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electrical impedance tomography

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https://www.readbyqxmd.com/read/28742775/estimation-of-stroke-volume-and-stroke-volume-changes-by-electrical-impedance-tomography
#1
Fernando José da Silva Ramos, André Hovnanian, Rogério Souza, Luciano C P Azevedo, Marcelo B P Amato, Eduardo L V Costa
BACKGROUND: Electrical impedance tomography (EIT) is a noninvasive imaging method that identifies changes in air and blood volume based on thoracic impedance changes. Recently, there has been growing interest in EIT to measure stroke volume (SV). The objectives of this study are as follows: (1) to evaluate the ability of systolic impedance variations (ΔZsys) to track changes in SV in relation to a baseline condition; (2) to assess the relationship of ΔZsys and SV in experimental subjects; and (3) to identify the influence of body dimensions on the relationship between ΔZsys and SV...
July 24, 2017: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/28742723/supraglottic-atomization-of-surfactant-in-spontaneously-breathing-lambs-receiving-continuous-positive-airway-pressure
#2
Ilaria Milesi, David G Tingay, Anna Lavizzari, Federico Bianco, Emanuela Zannin, Paolo Tagliabue, Fabio Mosca, Maria Luisa Ventura, Anushi Rajapaksa, Elizabeth J Perkins, Don Black, Marco Di Castri, Magdy Sourial, Gerhard Pohlmann, Raffaele L Dellaca'
OBJECTIVES: To determine the short-term tolerance, efficacy, and lung deposition of supraglottic atomized surfactant in spontaneously breathing lambs receiving continuous positive airway pressure. DESIGN: Prospective, randomized animal study. SETTING: Animal research laboratory. SUBJECTS: Twenty-two preterm lambs on continuous positive airway pressure (132 ± 1 d gestational age). INTERVENTIONS: Animals receiving continuous positive airway pressure via binasal prongs at 8 cm H2O were randomized to receive atomized surfactant at approximately 60-minute of life (atom; n = 15) or not (control; n = 7)...
July 22, 2017: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/28730574/mechanical-ventilation-guided-by-electrical-impedance-tomography-in-pediatric-acute-respiratory-distress-syndrome
#3
Jeffrey Dmytrowich, Tanya Holt, Karen Schmid, Gregory Hansen
Mechanical ventilation strategies in pediatric acute respiratory distress syndrome (pARDS) continue to advance. Optimizing positive end expiratory pressure (PEEP) and ventilation to recruitable lung can be difficult to clinically achieve. This is in part, due to disease evolution, unpredictable changes in lung compliance, and the inability to assess regional tidal volumes in real time at the bedside. Here we report the utilization of thoracic electrical impedance tomography to guide daily PEEP settings and recruitment maneuvers in a child with pARDS...
July 20, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28730554/bedside-selection-of-positive-end-expiratory-pressure-by-electrical-impedance-tomography-in-hypoxemic-patients-a-feasibility-study
#4
Nilde Eronia, Tommaso Mauri, Elisabetta Maffezzini, Stefano Gatti, Alfio Bronco, Laura Alban, Filippo Binda, Tommaso Sasso, Cristina Marenghi, Giacomo Grasselli, Giuseppe Foti, Antonio Pesenti, Giacomo Bellani
BACKGROUND: Positive end-expiratory pressure (PEEP) is a key element of mechanical ventilation. It should optimize recruitment, without causing excessive overdistension, but controversy exists on the best method to set it. The purpose of the study was to test the feasibility of setting PEEP with electrical impedance tomography in order to prevent lung de-recruitment following a recruitment maneuver. We enrolled 16 patients undergoing mechanical ventilation with PaO2/FiO2 <300 mmHg...
December 2017: Annals of Intensive Care
https://www.readbyqxmd.com/read/28726575/bioprinting-pattern-dependent-electrical-mechanical-behavior-of-cardiac-alginate-implants-characterization-and-ex-vivo-phase-contrast-microtomography-assessment
#5
Mohammad Izadifar, Paul Babyn, Michael E Kelly, Dean Chapman, Xiongbiao Chen
Three-dimensional (3D)-bioprinting techniques may be used to modulate electrical/mechanical properties and porosity of hydrogel constructs for fabrication of suitable cardiac implants. Notably, characterization of these properties after implantation remains a challenge, raising the need for the development of novel quantitative imaging techniques for monitoring hydrogel implant behavior in-situ. This study aims to (i) assess the influence of hydrogel bioprinting patterns on electrical/mechanical behavior of cardiac implants based on a 3D-printing technique and (ii) investigate the potential of synchrotron X-ray phase contrast computed tomography (PCI-CT) for estimating elastic modulus/impedance/porosity and microstructural features of 3D-printed cardiac implants in-situ via an ex-vivo study...
July 20, 2017: Tissue Engineering. Part C, Methods
https://www.readbyqxmd.com/read/28719759/airway-closure-could-be-confirmed-by-electrical-impedance-tomography
#6
Xiu-Mei Sun, Guang-Qiang Chen, Yi-Min Zhou, Yan-Lin Yang, Jian-Xin Zhou
No abstract text is available yet for this article.
July 18, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28715324/electrical-impedance-tomography-tissue-properties-to-image-measures
#7
Andy Adler, Alistair Boyle
Electrical Impedance Tomography (EIT) uses electrical stimulation and measurement at the body surface to image the electrical properties of internal tissues. It has the advantage of non-invasiveness and high temporal resolution but suffers from poor spatial resolution and sensitivity to electrode movement and contact quality. EIT can be useful to applications where there are conductive contrasts between tissues, fluids or gasses, such as imaging of cancerous or ischemic tissue or functional monitoring of breathing, blood flow, gastric motility and neural activity...
July 17, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28707173/intraoperative-ventilation-of-morbidly-obese-patients-guided-by-transpulmonary-pressure
#8
Lars Eichler, Katarzyna Truskowska, A Dupree, P Busch, Alwin E Goetz, Christian Zöllner
BACKGROUND: Bariatric surgery has proven a successful approach in the treatment of morbid obesity and its concomitant diseases such as diabetes mellitus and arterial hypertension. Aiming for optimal management of this challenging patient cohort, tailored concepts directly guided by individual patient physiology may outperform standardized care. Implying esophageal pressure measurement and electrical impedance tomography-increasingly applied monitoring approaches to individually adjust mechanical ventilation in challenging circumstances like acute respiratory distress syndrome (ARDS) and intraabdominal hypertension-we compared our institutions standard ventilator regimen with an individually adjusted positive end expiratory pressure (PEEP) level aiming for a positive transpulmonary pressure (P L) throughout the respiratory cycle...
July 14, 2017: Obesity Surgery
https://www.readbyqxmd.com/read/28697778/electrical-impedance-tomography-for-predicting-failure-of-spontaneous-breathing-trials-in-patients-with-prolonged-weaning
#9
Johannes Bickenbach, Michael Czaplik, Mareike Polier, Gernot Marx, Nikolaus Marx, Michael Dreher
BACKGROUND: Spontaneous breathing trials (SBTs) on a T-piece can be difficult in patients with prolonged weaning because of remaining de-recruitment phenomena and/or insufficient ventilation. There is no clinically established method existent other than experience for estimating whether an SBT is most probably beneficial. Electrical impedance tomography (EIT) is a clinical useful online monitoring technique during mechanical ventilation, particularly because it enables analysis of effects of regional ventilation distribution...
July 12, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28692972/tissue-acousto-electric-effect-modeling-from-solid-mechanics-theory
#10
Xizi Song, Yexian Qin, Yanbin Xu, Pier Ingram, Russell S Witte, Feng Dong
The acousto-electric (AE) effect is a basic physical phenomenon which underlies the changes made in the conductivity of a medium by the application of focused ultrasound. Recently, based on AE effect, several biomedical imaging techniques have been widely studied, such as ultrasound modulated electrical impedance tomography (UMEIT) and ultrasound current source density imaging (UCSDI). To further investigate the mechanism of the AE effect in tissue, and to provide guidance for such studies, we have modeled the tissue AE effect using the theory of solid mechanics...
July 7, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28676697/a-novel-3d-printed-head-phantom-with-anatomically-realistic-geometry-and-continuously-varying-skull-resistivity-distribution-for-electrical-impedance-tomography
#11
Jie Zhang, Bin Yang, Haoting Li, Feng Fu, Xuetao Shi, Xiuzhen Dong, Meng Dai
Phantom experiments are an important step for testing during the development of new hardware or imaging algorithms for head electrical impedance tomography (EIT) studies. However, due to the sophisticated anatomical geometry and complex resistivity distribution of the human head, constructing an accurate phantom for EIT research remains challenging, especially for skull modelling. In this paper, we designed and fabricated a novel head phantom with anatomically realistic geometry and continuously varying skull resistivity distribution based on 3D printing techniques...
July 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28653135/closed-loop-mechanical-ventilation-for-lung-injury-a-novel-physiological-feedback-mode-following-the-principles-of-the-open-lung-concept
#12
David Schwaiberger, Philipp A Pickerodt, Anake Pomprapa, Onno Tjarks, Felix Kork, Willehad Boemke, Roland C E Francis, Steffen Leonhardt, Burkhard Lachmann
Adherence to low tidal volume (VT) ventilation and selected positive end-expiratory pressures are low during mechanical ventilation for treatment of the acute respiratory distress syndrome. Using a pig model of severe lung injury, we tested the feasibility and physiological responses to a novel fully closed-loop mechanical ventilation algorithm based on the "open lung" concept. Lung injury was induced by surfactant washout in pigs (n = 8). Animals were ventilated following the principles of the "open lung approach" (OLA) using a fully closed-loop physiological feedback algorithm for mechanical ventilation...
June 26, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28632138/monitoring-lung-contusion-in-a-porcine-polytrauma-model-using-eit-an-application-study
#13
Susana Aguiar Santos, Carlos Castelar Wembers, Klemens Horst, Roman Pfeifer, Tim-Philipp Simon, Hans-Christoph Pape, Frank Hildebrand, Michael Czaplik, Steffen Leonhardt, Daniel Teichmann
Lung contusion is the most common lung injury following blunt chest trauma which, in turn, is associated with high mortality rates (Gavelli et al., 2002). Lung contusion is characterized by hemorrhage and edema with consecutively reduced compliance. In this study, unilateral lung contusion and other traumata were induced in 12 pigs by using a bolt gun machine. To investigate the pathophysiological consequences of lung contusion, information on clinical parameters was collected and monitored regularly while animals were additionally monitored with electrical impedance tomography (EIT) before trauma, and at 4, 24, 48 and 72 h after polytrauma...
June 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28628556/real-time-imaging-of-epileptic-seizures-in-rats-using-electrical-impedance-tomography
#14
Lei Wang, Yang Sun, Xinmin Xu, Xiuzhen Dong, Feng Gao
The presence of multiple or diffuse lesions on imaging is a contraindication to surgery for patients with intractable epilepsy. Theoretically, as a functional imaging technique, electrical impedance tomography (EIT) can accurately image epileptic foci. However, most current studies are limited to examining epileptic spikes and few studies use EIT for real-time imaging of seizure activity. Moreover, little is known about changes in electrical impedance during seizures. In this study, we used EIT to monitor seizure progression in real time and analyzed changes in electrical impedance during seizures...
August 2, 2017: Neuroreport
https://www.readbyqxmd.com/read/28614900/computational-method-for-estimating-boundary-of-abdominal-subcutaneous-fat-for-absolute-electrical-impedance-tomography
#15
Tohru F Yamaguchi, Yoshiwo Okamoto
Abdominal fat accumulation is considered an essential indicator of human health. Electrical impedance tomography has considerable potential for abdominal fat imaging because of the low specific conductivity of human body fat. In this paper, we propose a robust reconstruction method for high-fidelity conductivity imaging by abstraction of the abdominal cross section using a relatively small number of parameters. Toward this end, we assume homogeneous conductivity in the abdominal subcutaneous fat area, and characterize its geometrical shape by parameters defined as the ratio of the distance from the center to boundary of subcutaneous fat to the distance from the center to outer boundary in 64 equiangular directions...
June 14, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28604757/time-to-lung-aeration-during-a-sustained-inflation-at-birth-is-influenced-by-gestation-in-lambs
#16
Karen E McCall, Andreas D Waldmann, Prue Pereira-Fantini, Regina Oakley, M Miedema, Elizabeth J Perkins, Peter G Davis, Peter A Dargaville, Stephan H Böhm, Raffaele Dellacà, Magdy Sourial, Emanuela Zannin, Anushi Rajapaksa, Andre Tan, Andy Adler, Inéz Frerichs, David G Tingay
BACKGROUND: Current sustained lung inflation (SI) approaches use uniform pressures and durations. We hypothesised that gestational age related mechanical and developmental differences would affect the time required to achieve optimal lung aeration, and resultant lung volumes, during SI delivery at birth in lambs. METHODS: 49 lambs, in five cohorts between 118d and 139d gestation (term 142d), received a standardised 40 cmH2O SI, delivered until 10 s after lung volume stability (optimal aeration) was visualised on real-time electrical impedance tomography (EIT), or to a maximum duration of 180 s...
June 12, 2017: Pediatric Research
https://www.readbyqxmd.com/read/28578708/effects-of-neurally-adjusted-ventilatory-assist-on-air-distribution-and-dead-space-in-patients-with-acute-exacerbation-of-chronic-obstructive-pulmonary-disease
#17
Qin Sun, Ling Liu, Chun Pan, Zhanqi Zhao, Jingyuan Xu, Airan Liu, Haibo Qiu
BACKGROUND: Neurally adjusted ventilatory assist (NAVA) could improve patient-ventilator interaction; its effects on ventilation distribution and dead space are still unknown. The aim of this study was to evaluate the effects of varying levels of assist during NAVA and pressure support ventilation (PSV) on ventilation distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Fifteen mechanically ventilated patients with AECOPD were included in the study...
June 2, 2017: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/28572979/complex-effects-of-high-flow-nasal-cannula-therapy-on-hemodynamics-in-the-pediatric-patient-after-cardiac-surgery
#18
EDITORIAL
Yu Inata, Muneyuki Takeuchi
BACKGROUND: The high-flow nasal cannula (HFNC) system has been widely used for children in various clinical settings. However, the physiological and clinical impact of HFNC therapy on the pediatric patient with respiratory distress after cardiac surgery has not been thoroughly investigated. MAIN BODY OF THE ABSTRACT: It seems logical to use HFNC as a primary therapy for post-extubation respiratory failure after congenital heart surgery, in which low cardiac output syndrome and upper airway obstruction are commonly encountered; the HFNC therapy alleviates the work of breathing and large negative swings of intrathoracic pressure, which in turn helps to decrease the systemic ventricular afterload...
2017: Journal of Intensive Care
https://www.readbyqxmd.com/read/28564589/functional-monitoring-of-peripheral-nerves-from-electrical-impedance-measurements
#19
Alexandre Fouchard, Véronique Coizet, Valérie Sinniger, Didier Clarençon, Karin Pernet-Gallay, Stéphane Bonnet, Olivier David
Medical electrical stimulators adapted to peripheral nerves use multicontact cuff electrodes (MCC) to provide selective neural interfaces. However, neuroprostheses are currently limited by their inability to locate the regions of interest to focus. Intended until now either for stimulation or recording, MCC can also be used as a means of transduction to characterize the nerve by impedancemetry. In this study, we investigate the feasibility of using electrical impedance (EI) measurements as an in vivo functional nerve monitoring technique...
June 2, 2017: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/28560836/sensitivity-analysis-of-magnetic-field-measurements-for-magnetic-resonance-electrical-impedance-tomography-mreit
#20
Cihan Göksu, Klaus Scheffler, Philipp Ehses, Lars G Hanson, Axel Thielscher
PURPOSE: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (ΔBz,c ) is improved using systematic efficiency analyses and optimization of multi-echo spin echo (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. THEORY AND METHODS: Considering T1 , T2 , and T2* relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence parameters, are analytically analyzed and simulated...
May 30, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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