bright environments in which subtle photoplethysmographic and balli...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aae625
更新日期:2018-10-30 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章,评审
doi:10.1088/1361-6579/ab0096
更新日期:2019-02-26 00:00:00
abstract:OBJECTIVE:To investigate if modern seismocardiography (SCG) and ballistocardiography (BCG) are useful in the detection of hemodynamic changes occurring during simulated obstructive apneic events. METHODS:Forty-seven healthy volunteers performed a voluntary maximum Mueller maneuver (MM) for 10 s, and SCG and BCG signal...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab924b
更新日期:2020-07-09 00:00:00
abstract::Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum t...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/12/008
更新日期:2009-12-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/11/N02
更新日期:2011-11-01 00:00:00
abstract::Imaging photoplethysmography is a relatively new technique for extracting biometric information from video images of faces. This is useful in non-invasive monitoring of patients including neonates or the aged, with respect to sudden infant death syndrome, sleep apnoea, pulmonary disease, physical or mental stress and ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/1/67
更新日期:2015-01-01 00:00:00
abstract::The transthoracic electrical impedance is an important defibrillation parameter, affecting the defibrillating current amplitude and energy, and therefore the defibrillation efficiency. A close relationship between transthoracic impedance and defibrillation success rate was observed. Pre-shock measurements (using low a...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/21/1/318
更新日期:2000-02-01 00:00:00
abstract::ECG-gated electrical impedance tomographic spectroscopy (EITS) measurements of the lungs were taken on seven normal subjects in the frequency range 9.6 kHz to 614.4 kHz. The results show that in late systole the resistivity p' relative to the R-wave (i.e. p' = 1 at the R-wave) decreases consistently within the lung. I...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/17/4a/026
更新日期:1996-11-01 00:00:00
abstract::The activPAL™ activity monitor has potential for use in youth with Cerebral Palsy (CP) as it has demonstrated acceptable validity for the assessment of sedentary and physical activity in other populations. This study determined the validity of the activPAL™ activity monitor for the measurement of sitting, standing, wa...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/11/2307
更新日期:2014-11-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab9c70
更新日期:2020-08-11 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/10/014
更新日期:2011-10-01 00:00:00
abstract::The electrocardiogram (ECG) is a well studied signal from which many clinically relevant parameters can be derived, such as heart rate. A key component in the estimation of these parameters is the accurate detection of the R peak in the QRS complex. While corruption of the ECG by movement artefact or sensor failure ca...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/8/1665
更新日期:2015-08-01 00:00:00
abstract:OBJECTIVE:As the global burden of cardiovascular disease increases, proactive cardiovascular healthcare by means of accurate, precise, continuous, and non-invasive monitoring is becoming crucial. However, no current device is able to provide cardiac hemodynamic monitoring with the aforementioned criterion. Electrical i...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abb141
更新日期:2020-10-06 00:00:00
abstract::The use of artificial neural networks (ANNs) to interpret sleep monitoring signals is described. Recordings from ten infants with apparent life threatening episodes were assigned into training feedforward R-PROP networks. In order to separate good signal from artefact, 60 second time frames of SaO2 and TcPO2 signals w...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/21/3/401
更新日期:2000-08-01 00:00:00
abstract::Temporal changes in the impedance spectra of bioelectrodes in contact with skin provide useful data for comparisons between differing electrode materials and skin preparation methods. Traditional impedance measuring systems employ swept frequency methods which will distort results in the impedance spectra of a sample ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/20/1/008
更新日期:1999-02-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/24/2/367
更新日期:2003-05-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/16/3a/009
更新日期:1995-08-01 00:00:00
abstract:OBJECTIVE:Observational studies suggest that obesity might have a Mendelian origin, but it is not clear if gene expression patterns observed in obese subjects are secondary to genetic traits or not. APPROACH:Here we test a transcriptomic signature of obesity previously identified by our group on a large cohort of twin...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aab85a
更新日期:2018-04-26 00:00:00
abstract::Electrical impedance tomography (EIT) is very sensitive to deformations of the medium boundary shape. For lung imaging, breathing and changes in posture move the electrodes and change the chest shape, resulting in image artefacts. Several approaches have been proposed to improve the reconstructed images; most methods ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/6/S08
更新日期:2008-06-01 00:00:00
abstract::The recently-introduced technique of detrended fluctuation analysis (DFA) for heart-rate variability appears to yield improved prognostic power in cardiovascular disease through calculation of the fractal scaling exponent alpha. However, the physiological meaning of alpha remains unclear. In DFA, the signal is segment...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/23/2/314
更新日期:2002-05-01 00:00:00
abstract::Neuromagnetic recordings were used to check if electrical stimulation of the auditory nerve in cochlear-implant patients activates cortical auditory areas in a similar manner as acoustic stimulation in normal hearing subjects or whether the excitation processes are different. The waveform of the evoked magnetic field ...
journal_title:Physiological measurement
pub_type: 杂志文章,评审
doi:10.1088/0967-3334/14/4a/014
更新日期:1993-11-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/8/1298
更新日期:2016-08-01 00:00:00
abstract::Electrical impedance tomography (EIT) has the potential to become a new tool for bedside monitoring of regional lung ventilation. The aim of our study was to assess the reproducibility of regional lung ventilation distribution determined by EIT during mechanical ventilation under identical ventilator settings. The exp...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/7/S19
更新日期:2007-07-01 00:00:00
abstract::Neural gastric electrical stimulation (NGES) is a new method for invoking gastric contractions under microprocessor control. However, optimization of this technique using feedback mechanisms to minimize power consumption and maximize effectiveness has been lacking. The present pilot study proposes a prototype feedback...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/3/006
更新日期:2009-03-01 00:00:00