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Wang K, Margolis S, Cho JM, Wang S, Arianpour B, Jabalera A, Yin J, Hong W, Zhang Y, Zhao P, Zhu E, Reddy S, Hsiai TK. Non-Invasive Detection of Early-Stage Fatty Liver Disease via an On-Skin Impedance Sensor and Attention-Based Deep Learning. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2400596. [PMID: 38887178 DOI: 10.1002/advs.202400596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/17/2024] [Indexed: 06/20/2024]
Abstract
Early-stage nonalcoholic fatty liver disease (NAFLD) is a silent condition, with most cases going undiagnosed, potentially progressing to liver cirrhosis and cancer. A non-invasive and cost-effective detection method for early-stage NAFLD detection is a public health priority but challenging. In this study, an adhesive, soft on-skin sensor with low electrode-skin contact impedance for early-stage NAFLD detection is fabricated. A method is developed to synthesize platinum nanoparticles and reduced graphene quantum dots onto the on-skin sensor to reduce electrode-skin contact impedance by increasing double-layer capacitance, thereby enhancing detection accuracy. Furthermore, an attention-based deep learning algorithm is introduced to differentiate impedance signals associated with early-stage NAFLD in high-fat-diet-fed low-density lipoprotein receptor knockout (Ldlr-/-) mice compared to healthy controls. The integration of an adhesive, soft on-skin sensor with low electrode-skin contact impedance and the attention-based deep learning algorithm significantly enhances the detection accuracy for early-stage NAFLD, achieving a rate above 97.5% with an area under the receiver operating characteristic curve (AUC) of 1.0. The findings present a non-invasive approach for early-stage NAFLD detection and display a strategy for improved early detection through on-skin electronics and deep learning.
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Affiliation(s)
- Kaidong Wang
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Medicine, Greater Los Angeles Veterans Affairs (VA) Healthcare System, Los Angeles, CA, 90073, USA
| | - Samuel Margolis
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Jae Min Cho
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Shaolei Wang
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Brian Arianpour
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Alejandro Jabalera
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Junyi Yin
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Wen Hong
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Yaran Zhang
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Peng Zhao
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Enbo Zhu
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Srinivasa Reddy
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Tzung K Hsiai
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Medicine, Greater Los Angeles Veterans Affairs (VA) Healthcare System, Los Angeles, CA, 90073, USA
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Cabezudo Ballesteros S, Sanabria Carretero P, Reinoso Barbero F. Review of electrical impedance tomography in the pediatric patient. REVISTA ESPANOLA DE ANESTESIOLOGIA Y REANIMACION 2024; 71:479-485. [PMID: 38458492 DOI: 10.1016/j.redare.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 08/28/2023] [Indexed: 03/10/2024]
Abstract
Electrical impedance tomography (EIT) is a new method of monitoring non-invasive mechanical ventilation, at the bedside and useful in critically ill patients. It allows lung monitoring of ventilation and perfusion, obtaining images that provide information on lung function. It is based on the physical principle of impedanciometry or the body's ability to conduct an electrical current. Various studies have shown its usefulness both in adults and in pediatrics in respiratory distress syndrome, pneumonia and atelectasis in addition to pulmonary thromboembolism and pulmonary hypertension by also providing information on pulmonary perfusion, and may be very useful in perioperative medicine; especially in pediatrics avoiding repetitive imaging tests with ionizing radiation.
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Affiliation(s)
| | - P Sanabria Carretero
- Servicio de Anestesia y Reanimación, Hospital Universitario La Paz, Madrid, Spain
| | - F Reinoso Barbero
- Servicio de Anestesia y Reanimación, Hospital Universitario La Paz, Madrid, Spain
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Onsager CC, Wang C, Costakis C, Aygen CC, Lang L, van der Lee S, Grayson MA. Sensitivity volume as figure-of-merit for maximizing data importance in electrical impedance tomography. Physiol Meas 2024; 45:045004. [PMID: 38624240 DOI: 10.1088/1361-6579/ad3458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 03/15/2024] [Indexed: 04/17/2024]
Abstract
Objective.Electrical impedance tomography (EIT) is a noninvasive imaging method whereby electrical measurements on the periphery of a heterogeneous conductor are inverted to map its internal conductivity. The EIT method proposed here aims to improve computational speed and noise tolerance by introducing sensitivity volume as a figure-of-merit for comparing EIT measurement protocols.Approach.Each measurement is shown to correspond to a sensitivity vector in model space, such that the set of measurements, in turn, corresponds to a set of vectors that subtend a sensitivity volume in model space. A maximal sensitivity volume identifies the measurement protocol with the greatest sensitivity and greatest mutual orthogonality. A distinguishability criterion is generalized to quantify the increased noise tolerance of high sensitivity measurements.Main result.The sensitivity volume method allows the model space dimension to be minimized to match that of the data space, and the data importance to be increased within an expanded space of measurements defined by an increased number of contacts.Significance.The reduction in model space dimension is shown to increasecomputational efficiency, accelerating tomographic inversion by several orders of magnitude, while the enhanced sensitivitytolerates higher noiselevels up to several orders of magnitude larger than standard methods.
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Affiliation(s)
- Claire C Onsager
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - Chulin Wang
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - Charles Costakis
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - Can C Aygen
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - Lauren Lang
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
| | - Suzan van der Lee
- Department of Earth and Planetary Sciences, Northwestern University, Evanston IL, United States of America
| | - Matthew A Grayson
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States of America
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Gatti S, Rezoagli E, Madotto F, Foti G, Bellani G. A non-invasive continuous and real-time volumetric monitoring in spontaneous breathing subjects based on bioimpedance-ExSpiron®Xi: a validation study in healthy volunteers. J Clin Monit Comput 2024; 38:539-551. [PMID: 38238635 PMCID: PMC10994998 DOI: 10.1007/s10877-023-01107-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 11/10/2023] [Indexed: 04/06/2024]
Abstract
Tidal volume (TV) monitoring breath-by-breath is not available at bedside in non-intubated patients. However, TV monitoring may be useful to evaluate the work of breathing. A non-invasive device based on bioimpedance provides continuous and real-time volumetric tidal estimation during spontaneous breathing. We performed a prospective study in healthy volunteers aimed at evaluating the accuracy, the precision and the trending ability of measurements of ExSpiron®Xi as compared with the gold standard (i.e. spirometry). Further, we explored whether the differences between the 2 devices would be improved by the calibration of ExSpiron®Xi with a pre-determined tidal volume. Analysis accounted for the repeated nature of measurements within each subject. We enrolled 13 healthy volunteers, including 5 men and 8 women. Tidal volume, TV/ideal body weight (IBW) and respiratory rate (RR) measured with spirometer (TVSpirometer) and with ExSpiron®Xi (TVExSpiron) showed a robust correlation, while minute ventilation (MV) showed a weak correlation, in both non/calibrated and calibrated steps. The analysis of the agreement showed that non-calibrated TVExSpiron underestimated TVspirometer, while in the calibrated steps, TVExSpiron overestimated TVspirometer. The calibration procedure did not reduce the average absolute difference (error) between TVSpirometer and TVExSpiron. This happened similarly for TV/IBW and MV, while RR showed high accuracy and precision. The trending ability was excellent for TV, TV/IBW and RR. The concordance rate (CR) was >95% in both calibrated and non-calibrated measurements. The trending ability of minute ventilation was limited. Absolute error for both calibrated and not calibrated values of TV, TV/IBW and MV accounting for repeated measurements was variably associated with BMI, height and smoking status. Conclusions: Non-invasive TV, TV/IBW and RR estimation by ExSpiron®Xi was strongly correlated with tidal ventilation according to the gold standard spirometer technique. This data was not confirmed for MV. The calibration of the device did not improve its performance. Although the accuracy of ExSpiron®Xi was mild and the precision was limited for TV, TV/IBW and MV, the trending ability of the device was strong specifically for TV, TV/IBW and RR. This makes ExSpiron®Xi a non-invasive monitoring system that may detect real-time tidal volume ventilation changes and then suggest the need to better optimize the patient ventilatory support.
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Affiliation(s)
- Stefano Gatti
- Department of Emergency and Intensive Care, Terapia Intensiva e Semintensiva adulti e Pediatrica, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
| | - Emanuele Rezoagli
- Department of Emergency and Intensive Care, Terapia Intensiva e Semintensiva adulti e Pediatrica, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Fabiana Madotto
- Department of Area Emergenza Urgenza, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milan, Italy
| | - Giuseppe Foti
- Department of Emergency and Intensive Care, Terapia Intensiva e Semintensiva adulti e Pediatrica, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Giacomo Bellani
- Centre for Medical Sciences - CISMed, University of Trento, Trento, Italy.
- Anesthesia and Intensive Care, Santa Chiara Regional Hospital, APSS Trento Largo Medaglie d'Oro, Trento, Italy.
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Hyun CM, Kim TG, Lee K. Unsupervised sequence-to-sequence learning for automatic signal quality assessment in multi-channel electrical impedance-based hemodynamic monitoring. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 247:108079. [PMID: 38394789 DOI: 10.1016/j.cmpb.2024.108079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/08/2023] [Accepted: 02/11/2024] [Indexed: 02/25/2024]
Abstract
BACKGROUND AND OBJECTIVE This study proposes an unsupervised sequence-to-sequence learning approach that automatically assesses the motion-induced reliability degradation of the cardiac volume signal (CVS) in multi-channel electrical impedance-based hemodynamic monitoring. The proposed method attempts to tackle shortcomings in existing learning-based assessment approaches, such as the requirement of manual annotation for motion influence and the lack of explicit mechanisms for realizing motion-induced abnormalities under contextual variations in CVS over time. METHOD By utilizing long-short term memory and variational auto-encoder structures, an encoder-decoder model is trained not only to self-reproduce an input sequence of the CVS but also to extrapolate the future in a parallel fashion. By doing so, the model can capture contextual knowledge lying in a temporal CVS sequence while being regularized to explore a general relationship over the entire time-series. A motion-influenced CVS of low-quality is detected, based on the residual between the input sequence and its neural representation with a cut-off value determined from the two-sigma rule of thumb over the training set. RESULT Our experimental observations validated two claims: (i) in the learning environment of label-absence, assessment performance is achievable at a competitive level to the supervised setting, and (ii) the contextual information across a time series of CVS is advantageous for effectively realizing motion-induced unrealistic distortions in signal amplitude and morphology. We also investigated the capability as a pseudo-labeling tool to minimize human-craft annotation by preemptively providing strong candidates for motion-induced anomalies. Empirical evidence has shown that machine-guided annotation can reduce inevitable human-errors during manual assessment while minimizing cumbersome and time-consuming processes. CONCLUSION The proposed method has a particular significance in the industrial field, where it is unavoidable to gather and utilize a large amount of CVS data to achieve high accuracy and robustness in real-world applications.
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Affiliation(s)
- Chang Min Hyun
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; School of Mathematics and Computing (Computational Science and Engineering), Yonsei University, Seoul, Republic of Korea.
| | - Tae-Geun Kim
- Department of Physics, Yonsei University, Seoul, Republic of Korea
| | - Kyounghun Lee
- Medical Science Research Institute, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea.
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Byrne DP, Studer N, Secombe C, Cieslewicz A, Hosgood G, Raisis A, Adler A, Mosing M. Validation of three-dimensional thoracic electrical impedance tomography of horses during normal and increased tidal volumes. Physiol Meas 2024; 45:035010. [PMID: 38422515 DOI: 10.1088/1361-6579/ad2eb3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
Objective. Data from two-plane electrical impedance tomography (EIT) can be reconstructed into various slices of functional lung images, allowing for more complete visualisation and assessment of lung physiology in health and disease. The aim of this study was to confirm the ability of 3D EIT to visualise normal lung anatomy and physiology at rest and during increased ventilation (represented by rebreathing).Approach. Two-plane EIT data, using two electrode planes 20 cm apart, were collected in 20 standing sedate horses at baseline (resting) conditions, and during rebreathing. EIT data were reconstructed into 3D EIT whereby tidal impedance variation (TIV), ventilated area, and right-left and ventral-dorsal centres of ventilation (CoVRLand CoVVD, respectively) were calculated in cranial, middle and caudal slices of lung, from data collected using the two planes of electrodes.Main results. There was a significant interaction of time and slice for TIV (p< 0.0001) with TIV increasing during rebreathing in both caudal and middle slices. The ratio of right to left ventilated area was higher in the cranial slice, in comparison to the caudal slice (p= 0.0002). There were significant effects of time and slice on CoVVDwhereby the cranial slice was more ventrally distributed than the caudal slice (p< 0.0009 for the interaction).Significance. The distribution of ventilation in the three slices corresponds with topographical anatomy of the equine lung. This study confirms that 3D EIT can accurately represent lung anatomy and changes in ventilation distribution during rebreathing in standing sedate horses.
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Affiliation(s)
- David P Byrne
- School of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, Australia
| | | | - Cristy Secombe
- School of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, Australia
| | | | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, Australia
| | - Anthea Raisis
- School of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, Australia
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottowa, ON, Canada
| | - Martina Mosing
- Anaesthesia and Perioperative Intensive Care, Department of Companion Animals and Horses Vetmeduni, Vienna, Austria
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Manuel AC, Vela JLP, Gude MJL, Otaegui NB. Usefulness of Monitoring Ventilation-Perfusion With Electrical Impedance Tomography in the Immediate Postoperative Period after Pulmonary Thromboendarterectomy. J Cardiothorac Vasc Anesth 2024; 38:796-801. [PMID: 38195273 DOI: 10.1053/j.jvca.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 12/02/2023] [Accepted: 12/07/2023] [Indexed: 01/11/2024]
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Schroeder L, Kipfmueller F, Hentze B, Putensen C, Bagci S, Dresbach T, Sabir H, Mueller A, Muders T. Evaluation of Regional Ventilation Distributions in Newborns with Congenital Diaphragmatic Hernia. Am J Respir Crit Care Med 2024; 209:601-606. [PMID: 38047881 DOI: 10.1164/rccm.202305-0797le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/30/2023] [Indexed: 12/05/2023] Open
Affiliation(s)
- Lukas Schroeder
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Florian Kipfmueller
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Benjamin Hentze
- Department of Anesthesiology and Operative Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
- RWTH Aachen University, Helmholtz Institute for Biomedical Engineering, Aachen, Germany
| | - Christian Putensen
- Department of Anesthesiology and Operative Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Soyhan Bagci
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Till Dresbach
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Hemmen Sabir
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Andreas Mueller
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children's Hospital Bonn, Bonn, Germany
| | - Thomas Muders
- Department of Anesthesiology and Operative Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
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Cervantes A, Paez G, Balleza-Ordaz JM, Vargas-Luna FM, Kashina S. Electrical bioimpedance analysis and comparison in biological tissues through crystalloid solutions implementation. Biosens Bioelectron 2024; 246:115874. [PMID: 38039732 DOI: 10.1016/j.bios.2023.115874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023]
Abstract
Electrical bioimpedance is a non-invasive and radiation-free technique that was proposed to be used in different clinical areas, however, its practical use is limited due to its low capacity to discriminate between tissues. In order to overcome this limitation, our research group proposes to incorporate the contrast media into the electrical bioimpedance procedure. The main objective of the present study was to assess the crystalloid solutions as a possible contrast media to discriminate between different tissue types in the bioimpedance technique. Two medical-grade crystalloid solutions (Hartmann and NaCl 0.9%) were injected into three biological ex vivo models: kidney, liver, and brain. BIOPAC system was used to acquire bioimpedance data before and after the injections. The data was adjusted to the Debye electrical model. The analysis of measured values showed substantial bioimpedance disparities in tissues subjected to isotonic solutions. The NaCl solution exhibited more pronounced changes in electrical parameters compared to the Hartmann solution. Similarly, NaCl solution displayed superior discriminatory capabilities among tissues, with variations of 465%, 157%, and 206%. Distinct spectral modifications were identified, with tissues demonstrating unique responses at each frequency of analysis relative to untreated tissue. Variations in bandwidth alterations were discernible among tissues, providing clear distinctions. In conclusion, the research showed that the crystalloid solution exhibited greater sensitivity and superior tissue contrast at specific frequencies. This study's findings underscore the feasibility of implementing crystalloid solutions to enhance tissue discrimination, similar to the effects of contrast agents.
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Affiliation(s)
- Andrea Cervantes
- Science and Engineering Division, University of Guanajuato, León, Guanajuato, 37150, Mexico
| | - Gonzalo Paez
- Center for Research in Optics, León, Guanajuato, 37150, Mexico.
| | | | | | - Svetlana Kashina
- Science and Engineering Division, University of Guanajuato, León, Guanajuato, 37150, Mexico.
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Chung CR, Ko RE, Jang GY, Lee K, Suh GY, Kim Y, Woo EJ. Comparison of noninvasive cardiac output and stroke volume measurements using electrical impedance tomography with invasive methods in a swine model. Sci Rep 2024; 14:2962. [PMID: 38316842 PMCID: PMC10844629 DOI: 10.1038/s41598-024-53488-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 02/01/2024] [Indexed: 02/07/2024] Open
Abstract
Pulmonary artery catheterization (PAC) has been used as a clinical standard for cardiac output (CO) measurements on humans. On animals, however, an ultrasonic flow sensor (UFS) placed around the ascending aorta or pulmonary artery can measure CO and stroke volume (SV) more accurately. The objective of this paper is to compare CO and SV measurements using a noninvasive electrical impedance tomography (EIT) device and three invasive devices using UFS, PAC-CCO (continuous CO) and arterial pressure-based CO (APCO). Thirty-two pigs were anesthetized and mechanically ventilated. A UFS was placed around the pulmonary artery through thoracotomy in 11 of them, while the EIT, PAC-CCO and APCO devices were used on all of them. Afterload and contractility were changed pharmacologically, while preload was changed through bleeding and injection of fluid or blood. Twenty-three pigs completed the experiment. Among 23, the UFS was used on 7 pigs around the pulmonary artery. The percentage error (PE) between COUFS and COEIT was 26.1%, and the 10-min concordance was 92.5%. Between SVUFS and SVEIT, the PE was 24.8%, and the 10-min concordance was 94.2%. On analyzing the data from all 23 pigs, the PE between time-delay-adjusted COPAC-CCO and COEIT was 34.6%, and the 10-min concordance was 81.1%. Our results suggest that the performance of the EIT device in measuring dynamic changes of CO and SV on mechanically-ventilated pigs under different cardiac preload, afterload and contractility conditions is at least comparable to that of the PAC-CCO device. Clinical studies are needed to evaluate the utility of the EIT device as a noninvasive hemodynamic monitoring tool.
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Affiliation(s)
- Chi Ryang Chung
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ryoung Eun Ko
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Geuk Young Jang
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea
| | - Kyounghun Lee
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea
| | - Gee Young Suh
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yongmin Kim
- Department of Convergence IT Engineering, POSTECH, Pohang, Korea
| | - Eung Je Woo
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea.
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佘 林, 周 睿, 潘 盼, 李 展, 刘 继, 谢 菲. [Research progress on electrical impedance tomography in pulmonary perfusion]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2023; 40:1249-1254. [PMID: 38151950 PMCID: PMC10753299 DOI: 10.7507/1001-5515.202302025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 10/04/2023] [Indexed: 12/29/2023]
Abstract
Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring based on the impedance differences of different tissues and organs in the human body. It has been initially applied in clinical research as well as disease diagnosis and treatment. Lung perfusion refers to the blood flow perfusion function of lung tissue, and the occurrence and development of many diseases are closely related to lung perfusion. Therefore, real-time monitoring of lung perfusion is particularly important. The application and development of EIT further promote the monitoring of lung perfusion, and related research has made great progress. This article reviews the principles of EIT imaging, lung perfusion imaging methods, and their clinical applications in recent years, with the aim of providing assistance to clinical and scientific researchers.
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Affiliation(s)
- 林君 佘
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
| | - 睿 周
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
| | - 盼 潘
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
| | - 展 李
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
| | - 继红 刘
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
| | - 菲 谢
- 河南中医药大学 第一临床医学院(郑州 450000)The First Clinical Medical College, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, P. R. China
- 中国人民解放军总医院第一医学中心 呼吸与危重症医学科(北京 100091)Department of Respiratory and Critical Care Medicine, The First Medical Center of Chinese PLA General Hospital, Beijing 100091, P. R. China
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Bosch-Compte R, Parrilla FJ, Muñoz-Bermúdez R, Dot I, Climent C, Masclans JR, Marin-Corral J, Pérez-Terán P. Comparing lung aeration and respiratory effort using two different spontaneous breathing trial: T-piece vs pressure support ventilation. Med Intensiva 2023:S2173-5727(23)00131-5. [PMID: 37798153 DOI: 10.1016/j.medine.2023.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 10/07/2023]
Abstract
OBJECTIVE To assess the changes in lung aeration and respiratory effort generated by two different spontaneous breathing trial (SBT): T-piece (T-T) vs pressure support ventilation (PSV). DESIGN Prospective, interventionist and randomized study. SETTING Intensive Care Unit (ICU) of Hospital del Mar. PARTICIPANTS Forty-three ventilated patients for at least 24 h and considered eligible for an SBT were included in the study between October 2017 and March 2020. INTERVENTIONS 30-min SBT with T-piece (T-T group, 20 patients) or 8-cmH2O PSV and 5-cmH2O positive end expiratory pressure (PSV group, 23 patients). MAIN VARIABLES OF INTEREST Demographics, clinical data, physiological variables, lung aeration evaluated with electrical impedance tomography (EIT) and lung ultrasound (LUS), and respiratory effort using diaphragmatic ultrasonography (DU) were collected at different timepoints: basal (BSL), end of SBT (EoSBT) and one hour after extubation (OTE). RESULTS There were a loss of aeration measured with EIT and LUS in the different study timepoints, without statistical differences from BSL to OTE, between T-T and PSV [LUS: 3 (1, 5.5) AU vs 2 (1, 3) AU; p = 0.088; EELI: -2516.41 (-5871.88, 1090.46) AU vs -1992.4 (-3458.76, -5.07) AU; p = 0.918]. Percentage of variation between BSL and OTE, was greater when LUS was used compared to EIT (68.1% vs 4.9%, p ≤ 0.001). Diaphragmatic excursion trend to decrease coinciding with a loss of aeration during extubation. CONCLUSION T-T and PSV as different SBT strategies in ventilated patients do not show differences in aeration loss, nor estimated respiratory effort or tidal volume measured by EIT, LUS and DU.
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Affiliation(s)
- Raquel Bosch-Compte
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain.
| | - Francisco José Parrilla
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Rosana Muñoz-Bermúdez
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Irene Dot
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Cristina Climent
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Joan Ramon Masclans
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain; Medicine and Life Sciences Department (MELIS), Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Judith Marin-Corral
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain; Division of Pulmonary Diseases & Critical Care Medicine, South Texas Veterans Health Care System and University of Texas Health San Antonio, San Antonio, TX, USA
| | - Purificación Pérez-Terán
- Critical Care Department, Hospital del Mar, Critical Illness Research Group (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
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Benites MH, Torres D, Poblete F, Labbe F, Bachmann MC, Regueira TE, Soto L, Ferre A, Dreyse J, Retamal J. Effects of changes in trunk inclination on ventilatory efficiency in ARDS patients: quasi-experimental study. Intensive Care Med Exp 2023; 11:65. [PMID: 37755538 PMCID: PMC10533449 DOI: 10.1186/s40635-023-00550-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 09/12/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Trunk inclination from semirecumbent head-upright to supine-flat positioning reduces driving pressure and increases respiratory system compliance in patients with acute respiratory distress syndrome (ARDS). These effects are associated with an improved ventilatory ratio and reduction in the partial pressure of carbon dioxide (PaCO2). However, these physiological effects have not been completely studied, and their mechanisms have not yet been elucidated. Therefore, this study aimed to evaluate the effects of a change in trunk inclination from semirecumbent (45°) to supine-flat (10°) on physiological dead space and ventilation distribution in different lung regions. RESULTS Twenty-two ARDS patients on pressure-controlled ventilation underwent three 60-min steps in which trunk inclination was changed from 45° (baseline) to 10° (intervention) and back to 45° (control) in the last step. Tunk inclination from a semirecumbent (45°) to a supine-flat (10°) position resulted in a higher tidal volume [371 (± 76) vs. 433 (± 84) mL (P < 0.001)] and respiratory system compliance [34 (± 10) to 41 (± 12) mL/cmH2O (P < 0.001)]. The CO2 exhaled per minute improved from 191 mL/min (± 34) to 227 mL/min (± 38) (P < 0.001). Accordingly, Bohr's dead space ratio decreased from 0.49 (± 0.07) to 0.41 (± 0.06) (p < 0.001), and PaCO2 decreased from 43 (± 5) to 36 (± 4) mmHg (p < 0.001). In addition, the impedance ratio, which divides the ventilation activity of the ventral region by the dorsal region ventilation activity in tidal images, dropped from 1.27 (0.83-1.78) to 0.86 (0.51-1.33) (p < 0.001). These results, calculated from functional EIT images, indicated further ventilation activity in the dorsal lung regions. These effects rapidly reversed once the patient was repositioned at 45°. CONCLUSIONS A change in trunk inclination from a semirecumbent (45 degrees) to a supine-flat position (10 degrees) improved Bohr's dead space ratio and reduced PaCO2 in patients with ARDS. This effect is associated with an increase in tidal volume and respiratory system compliance, along with further favourable impedance ventilation distribution toward the dorsal lung regions. This study highlights the importance of considering trunk inclination as a modifiable determinant of physiological parameters. The angle of trunk inclination is essential information that must be reported in ARDS patients.
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Affiliation(s)
- Martín H Benites
- Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile
- Departamento de Epidemiología y Estudios en Salud, Magíster en Epidemiología, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile
- Estudiante del Programa Doctorado en Ciencias Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile
- Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile
| | - David Torres
- Departamento de Epidemiología y Estudios en Salud, Magíster en Epidemiología, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile
| | - Fabian Poblete
- Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile
| | - Francisco Labbe
- Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile
| | - María C Bachmann
- Estudiante del Programa Doctorado en Ciencias Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile
- Departamento de Medicina Intensiva, Hospital Clínico Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile
| | - Tomas E Regueira
- Unidad de Pacientes Críticos, Clínica Santa María, Bellavista 415, Santiago, Chile
| | - Leonardo Soto
- Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile
- Unidad de Pacientes Críticos, Clínica Santa María, Bellavista 415, Santiago, Chile
| | - Andrés Ferre
- Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile
- Facultad de Medicina, Escuela de Medicina, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Santiago, Chile
| | - Jorge Dreyse
- Unidad de Pacientes Críticos, Clínica Las Condes, Estoril 450, Santiago, Chile
| | - Jaime Retamal
- Departamento de Medicina Intensiva, Hospital Clínico Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile.
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14
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Öner Ö, Ergan B, Kizil AS, Gurkok MC, Dugral E, Gökmen N. Investigation of high flow nasal cannule efficiency with electric impedance tomography based parameters in COVID-19 adults patients: a retrospective study. PeerJ 2023; 11:e15555. [PMID: 37465153 PMCID: PMC10351510 DOI: 10.7717/peerj.15555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 05/23/2023] [Indexed: 07/20/2023] Open
Abstract
Background/Aim This study aimed to investigate the effects of oxygen therapy using a high flow nasal cannula (HFNC) on patients diagnosed with COVID-19 Acute Respiratory Distress Syndrome (C-ARDS) by utilizing electrical impedance tomography (EIT)-based parameters. Materials and Methods Oxygen therapy was administered to the patients at two different flow rates and two different positions: T0-baseline measurements were taken in the supine position before any therapy was initiated. T1-HFNC was administered in the supine position with a flow rate of 30 L/min. T2-HFNC was administered in the supine position with a flow rate of 50 L/min. T3-HFNC was administered in the prone position with a flow rate of 30 L/min. T4-HFNC was administered in the prone position with a flow rate of 50 L/min. EIT-based parameters (global inhomogeneity index (GI index), center of ventilation (CoV), regional ventilation delay index (RVD index), region of interest ratio (ROI ratio)), as well as respiratory and hemodynamic parameters of the patients, were recorded from the database. Results A total of twenty patients were included in this retrospective observational study. The mean age of the included patients was 64.3 ± 10.6 years. Statistically significant differences were observed in the measurements of GI index, CoV, RVD index, ROI ratio, PaO2/FiO2 ratio, respiratory rate, and mean arterial pressure parameters across different time intervals (p < 0.005). Pairwise comparisons of EIT parameters and measurements of respiratory and hemodynamic parameters at five different time points revealed statistically significant differences. For the GI index, significant differences were observed between the mean measurements taken at T0-T1, T0-T2, T0-T3, T0-T4, T1-T3, T1-T4, T2-T3, T2-T4, and T3-T4 time intervals (p < 0.05). Regarding CoV, significant differences were found between the mean measurements taken at T0-T3, T1-T3, T2-T3, and T3-T4 time intervals (p < 0.05). Additionally, for the ROI ratio, significant differences were observed between the measurement averages taken at each time interval (p < 0.05). Conclusion Our findings suggest that prone positioning during the management of C-ARDS patients leads to improved lung homogeneity, as indicated by EIT parameters. However, further research is required to enhance the visualization of ventilation using EIT.
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Affiliation(s)
- Özlem Öner
- Faculty of Medicine Department of Anesthesiology and Reanimation, Subdivision of Critical Care Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Begum Ergan
- University Faculty of Medicine Department of Pulmonary, Subdivision of Critical Care, Dokuz Eylül University, İzmir, Turkey
| | - Ayse Sezin Kizil
- Faculty of Medicine Department of Anesthesiology and Reanimation, Subdivision of Critical Care Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Mehmet Cagatay Gurkok
- Faculty of Medicine Department of General Surgery, Subdivision of Critical Care Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Esra Dugral
- Pulmonologist and Physiology Specialist, İzmir Katip Çelebi Research and Training Hospital, İzmir, Turkey
| | - Necati Gökmen
- Faculty of Medicine Department of Anesthesiology and Reanimation, Subdivision of Critical Care Medicine, Dokuz Eylül University, İzmir, Turkey
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15
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Rixen J, Eliasson B, Lyra S, Leonhardt S. Shape analysis of training data for neural networks in Electrical Impedance Tomography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38082893 DOI: 10.1109/embc40787.2023.10340254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Electrical Impedance Tomography (EIT) is a cost-effective and fast way to visualize dielectric properties of the human body, through the injection of alternating currents and measurement of the resulting potential on the bodies surface. However, this comes at the cost of low resolution as EIT is a non-linear ill-posed inverse problem. Recently Deep Learning methods have gained the interest in this field, as they provide a way to mimic non-linear functions. Most of the approaches focus on the structure of the Artificial Neural Networks (ANNs), while only glancing over the used training data. However, the structure of the training data is of great importance, as it needs to be simulated. In this work, we analyze the effect of basic shapes to be included as targets in the training data set. We compared inclusions of ellipsoids, cubes and octahedra as training data for ANNs in terms of reconstruction quality. For that, we used the well-established GREIT figures of merit on laboratory tank measurements. We found that ellipsoids resulted in the best reconstruction quality of EIT images. This shows that the choice of simulation data has an impact on the ANN reconstruction quality.Clinical relevance- This work helps to improve time independent EIT reconstruction, which in turn allows for extraction of time independent features of e.g., the lung.
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16
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Dang TH, Jang GY, Lee K, Oh TI. Motion Artifacts Reduction for Noninvasive Hemodynamic Monitoring of Conscious Patients Using Electrical Impedance Tomography: A Preliminary Study. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23115308. [PMID: 37300035 DOI: 10.3390/s23115308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/19/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Electrical impedance tomography (EIT) can monitor the real-time hemodynamic state of a conscious and spontaneously breathing patient noninvasively. However, cardiac volume signal (CVS) extracted from EIT images has a small amplitude and is sensitive to motion artifacts (MAs). This study aimed to develop a new algorithm to reduce MAs from the CVS for more accurate heart rate (HR) and cardiac output (CO) monitoring in patients undergoing hemodialysis based on the source consistency between the electrocardiogram (ECG) and the CVS of heartbeats. Two signals were measured at different locations on the body through independent instruments and electrodes, but the frequency and phase were matched when no MAs occurred. A total of 36 measurements with 113 one-hour sub-datasets were collected from 14 patients. As the number of motions per hour (MI) increased over 30, the proposed algorithm had a correlation of 0.83 and a precision of 1.65 beats per minute (BPM) compared to the conventional statical algorithm of a correlation of 0.56 and a precision of 4.04 BPM. For CO monitoring, the precision and upper limit of the mean ∆CO were 3.41 and 2.82 L per minute (LPM), respectively, compared to 4.05 and 3.82 LPM for the statistical algorithm. The developed algorithm could reduce MAs and improve HR/CO monitoring accuracy and reliability by at least two times, particularly in high-motion environments.
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Affiliation(s)
- Thi Hang Dang
- Department of Medical Engineering, Graduate School, Kyung Hee University, Seoul 02453, Republic of Korea
| | - Geuk Young Jang
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Bundang Hospital, Seongnam-si 13620, Republic of Korea
| | - Kyounghun Lee
- Medical Science Research Institute, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea
| | - Tong In Oh
- Department of Medical Engineering, Graduate School, Kyung Hee University, Seoul 02453, Republic of Korea
- Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul 02453, Republic of Korea
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17
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Liu F, Zhang W, Zhao Z, Xu X, Jian M, Han R. Effect of driving pressure on early postoperative lung gas distribution in supratentorial craniotomy: a randomized controlled trial. BMC Anesthesiol 2023; 23:176. [PMID: 37217882 DOI: 10.1186/s12871-023-02144-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 05/17/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Neurosurgical patients represent a high-risk population for postoperative pulmonary complications (PPCs). A lower intraoperative driving pressure (DP) is related to a reduction in postoperative pulmonary complications. We hypothesized that driving pressure-guided ventilation during supratentorial craniotomy might lead to a more homogeneous gas distribution in the lung postoperatively. METHODS This was a randomized trial conducted between June 2020 and July 2021 at Beijing Tiantan Hospital. Fifty-three patients undergoing supratentorial craniotomy were randomly divided into the titration group or control group at a ratio of 1 to 1. The control group received 5 cmH2O PEEP, and the titration group received individualized PEEP targeting the lowest DP. The primary outcome was the global inhomogeneity index (GI) immediately after extubation obtained by electrical impedance tomography (EIT). The secondary outcomes were lung ultrasonography scores (LUSs), respiratory system compliance, the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) and PPCs within 3 days postoperatively. RESULTS Fifty-one patients were included in the analysis. The median (IQR [range]) DP in the titration group versus the control group was 10 (9-12 [7-13]) cmH2O vs. 11 (10-12 [7-13]) cmH2O, respectively (P = 0.040). The GI tract did not differ between groups immediately after extubation (P = 0.080). The LUSS was significantly lower in the titration group than in the control group immediately after tracheal extubation (1 [0-3] vs. 3 [1-6], P = 0.045). The compliance in the titration group was higher than that in the control group at 1 h after intubation (48 [42-54] vs. 41 [37-46] ml·cmH2O-1, P = 0.011) and at the end of surgery (46 [42-51] vs. 41 [37-44] ml·cmH2O-1, P = 0.029). The PaO2/FiO2 ratio was not significantly different between groups in terms of the ventilation protocol (P = 0.117). At the 3-day follow-up, no postoperative pulmonary complications occurred in either group. CONCLUSIONS Driving pressure-guided ventilation during supratentorial craniotomy did not contribute to postoperative homogeneous aeration, but it may lead to improved respiratory compliance and lower lung ultrasonography scores. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov NCT04421976.
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Affiliation(s)
- Feifei Liu
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, Southwest 4th Ring Road, Fengtai District, Beijing, 100070, China
- Department of Anesthesiology, Beijing Fangshan Liangxiang Hospital, Beijing, China
| | - Wei Zhang
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, Southwest 4th Ring Road, Fengtai District, Beijing, 100070, China
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Xin Xu
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, Southwest 4th Ring Road, Fengtai District, Beijing, 100070, China
| | - Minyu Jian
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, Southwest 4th Ring Road, Fengtai District, Beijing, 100070, China
| | - Ruquan Han
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, Southwest 4th Ring Road, Fengtai District, Beijing, 100070, China.
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18
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Muders T, Hentze B, Leonhardt S, Putensen C. Evaluation of Different Contrast Agents for Regional Lung Perfusion Measurement Using Electrical Impedance Tomography: An Experimental Pilot Study. J Clin Med 2023; 12:jcm12082751. [PMID: 37109088 PMCID: PMC10143707 DOI: 10.3390/jcm12082751] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/22/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Monitoring regional blood flow distribution in the lungs appears to be useful for individually optimizing ventilation therapy. Electrical impedance tomography (EIT) can be used at the bedside for indicator-based regional lung perfusion measurement. Hypertonic saline is widely used as a contrast agent but could be problematic for clinical use due to potential side effects. In five ventilated healthy pigs, we investigated the suitability of five different injectable and clinically approved solutions as contrast agents for EIT-based lung perfusion measurement. Signal extraction success rate, signal strength, and image quality were analyzed after repeated 10 mL bolus injections during temporary apnea. The best results were obtained using NaCl 5.85% and sodium-bicarbonate 8.4% with optimal success rates (100%, each), the highest signal strengths (100 ± 25% and 64 ± 17%), and image qualities (r = 0.98 ± 0.02 and 0.95 ± 0.07). Iomeprol 400 mg/mL (non-ionic iodinated X-ray contrast medium) and Glucose 5% (non-ionic glucose solution) resulted in mostly well usable signals with above average success rates (87% and 89%), acceptable signal strength (32 ± 8% and 16 + 3%), and sufficient image qualities (r = 0.80 ± 0.19 and 0.72 ± 0.21). Isotonic balanced crystalloid solution failed due to a poor success rate (42%), low signal strength (10 ± 4%), and image quality (r = 0.43 ± 0.28). While Iomeprol might enable simultaneous EIT and X-ray measurements, glucose might help to avoid sodium and chloride overload. Further research should address optimal doses to balance reliability and potential side effects.
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Affiliation(s)
- Thomas Muders
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany
| | - Benjamin Hentze
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany
- Chair for Medical Information Technology, RWTH Aachen University, 52074 Aachen, Germany
| | - Steffen Leonhardt
- Chair for Medical Information Technology, RWTH Aachen University, 52074 Aachen, Germany
| | - Christian Putensen
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany
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Aggas JR, Abasi S, Ton C, Salehi S, Liu R, Brandacher G, Grayson WL, Guiseppi-Elie A. Real-Time Monitoring Using Multiplexed Multi-Electrode Bioelectrical Impedance Spectroscopy for the Stratification of Vascularized Composite Allografts: A Perspective on Predictive Analytics. Bioengineering (Basel) 2023; 10:bioengineering10040434. [PMID: 37106621 PMCID: PMC10135882 DOI: 10.3390/bioengineering10040434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/20/2023] [Accepted: 03/24/2023] [Indexed: 04/29/2023] Open
Abstract
Vascularized composite allotransplantation addresses injuries to complex anatomical structures such as the face, hand, and abdominal wall. Prolonged static cold storage of vascularized composite allografts (VCA) incurs damage and imposes transportation limits to their viability and availability. Tissue ischemia, the major clinical indication, is strongly correlated with negative transplantation outcomes. Machine perfusion and normothermia can extend preservation times. This perspective introduces multiplexed multi-electrode bioimpedance spectroscopy (MMBIS), an established bioanalytical method to quantify the interaction of the electrical current with tissue components, capable of measuring tissue edema, as a quantitative, noninvasive, real-time, continuous monitoring technique to provide crucially needed assessment of graft preservation efficacy and viability. MMBIS must be developed, and appropriate models explored to address the highly complex multi-tissue structures and time-temperature changes of VCA. Combined with artificial intelligence (AI), MMBIS can serve to stratify allografts for improvement in transplantation outcomes.
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Affiliation(s)
- John R Aggas
- Bioelectronics, Biosensors and Biochips (C3B®), Department of Biomedical Engineering, Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
- Test Development, Roche Diagnostics, 9115 Hague Road, Indianapolis, IN 46256, USA
| | - Sara Abasi
- Bioelectronics, Biosensors and Biochips (C3B®), Department of Biomedical Engineering, Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
- Media and Metabolism, Wildtype, Inc., 2325 3rd St., San Francisco, CA 94107, USA
| | - Carolyn Ton
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Sara Salehi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Renee Liu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Gerald Brandacher
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
- Department of Plastic & Reconstructive Surgery, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Warren L Grayson
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD 21231, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anthony Guiseppi-Elie
- Bioelectronics, Biosensors and Biochips (C3B®), Department of Biomedical Engineering, Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA
- Department of Cardiovascular Sciences, Houston Methodist Institute for Academic Medicine and Houston Methodist Research Institute, 6670 Bertner Ave., Houston, TX 77030, USA
- ABTECH Scientific, Inc., Biotechnology Research Park, 800 East Leigh Street, Richmond, VA 23219, USA
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20
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Becker S, Schnitzler R, Rembecki M, Geppert J, Kurz CT, Wichelhaus LM, Timmesfeld N, Zahn PK. Individualized flow-controlled versus conventional pressure-controlled ventilation in on-pump heart surgery (FLOWVENTIN HEARTSURG): study protocol for a randomized controlled trial. Trials 2023; 24:195. [PMID: 36922825 PMCID: PMC10018968 DOI: 10.1186/s13063-023-07201-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/22/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND In on-pump cardiac surgery, lungs are at high risk of periprocedural organ impairment because of atelectasis formation, ventilator-induced lung injury, and hyperinflammation due to the cardiopulmonary bypass which results in postoperative pulmonary complications in half of this patient population. The new ventilation mode flow-controlled ventilation (FCV) uniquely allows full control of ins- and expiratory airway flows. This approach reduces the mechanical power of invasive ventilation as a possible cause of ventilator-induced lung injury. The scope of FLOWVENTIN HEARTSURG is to compare perioperative individualized FCV with best clinical practice pressure-controlled ventilation (PVC) modes in patients with elective on-pump cardiac surgery procedures. We hypothesize that the postoperative inflammatory response can be reduced by the perioperative application of FCV compared to PCV. METHODS FLOWVENTIN HEARTSURG is a single-center, randomized, parallel-group trial with two intervention arms: perioperative PCV modes (n = 70, PCV group) with an individualized positive end-expiratory pressure (PEEP) and a tidal volume of 6-8 ml/kg predicted bodyweight compared to perioperative FCV (n = 70, FCV group) with an individualized PEEP and driving pressure, resulting in a liberal tidal volume. As the primary study endpoint interleukin 8 plasma level is assessed 6 h after cardiopulmonary bypass as a surrogate biomarker of systemic and pulmonary inflammation. As secondary aims clinically relevant patient outcomes are analyzed, e.g., perioperative lung function regarding oxygenation indices, postoperative pulmonary and extra-pulmonary complications, SIRS-free days as well as ICU and total inpatient stays. As additional sub-studies with an exploratory approach perioperative right ventricular function parameters are assessed by echocardiography and perioperative lung aeration by electrical impedance tomography. DISCUSSION Current paradigms regarding protective low tidal volume ventilation are consciously left in the FCV intervention group in order to reduce mechanical power as a determinant of ventilator-induced lung injury in this high-risk patient population and procedures. This approach will be compared in a randomized controlled trial with current best clinical practice PCV in FLOWVENTIN HEARTSURG. TRIAL REGISTRATION German Clinical Trials Register DRKS00018956 . Registered on 12 June 2020 (Version 1), last update on 22 August 2022 (Version 4).
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Affiliation(s)
- Simon Becker
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany.
| | - Romina Schnitzler
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
| | - Martin Rembecki
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
| | - Johannes Geppert
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
| | - Christian T Kurz
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
| | - Lisa-Marie Wichelhaus
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
| | - Nina Timmesfeld
- Department of Medical Informatics, Biometry & Epidemiology, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Peter K Zahn
- Department of Anesthesiology, Intensive Care and Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle de La Camp-Platz 1, 44789, Bochum, Germany
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Min Hyun C, Jun Jang T, Nam J, Kwon H, Jeon K, Lee K. Machine learning-based signal quality assessment for cardiac volume monitoring in electrical impedance tomography. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2023. [DOI: 10.1088/2632-2153/acc637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023] Open
Abstract
Abstract
Owing to recent advances in thoracic electrical impedance tomography (EIT), a patient’s hemodynamic function can be noninvasively and continuously estimated in real-time by surveilling a cardiac volume signal (CVS) associated with stroke volume and cardiac output. In clinical applications, however, a CVS is often of low quality, mainly because of the patient’s deliberate movements or inevitable motions during clinical interventions. This study aims to develop a signal quality indexing method that assesses the influence of motion artifacts on transient CVSs. The assessment is performed on each cardiac cycle to take advantage of the periodicity and regularity in cardiac volume changes. Time intervals are identified using the synchronized electrocardiography system. We apply divergent machine-learning methods, which can be sorted into discriminative-model and manifold-learning approaches. The use of machine-learning could be suitable for our real-time monitoring application that requires fast inference and automation as well as high accuracy. In the clinical environment, the proposed method can be utilized to provide immediate warnings so that clinicians can minimize confusion regarding patients’ conditions, reduce clinical resource utilization, and improve the confidence level of the monitoring system. Numerous experiments using actual EIT data validate the capability of CVSs degraded by motion artifacts to be accurately and automatically assessed in real-time by machine learning. The best model achieved an accuracy of 0.95, positive and negative predictive values of 0.96 and 0.86, sensitivity of 0.98, specificity of 0.77, and AUC of 0.96.
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22
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Real-Time Measurements of Relative Tidal Volume and Stroke Volume Using Electrical Impedance Tomography with Spatial Filters: A Feasibility Study in a Swine Model Under Normal and Reduced Ventilation. Ann Biomed Eng 2023; 51:394-409. [PMID: 35960417 DOI: 10.1007/s10439-022-03040-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 07/28/2022] [Indexed: 01/25/2023]
Abstract
Continuous monitoring of both hemodynamic and respiratory parameters would be beneficial to patients, e.g., those in intensive care unit. The objective of this exploratory animal study was to test the feasibility of simultaneous measurements of relative tidal volume (rTV) and relative stroke volume (rSV) using an electrical impedance tomography (EIT) device equipped with a new real-time source separation algorithm implemented as two spatial filters. Five pigs were anesthetized and mechanically ventilated. The supplied tidal volume from a mechanical ventilator was reduced to 70, 50 and 30% from the 100% normal volume to simulate hypoventilation. The respiratory volume signal and cardiac volume signal were generated by applying the spatial filters to the acquired EIT data, from which values of rTV and rSV were extracted. The measured rTV values were compared with the TV values from the mechanical ventilator using the four-quadrant concordance analysis method. For changes in TV, the concordance rate in each animal ranged from 81.8% to 100%, while it was 92.5% when the data from all five animals were pooled together. When the measured rTV values for each animal were scaled to the absolute TVEIT values in mL using the TVVent data from the mechanical ventilator, the smallest 95% limits of agreement (LoA) were - 6.04 and 7.44 mL for the 70% ventilation level, and the largest 95% LoA were - 18.1 and 19.4 mL for the 50% ventilation level. The percentage error between TVEIT and TVVent was 10.3%. Although similar statistical analyses on rSV data could not be performed due to limited intra-animal variability, changes in rSV values measured by the EIT device were comparable to those measured by an invasive hemodynamic monitor. In this animal study, we were able to demonstrate the feasibility of an EIT device for noninvasive and simultaneous measurements of rTV and rSV in real time. However, the performance of the real-time source separation method needs to be further validated on animals and human subjects, particularly over a wide range of SV values. Future clinical studies are needed to assess the potential usefulness of the new method in dynamic cardiopulmonary monitoring and explore other clinical applications.
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Hu CL, Lin ZY, Hu SY, Cheng IC, Huang CH, Li YH, Li CJ, Lin CW. Compensation for Electrode Detachment in Electrical Impedance Tomography with Wearable Textile Electrodes. SENSORS (BASEL, SWITZERLAND) 2022; 22:9575. [PMID: 36559943 PMCID: PMC9782024 DOI: 10.3390/s22249575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Electrical impedance tomography (EIT) is a radiation-free and noninvasive medical image reconstruction technique in which a current is injected and the reflected voltage is received through electrodes. EIT electrodes require good connection with the skin for data acquisition and image reconstruction. However, detached electrodes are a common occurrence and cause measurement errors in EIT clinical applications. To address these issues, in this study, we proposed a method for detecting faulty electrodes using the differential voltage value of the detached electrode in an EIT system. Additionally, we proposed the voltage-replace and voltage-shift methods to compensate for invalid data from the faulty electrodes. In this study, we present the simulation, experimental, and in vivo chest results of our proposed methods to verify and evaluate the feasibility of this approach.
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Affiliation(s)
- Chang-Lin Hu
- Industrial Technology Research Institute, Hsinchu 310, Taiwan
| | - Zong-Yan Lin
- Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan
| | - Shu-Yun Hu
- College of Law, National University of Kaohsiung, Kaohsiung 811, Taiwan
| | - I-Cheng Cheng
- Industrial Technology Research Institute, Hsinchu 310, Taiwan
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Chih-Hsien Huang
- Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Yu-Hao Li
- Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Chien-Ju Li
- Industrial Technology Research Institute, Hsinchu 310, Taiwan
| | - Chii-Wann Lin
- Industrial Technology Research Institute, Hsinchu 310, Taiwan
- Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan
- Department of Biomedical Engineering, National Taiwan University, Taipei 106, Taiwan
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Ellenberger C, Pelosi P, de Abreu MG, Wrigge H, Diaper J, Hagerman A, Adam Y, Schultz MJ, Licker M. Distribution of ventilation and oxygenation in surgical obese patients ventilated with high versus low positive end-expiratory pressure: A substudy of a randomised controlled trial. Eur J Anaesthesiol 2022; 39:875-884. [PMID: 36093886 PMCID: PMC9553219 DOI: 10.1097/eja.0000000000001741] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND Intra-operative ventilation using low/physiological tidal volume and positive end-expiratory pressure (PEEP) with periodic alveolar recruitment manoeuvres (ARMs) is recommended in obese surgery patients. OBJECTIVES To investigate the effects of PEEP levels and ARMs on ventilation distribution, oxygenation, haemodynamic parameters and cerebral oximetry. DESIGN A substudy of a randomised controlled trial. SETTING Tertiary medical centre in Geneva, Switzerland, between 2015 and 2018. PATIENTS One hundred and sixty-two patients with a BMI at least 35 kg per square metre undergoing elective open or laparoscopic surgery lasting at least 120 min. INTERVENTION Patients were randomised to PEEP of 4 cmH 2 O ( n = 79) or PEEP of 12 cmH 2 O with hourly ARMs ( n = 83). MAIN OUTCOME MEASURES The primary endpoint was the fraction of ventilation in the dependent lung as measured by electrical impedance tomography. Secondary endpoints were the oxygen saturation index (SaO 2 /FIO 2 ratio), respiratory and haemodynamic parameters, and cerebral tissue oximetry. RESULTS Compared with low PEEP, high PEEP was associated with smaller intra-operative decreases in dependent lung ventilation [-11.2%; 95% confidence interval (CI) -8.7 to -13.7 vs. -13.9%; 95% CI -11.7 to -16.5; P = 0.029], oxygen saturation index (-49.6%; 95% CI -48.0 to -51.3 vs. -51.3%; 95% CI -49.6 to -53.1; P < 0.001) and a lower driving pressure (-6.3 cmH 2 O; 95% CI -5.7 to -7.0). Haemodynamic parameters did not differ between the groups, except at the end of ARMs when arterial pressure and cardiac index decreased on average by -13.7 mmHg (95% CI -12.5 to -14.9) and by -0.54 l min -1 m -2 (95% CI -0.49 to -0.59) along with increased cerebral tissue oximetry (3.0 and 3.2% on left and right front brain, respectively). CONCLUSION In obese patients undergoing abdominal surgery, intra-operative PEEP of 12 cmH 2 O with periodic ARMs, compared with intra-operative PEEP of 4 cmH 2 O without ARMs, slightly redistributed ventilation to dependent lung zones with minor improvements in peripheral and cerebral oxygenation. TRIAL REGISTRATION NCT02148692, https://clinicaltrials.gov/ct2.
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Affiliation(s)
- Christoph Ellenberger
- From the Department of Anaesthesia, Pharmacology, Intensive Care and Emergency Medicine, University Hospital of Geneva, rue Gabriel-Perret-Gentil (CE, JD, AH, YA, ML), Faculty of Medicine, University of Geneva, Geneva, Switzerland (CE, ML), Department of Surgical Sciences and Integrated Diagnostics, University of Genoa (PP), Anaesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy (PP), Pulmonary Engineering Group, Department of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Dresden, Germany (MGdA), Department of Outcomes Research (MGdA), Department of Intensive Care and Resuscitation, Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, USA (MGdA), Department of Anaesthesiology, Intensive Care and Emergency Medicine, Pain Therapy, Bergmannstrost Hospital (HW), Medical Faculty, Martin-Luther-University Halle-Wittenberg, Halle, Germany (HW), Department of Intensive Care & Laboratory of Experimental Intensive Care and Anesthesiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands (MJS)
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25
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Yu M, Deng Y, Cha J, Jiang L, Wang M, Qiao S, Wang C. PEEP titration by EIT strategies for patients with ARDS: A systematic review and meta-analysis. Med Intensiva 2022:S2173-5727(22)00207-7. [PMID: 36243630 DOI: 10.1016/j.medine.2022.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/04/2022] [Accepted: 06/20/2022] [Indexed: 06/16/2023]
Abstract
OBJECTIVE To determine which method of Positive End-expiratory Pressure (PEEP) titration is more useful, and to establish an evidence base for the clinical impact of Electrical Impedance Tomography (EIT) based individual PEEP setting which appears to be a promising method to optimize PEEP in Acute Respiratory Distress Syndrome (ARDS) patients. DESIGN A systematic review and meta-analysis. SETTING 4 databases (PUBMED, EMBASE, Web Of Science, and the Cochrane Library) from 1980 to December 2020 were performed. PARTICIPANTS Randomized clinical trials patients with ARDS. MAIN VARIABLES PaO2/FiO2-ratio and respiratory system compliance. INTERVENSION The quality of the studies was assessed with the Cochrane risk and bias tool. RESULTS 8 trials, including a total of 222 participants, were eligible for analysis. Meta-analysis demonstrates a significantly EIT-based individual PEEP setting for patients receiving higher PaO2/FiO2 ratio as compared to other PEEP titration strategies [5 trials, 202 patients, SMD 0.636, (95% CI 0.364-0.908)]. EIT-drived PEEP titration strategy did not significantly increase respiratory system compliance when compared to other peep titration strategies, [7 trials, 202 patients, SMD -0.085, (95% CI -0.342 to 0.172)]. CONCLUSIONS The benefits of PEEP titration with EIT on clinical outcomes of ARDS in placebo-controlled trials probably result from the visible regional ventilation of EIT. These findings offer clinicians and stakeholders a comprehensive assessment and high-quality evidence for the safety and efficacy of the EIT-based individual PEEP setting as a superior option for patients who undergo ARDS.
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Affiliation(s)
- Mengnan Yu
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Yanjun Deng
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China; Department of Intensive Care Unit, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Jun Cha
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Lingyan Jiang
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Mingdeng Wang
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China; Department of Intensive Care Unit, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Shigang Qiao
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China; Institute of Clinical Medicine Research, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China
| | - Chen Wang
- Faculty of Anesthesiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China; Institute of Clinical Medicine Research, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, Jiangsu Province, China.
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Brabant O, Loroesch S, Adler A, Waldmann AD, Raisis A, Mosing M. Performance evaluation of electrode design and material for a large animal electrical impedance tomography belt. Vet Rec 2022; 191:e2184. [PMID: 36197754 DOI: 10.1002/vetr.2184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/14/2022] [Accepted: 08/08/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) produces lung ventilation images via a thoracic electrode belt. Robust electrode design and material, providing low electrode skin contact impedance (SCI), is needed in veterinary medicine. The aim of this study was to compare three EIT electrode designs and materials. METHODS Simulations of cylindrical, rectangular and spiked electrode designs were used to evaluate electrode SCI as a function of electrode size, where skin contact was uneven. Gold-plated washers (EGW ), zinc-plated rivets (EZR ) and zinc-galvanised spikes (EZS ) were assigned randomly on two interconnected EIT belts. Gel was applied to the cranial or caudal belt and placed on 17 standing cattle. SCI was recorded at baseline and 3, 5, 7, 9 and 11 minutes later. RESULTS Simulations that involved electrodes with a greater skin contact area had lower and more uniform SCI. In cattle, SCI decreased with all electrodes over time (p < 0.01). Without gel, no difference was found between EGW and EZS , while SCI was higher for EZR (p < 0.03). With gel, SCI was lower in EGW and EZR (p < 0.026), with the SCI in EGW being the lowest (p < 0.01). LIMITATIONS Low numbers of animals and static electrode position may affect SCI. CONCLUSIONS Electrode design is important for EIT measurement, with larger electrode designs able to compensate for the use of less conductive materials. Gel is not necessary to achieve acceptable SCI in large animals.
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Affiliation(s)
- Olivia Brabant
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Sarah Loroesch
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | - Andreas D Waldmann
- Department of Anaesthesiology and Intensive Care Medicine, Rostock University Medical Centre, Rostock, Germany
| | - Anthea Raisis
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Martina Mosing
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
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Electrical Impedance Tomography Can Be Used to Quantify Lung Hyperinflation during HFOV: The Pilot Study in Pigs. Diagnostics (Basel) 2022; 12:diagnostics12092081. [PMID: 36140483 PMCID: PMC9497761 DOI: 10.3390/diagnostics12092081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Dynamic hyperinflation is reported as a potential risk during high-frequency oscillatory ventilation (HFOV), and its existence has been documented both by physical models and by CT. The aim of this study is to determine the suitability of electrical impendence tomography (EIT) for the measurement of dynamic lung hyperinflation and hypoinflation during HFOV. Eleven healthy pigs were anaesthetized and ventilated using HFOV. The difference between the airway pressure at the airway opening and alveolar space was measured by EIT and esophageal balloons at three mean airway pressures (12, 18 and 24 cm H2O) and two inspiratory to expiratory time ratios (1:1, 1:2). The I:E ratio was the primary parameter associated with differences between airway and alveolar pressures. All animals showed hyperinflation at a 1:1 ratio (median 1.9 cm H2O) and hypoinflation at a 1:2 (median –4.0 cm H2O) as measured by EIT. EIT measurements had a linear correlation to esophageal balloon measurements (r2 = –0.915, p = 0.0085). EIT measurements were slightly higher than that of the esophageal balloon transducer with the mean difference of 0.57 cm H2O. Presence of a hyperinflation or hypoinflation was also confirmed independently by chest X-ray. We found that dynamic hyperinflation developed during HFOV may be detected and characterized noninvasively by EIT.
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A Rapid, Low-Cost, and High-Precision Multifrequency Electrical Impedance Tomography Data Acquisition System for Plant Phenotyping. REMOTE SENSING 2022. [DOI: 10.3390/rs14133214] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Plant phenotyping plays an important role for the thorough assessment of plant traits such as growth, development, and physiological processes with the target of achieving higher crop yields by the proper crop management. The assessment can be done by utilizing two- and three-dimensional image reconstructions of the inhomogeneities. The quality of the reconstructed image is required to maintain a high accuracy and a good resolution, and it is desirable to reconstruct the images with the lowest possible noise. In this work, an electrical impedance tomography (EIT) data acquisition system is developed for the reconstruction and evaluation of the inhomogeneities by utilizing a non-destructive method. A high-precision EIT system is developed by designing an electrode array sensor using a cylindrical domain for the measurements in different planes. Different edible plant slices along with multiple plant roots are taken in the EIT domain to assess and calibrate the system, and their reconstructed results are evaluated by utilizing an impedance imaging technique. A non-invasive imaging is carried out in multiple frequencies by utilizing a difference method of reconstruction. The performance and accuracy of the EIT system are evaluated by measuring impedances between 1 and 100 kHz using a low-cost and rapid electrical impedance spectroscopy (EIS) tool connected to the sensor. A finite element method (FEM) modeling is utilized for image reconstruction, which is carried out using electrical impedance and diffuse optical tomography reconstruction software (EIDORS). The reconstruction is made successfully with the optimized results obtained using Gauss–Newton (GN) algorithms.
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An In Situ Electrical Impedance Tomography Sensor System for Biomass Estimation of Tap Roots. PLANTS 2022; 11:plants11131713. [PMID: 35807666 PMCID: PMC9269135 DOI: 10.3390/plants11131713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 12/02/2022]
Abstract
Root biomass is one of the most relevant root parameters for studies of plant response to environmental change. In this work, a dynamic and adjustable electrode array sensor system is designed for developing a cost-effective, high-speed data acquisition system based on electrical impedance tomography (EIT). The developed EIT system is found to be suitable for in situ measurements and capable of monitoring the changes in root growth and development with three-dimensional imaging by measuring impedances in multiple frequencies with the help of an EIT sensor. The designed EIT sensor system is assessed and calibrated by the inhomogeneities in both water and soil media. The impedances are measured for multiple tap roots using an electrical impedance spectroscopy (EIS) tool connected to the sensor at frequencies ranging from 1 kHz to 100 kHz. The changes in conductivity are calculated by obtaining the boundary voltages from the measured impedances for a given stimulation current. A non-invasive imaging method is utilized, and the spectral changes are observed accordingly to evaluate the growth of the roots. A further root analysis helps us estimate the root biomass non-destructively in real-time. The root size (such as, weight, length) is correlated with the measured impedances. A regression analysis is performed using the least square method, and more than 97% correlation is found for the biomass estimation of carrot roots with an RMSE of 4.516. The obtained models are later validated using a new and separate set of carrot root samples and the accuracy of the predicted models is found to be 93% or above. A complete electrode model is utilized, and the reconstruction analysis is performed and optimized by utilizing the impedance imaging technique in difference method. The tomography of the root is reconstructed with finite element method (FEM) modeling considering one-step Gauss–Newton (GN) algorithm which is carried out using an open source software known as electrical impedance and diffuse optical tomography reconstruction software (EIDORS).
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Rauseo M, Spinelli E, Sella N, Slobod D, Spadaro S, Longhini F, Giarratano A, Gilda C, Mauri T, Navalesi P. Expert opinion document: "Electrical impedance tomography: applications from the intensive care unit and beyond". JOURNAL OF ANESTHESIA, ANALGESIA AND CRITICAL CARE (ONLINE) 2022; 2:28. [PMID: 37386674 DOI: 10.1186/s44158-022-00055-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/01/2022] [Indexed: 07/01/2023]
Abstract
Mechanical ventilation is a life-saving technology, but it can also inadvertently induce lung injury and increase morbidity and mortality. Currently, there is no easy method of assessing the impact that ventilator settings have on the degree of lung inssflation. Computed tomography (CT), the gold standard for visually monitoring lung function, can provide detailed regional information of the lung. Unfortunately, it necessitates moving critically ill patients to a special diagnostic room and involves exposure to radiation. A technique introduced in the 1980s, electrical impedance tomography (EIT) can non-invasively provide similar monitoring of lung function. However, while CT provides information on the air content, EIT monitors ventilation-related changes of lung volume and changes of end expiratory lung volume (EELV). Over the past several decades, EIT has moved from the research lab to commercially available devices that are used at the bedside. Being complementary to well-established radiological techniques and conventional pulmonary monitoring, EIT can be used to continuously visualize the lung function at the bedside and to instantly assess the effects of therapeutic maneuvers on regional ventilation distribution. EIT provides a means of visualizing the regional distribution of ventilation and changes of lung volume. This ability is particularly useful when therapy changes are intended to achieve a more homogenous gas distribution in mechanically ventilated patients. Besides the unique information provided by EIT, its convenience and safety contribute to the increasing perception expressed by various authors that EIT has the potential to be used as a valuable tool for optimizing PEEP and other ventilator settings, either in the operative room and in the intensive care unit. The effects of various therapeutic interventions and applications on ventilation distribution have already been assessed with the help of EIT, and this document gives an overview of the literature that has been published in this context.
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Affiliation(s)
- Michela Rauseo
- Department of Anesthesia and Intensive Care Medicine, University of Foggia, Policlinico Riuniti di Foggia, Foggia, Italy.
| | - Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda Ospedale Maggiore Policlinico Milan, Milano, Italy
| | - Nicolò Sella
- Instiute of Anesthesia and Intensive Care, Padua University Hospital, Padova, Italy
| | - Douglas Slobod
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda Ospedale Maggiore Policlinico Milan, Milano, Italy
- Department of Critical Care Medicine, McGill University, Montreal, Quebec, Canada
| | - Savino Spadaro
- Anesthesia and Intensive Care Unit, Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | - Federico Longhini
- Anesthesia and Intensive Care Unit, Department of Medical and Surgical Sciences, "Magna Graecia" University, "Mater Domini" University Hospital, Catanzaro, Italy
| | - Antonino Giarratano
- Department of Surgical, Oncological and Oral Science (Di.Chir.On.S.), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Policlinico Paolo Giaccone, University of Palermo, Palermo, Italy
| | - Cinnella Gilda
- Department of Anesthesia and Intensive Care Medicine, University of Foggia, Policlinico Riuniti di Foggia, Foggia, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda Ospedale Maggiore Policlinico Milan, Milano, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Paolo Navalesi
- Instiute of Anesthesia and Intensive Care, Padua University Hospital, Padova, Italy
- Department of Medicine - DIMED, University of Padua, Padova, Italy
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Bounik R, Cardes F, Ulusan H, Modena MM, Hierlemann A. Impedance Imaging of Cells and Tissues: Design and Applications. BME FRONTIERS 2022; 2022:1-21. [PMID: 35761901 PMCID: PMC7612906 DOI: 10.34133/2022/9857485] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 03/28/2022] [Indexed: 11/09/2022] Open
Abstract
Due to their label-free and noninvasive nature, impedance measurements have attracted increasing interest in biological research. Advances in microfabrication and integrated-circuit technology have opened a route to using large-scale microelectrode arrays for real-time, high-spatiotemporal-resolution impedance measurements of biological samples. In this review, we discuss different methods and applications of measuring impedance for cell and tissue analysis with a focus on impedance imaging with microelectrode arrays in in vitro applications. We first introduce how electrode configurations and the frequency range of the impedance analysis determine the information that can be extracted. We then delve into relevant circuit topologies that can be used to implement impedance measurements and their characteristic features, such as resolution and data-acquisition time. Afterwards, we detail design considerations for the implementation of new impedance-imaging devices. We conclude by discussing future fields of application of impedance imaging in biomedical research, in particular applications where optical imaging is not possible, such as monitoring of ex vivo tissue slices or microelectrode-based brain implants.
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Affiliation(s)
- Raziyeh Bounik
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Fernando Cardes
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Hasan Ulusan
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Mario M. Modena
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Andreas Hierlemann
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
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Neelakantan S, Xin Y, Gaver DP, Cereda M, Rizi R, Smith BJ, Avazmohammadi R. Computational lung modelling in respiratory medicine. J R Soc Interface 2022; 19:20220062. [PMID: 35673857 PMCID: PMC9174712 DOI: 10.1098/rsif.2022.0062] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Computational modelling of the lungs is an active field of study that integrates computational advances with lung biophysics, biomechanics, physiology and medical imaging to promote individualized diagnosis, prognosis and therapy evaluation in lung diseases. The complex and hierarchical architecture of the lung offers a rich, but also challenging, research area demanding a cross-scale understanding of lung mechanics and advanced computational tools to effectively model lung biomechanics in both health and disease. Various approaches have been proposed to study different aspects of respiration, ranging from compartmental to discrete micromechanical and continuum representations of the lungs. This article reviews several developments in computational lung modelling and how they are integrated with preclinical and clinical data. We begin with a description of lung anatomy and how different tissue components across multiple length scales affect lung mechanics at the organ level. We then review common physiological and imaging data acquisition methods used to inform modelling efforts. Building on these reviews, we next present a selection of model-based paradigms that integrate data acquisitions with modelling to understand, simulate and predict lung dynamics in health and disease. Finally, we highlight possible future directions where computational modelling can improve our understanding of the structure–function relationship in the lung.
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Affiliation(s)
- Sunder Neelakantan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Yi Xin
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Donald P. Gaver
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim Rizi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Reza Avazmohammadi
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
- Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, TX, USA
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Abstract
OBJECTIVE To describe, through a narrative review, the physiologic principles underlying electrical impedance tomography, and its potential applications in managing acute respiratory distress syndrome (ARDS). To address the current evidence supporting its use in different clinical scenarios along the ARDS management continuum. DATA SOURCES We performed an online search in Pubmed to review articles. We searched MEDLINE, Cochrane Central Register, and clinicaltrials.gov for controlled trials databases. STUDY SELECTION Selected publications included case series, pilot-physiologic studies, observational cohorts, and randomized controlled trials. To describe the rationale underlying physiologic principles, we included experimental studies. DATA EXTRACTION Data from relevant publications were reviewed, analyzed, and its content summarized. DATA SYNTHESIS Electrical impedance tomography is an imaging technique that has aided in understanding the mechanisms underlying multiple interventions used in ARDS management. It has the potential to monitor and predict the response to prone positioning, aid in the dosage of flow rate in high-flow nasal cannula, and guide the titration of positive-end expiratory pressure during invasive mechanical ventilation. The latter has been demonstrated to improve physiologic and mechanical parameters correlating with lung recruitment. Similarly, its use in detecting pneumothorax and harmful patient-ventilator interactions such as pendelluft has been proven effective. Nonetheless, its impact on clinically meaningful outcomes remains to be determined. CONCLUSIONS Electrical impedance tomography is a potential tool for the individualized management of ARDS throughout its different stages. Clinical trials should aim to determine whether a specific approach can improve clinical outcomes in ARDS management.
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Mosing M, Cheong JM, Müller B, Böhm S, Hosgood G, Raisis A. Determination of tidal volume by electrical impedance tomography (EIT) after indirect two-point calibration. Physiol Meas 2022; 43. [PMID: 35322796 DOI: 10.1088/1361-6579/ac604a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/23/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE A linear relationship between impedance change (△Z) measured by thoracic electrical impedance tomography (EIT) and tidal volume (VT) has been demonstrated. This study evaluated the agreement between the displayed VT calculated by the EIT software (VTEIT) and spirometry (VTSPIRO) after an indirect two-point calibration. APPROACH The EIT software was programmed to execute a bedside two-point calibration from the subject-specific, linear equation defining the relationship between △Z and VTSPIROand displaying VTEITbreath-by-breath in 20 neutered male, juvenile pigs. After EIT calibration VTs of 8, 12, 16 and 20 mL kg-1were applied to the lungs. VTEITand VTSPIROwere recorded and analysed using Bland-Altman plot for multiple subject measurements. Volumetric capnography (VCap) and spirometry data were explored as components of variance using multiple regression. MAIN RESULTS A mean relative difference (bias) of 0.7% with 95% confidence interval (CI) of -10.4 - 10.7% were found between VTEITand VTSPIROfor the analysed data set. The variance in VTEITcould not be explained by any of the measured VCap or spirometry variables. SIGNIFICANCE The narrow CI estimated in this study allows the conclusion that EIT and its software can be used to measure and accurately convert △Z into mililitre VT at the bedside after applying an indirect two-point calibration.
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Affiliation(s)
- Martina Mosing
- School of Veterinary and Life Science, Murdoch University, 90 South Street, Perth, 6150, AUSTRALIA
| | | | - Beat Müller
- SenTec AG, Kantonsstrasse 14, Therwil, Basel-Landschaft, 7302, SWITZERLAND
| | - Stephan Böhm
- Rostock University Medical Center, Schillingallee 35, Rostock, Mecklenburg-Vorpommern, 18057, GERMANY
| | - Giselle Hosgood
- Murdoch University, 90 South Street, Murdoch, 6150, AUSTRALIA
| | - Anthea Raisis
- Murdoch University, 90 South Street, Murdoch, 6150, AUSTRALIA
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A Rotational Invariant Neural Network for Electrical Impedance Tomography Imaging without Reference Voltage: RF-REIM-NET. Diagnostics (Basel) 2022; 12:diagnostics12040777. [PMID: 35453825 PMCID: PMC9028444 DOI: 10.3390/diagnostics12040777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/16/2022] [Accepted: 03/19/2022] [Indexed: 02/04/2023] Open
Abstract
Background: Electrical Impedance Tomography (EIT) is a radiation-free technique for image reconstruction. However, as the inverse problem of EIT is non-linear and ill-posed, the reconstruction of sharp conductivity images poses a major problem. With the emergence of artificial neural networks (ANN), their application in EIT has recently gained interest. Methodology: We propose an ANN that can solve the inverse problem without the presence of a reference voltage. At the end of the ANN, we reused the dense layers multiple times, considering that the EIT exhibits rotational symmetries in a circular domain. To avoid bias in training data, the conductivity range used in the simulations was greater than expected in measurements. We also propose a new method that creates new data samples from existing training data. Results: We show that our ANN is more robust with respect to noise compared with the analytical Gauss–Newton approach. The reconstruction results for EIT phantom tank measurements are also clearer, as ringing artefacts are less pronounced. To evaluate the performance of the ANN under real-world conditions, we perform reconstructions on an experimental pig study with computed tomography for comparison. Conclusions: Our proposed ANN can reconstruct EIT images without the need of a reference voltage.
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36
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Electrical impedance tomography in the adult intensive care unit. Curr Opin Crit Care 2022; 28:292-301. [DOI: 10.1097/mcc.0000000000000936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Xu M, He H, Long Y. Lung Perfusion Assessment by Bedside Electrical Impedance Tomography in Critically Ill Patients. Front Physiol 2021; 12:748724. [PMID: 34721072 PMCID: PMC8548642 DOI: 10.3389/fphys.2021.748724] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/13/2021] [Indexed: 12/02/2022] Open
Abstract
As a portable, radiation-free imaging modality, electrical impedance tomography (EIT) technology has shown promise in the bedside visual assessment of lung perfusion distribution in critically ill patients. The two main methods of EIT for assessing lung perfusion are the pulsatility and conductivity contrast (saline) bolus method. Increasing attention is being paid to the saline bolus EIT method in the evaluation of regional pulmonary perfusion in clinical practice. This study seeks to provide an overview of experimental and clinical studies with the aim of clarifying the progress made in the use of the saline bolus EIT method. Animal studies revealed that the saline bolus EIT method presented good consistency with single-photon emission CT (SPECT) in the evaluation of lung regional perfusion changes in various pathological conditions. Moreover, the saline bolus EIT method has been applied to assess the lung perfusion in a pulmonary embolism and the effect of positive end-expiratory pressure (PEEP) on regional ventilation/perfusion ratio (V/Q) and acute respiratory distress syndrome (ARDS) in several clinical studies. The implementation of saline boluses, data analyses, precision, and cutoff values varied among different studies, and a consensus must be reached regarding the clinical application of the saline bolus EIT method. Further study is required to validate the impact of the described saline bolus EIT method on decision-making, therapeutic management, and outcomes in critically ill patients.
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Affiliation(s)
- Mengru Xu
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Critical Care Medicine, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Huaiwu He
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Critical Care Medicine, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Yun Long
- State Key Laboratory of Complex Severe and Rare Diseases, Department of Critical Care Medicine, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
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Ko RE, Jang GY, Chung CR, Lee JY, Oh TI, Suh GY, Kim Y, Woo EJ. Noninvasive Beat-To-Beat Stroke Volume Measurements to Determine Preload Responsiveness During Mini-Fluid Challenge in a Swine Model: A Preliminary Study. Shock 2021; 56:850-856. [PMID: 33534400 DOI: 10.1097/shk.0000000000001739] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT Cardiac output (CO) is an important parameter in fluid management decisions for treating hemodynamically unstable patients in intensive care unit. The gold standard for CO measurements is the thermodilution method, which is an invasive procedure with intermittent results. Recently, electrical impedance tomography (EIT) has emerged as a new method for noninvasive measurements of stroke volume (SV). The objectives of this paper are to compare EIT with an invasive pulse contour analysis (PCA) method in measuring SV during mini-fluid challenge in animals and determine preload responsiveness with EIT. Five pigs were anesthetized and mechanically ventilated. After removing 25% to 30% of the total blood from each animal, multiple fluid injections were conducted. The EIT device successfully tracked changes in SV beat-to-beat during varying volume states, i.e., from hypovolemia and preload responsiveness to target volume and volume overload. From a total of 50 100-mL fluid injections on five pigs (10 injections per pig), the preload responsiveness value was as large as 32.3% in the preload responsiveness state while in the volume overload state it was as low as -4.9%. The bias of the measured SV data using EIT and PCA was 0 mL, and the limits of agreement were ±3.6 mL in the range of 17.6 mL to 51.0 mL. The results of the animal experiments suggested that EIT is capable of measuring beat-to-beat SV changes during mini-fluid challenge and determine preload responsiveness. Further animal and clinical studies will be needed to demonstrate the feasibility of the EIT method as a new tool for fluid management.
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Affiliation(s)
- Ryoung Eun Ko
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Geuk Young Jang
- Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea
| | - Chi Ryang Chung
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jin Young Lee
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Tong In Oh
- Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea
| | - Gee Young Suh
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yongmin Kim
- Department of Creative IT Engineering, POSTECH, Pohang, Korea
| | - Eung Je Woo
- Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea
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A wearable eddy current based pulmonary function sensor for continuous non-contact point-of-care monitoring during the COVID-19 pandemic. Sci Rep 2021; 11:20144. [PMID: 34635738 PMCID: PMC8505507 DOI: 10.1038/s41598-021-99682-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 09/29/2021] [Indexed: 11/10/2022] Open
Abstract
Pulmonary function testing (PFT) allows for quantitative analysis of lung function. However, as a result of the coronavirus disease 2019 (COVID-19) pandemic, a majority of international medical societies have postponed PFTs in an effort to mitigate disease transmission, complicating the continuity of care in high-risk patients diagnosed with COVID-19 or preexisting lung pathologies. Here, we describe the development of a non-contact wearable pulmonary sensor for pulmonary waveform analysis, pulmonary volume quantification, and crude thoracic imaging using the eddy current (EC) phenomenon. Statistical regression analysis is performed to confirm the predictive validity of the sensor, and all data are continuously and digitally stored with a sampling rate of 6,660 samples/second. Wearable pulmonary function sensors may facilitate rapid point-of-care monitoring for high-risk individuals, especially during the COVID-19 pandemic, and easily interface with patient hospital records or telehealth services.
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40
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Shi Y, Yang Z, Xie F, Ren S, Xu S. The Research Progress of Electrical Impedance Tomography for Lung Monitoring. Front Bioeng Biotechnol 2021; 9:726652. [PMID: 34660553 PMCID: PMC8517404 DOI: 10.3389/fbioe.2021.726652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/09/2021] [Indexed: 01/16/2023] Open
Abstract
Medical imaging can intuitively show people the internal structure, morphological information, and organ functions of the organism, which is one of the most important inspection methods in clinical medical diagnosis. Currently used medical imaging methods can only be applied to some diagnostic occasions after qualitative lesions have been generated, and the general imaging technology is usually accompanied by radiation and other conditions. However, electrical impedance tomography has the advantages of being noninvasive and non-radiative. EIT (Electrical Impedance Tomography) is also widely used in the early diagnosis and treatment of some diseases because of these advantages. At present, EIT is relatively mature and more and more image reconstruction algorithms are used to improve imaging resolution. Hardware technology is also developing rapidly, and the accuracy of data collection and processing is continuously improving. In terms of clinical application, EIT has also been used for pathological treatment of lungs, the brain, and the bladder. In the future, EIT has a good application prospect in the medical field, which can meet the needs of real-time, long-term monitoring and early diagnosis. Aiming at the application of EIT in the treatment of lung pathology, this article reviews the research progress of EIT, image reconstruction algorithms, hardware system design, and clinical applications used in the treatment of lung diseases. Through the research and introduction of several core components of EIT technology, it clarifies the characteristics of EIT system complexity and its solutions, provides research ideas for subsequent research, and once again verifies the broad development prospects of EIT technology in the future.
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Affiliation(s)
- Yan Shi
- The School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
| | - ZhiGuo Yang
- The School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
| | - Fei Xie
- Department of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Shuai Ren
- The School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, China
| | - ShaoFeng Xu
- The School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
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41
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Sun B, Darma PN, Shirai T, Narita K, Takei M. Electrical-tomographic imaging of physiological-induced conductive response in calf muscle compartments during voltage intensity change of electrical muscle stimulation ( vic-EMS). Physiol Meas 2021; 42. [PMID: 34467954 DOI: 10.1088/1361-6579/ac2265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/31/2021] [Indexed: 11/12/2022]
Abstract
Objectives. The electrical-tomographic imaging has been achieved for exploring differential tendency of physiological-induced conductive response in calf muscle compartments during voltage intensity change of electrical muscle stimulation (vic-EMS).Approach. In the experiments, the differential tendency of conductivity distribution imagesσduringvic-EMS were clearly imaged as three responsive muscle compartments, which are calledM1compartment composed of gastrocnemius muscle,M2compartment composed of tibialis anterior, extensor digitorum longus, and peroneus longus muscles, andM3compartment composed of soleus muscle.Main results. The differential tendency of spatial-mean conductivity 〈σ〉M1is the same as the differential tendency of venous blood flow velocityvbland blood lactate concentrationCblduringvic-EMS by the increased tendency of spatial-mean conductivity difference Δ〈σ〉M1, venous blood flow velocity difference Δvbland blood lactate concentration difference ΔCbl. The 〈σ〉M1is increased with the increase of voltage intensity from 〈σpre〉M1 = 0.142 [-] to 〈σl14 〉 M1 = 0.442 [-] (pre: pre-training,l14: voltage level duringvic-EMSl = 14) by Δ〈σl14-pre〉M1 = 204.2% (n = 16,p < 0.01). Correspondingly, thevblandCblare increased with the increase of voltage intensity by Δvbll14-pre= 1480.5% (n = 16,p < 0.01) and ΔCbll14-pre= 230.1% (n = 16,p < 0.01) respectively.Significance: The reason for the differential tendency of increase in <σ>M1suggests an increase in muscle extracellular volumes duringvic-EMS due to the co-effect of venous blood flow velocity and blood lactate metabolism. Based on the conductivity second-order difference images∂2σM1φ∂φ2φand spatial-mean conductivity second-order difference∂2σM1φ∂φ2φ,optimum voltage intensityφOVIis discussed among sixteen volunteer subjects, which increased with a thicker subcutaneous fat layer.
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Affiliation(s)
- Bo Sun
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, Chiba-shi, Japan
| | - Panji Nursetia Darma
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, Chiba-shi, Japan
| | | | | | - Masahiro Takei
- Department of Mechanical Engineering, Graduate School of Science and Engineering, Chiba University, Chiba-shi, Japan
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42
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da Silva SLEF, Kaniadakis G. Robust parameter estimation based on the generalized log-likelihood in the context of Sharma-Taneja-Mittal measure. Phys Rev E 2021; 104:024107. [PMID: 34525653 DOI: 10.1103/physreve.104.024107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/21/2021] [Indexed: 11/07/2022]
Abstract
The problem of obtaining physical parameters that cannot be directly measured from observed data arises in several scientific fields. In the classic approach, the well-known maximum likelihood estimation associated with a Gaussian distribution is employed to obtain the model parameters of a complex system. Although this approach is quite popular in statistical physics, only a handful of spurious observations (outliers) make this approach ineffective, violating the Gauss-Markov theorem. In this work, starting from the generalized logarithmic function associated to the Sharma-Taneja-Mittal (STM) information measure, we propose an outlier-resistant approach based on the generalized log-likelihood estimation. In particular, our proposal deforms the Gaussian distribution based on a two-parameter generalization of the ordinary logarithmic function. We have tested the effectiveness of our proposal considering a classic geophysical inverse problem with a very noisy data set. The results show that the task of obtaining physical parameters based on the STM measure from noisy data with several outliers outperforms the classic approach, and therefore, our proposal is a useful tool for statistical physics, information theory, and statistical inference problems.
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Affiliation(s)
- Sérgio Luiz E F da Silva
- Seismic Inversion and Imaging Group, Federal Fluminense University, 24210-346 Niterói, RJ, Brazil
| | - G Kaniadakis
- Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy
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43
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Hentze B, Muders T, Hoog Antink C, Putensen C, Larsson A, Hedenstierna G, Walter M, Leonhardt S. A model-based source separation algorithm for lung perfusion imaging using electrical impedance tomography. Physiol Meas 2021; 42. [PMID: 34167091 DOI: 10.1088/1361-6579/ac0e84] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/24/2021] [Indexed: 11/11/2022]
Abstract
Objective. Electrical impedance tomography (EIT) for lung perfusion imaging is attracting considerable interest in intensive care, as it might open up entirely new ways to adjust ventilation therapy. A promising technique is bolus injection of a conductive indicator to the central venous catheter, which yields the indicator-based signal (IBS). Lung perfusion images are then typically obtained from the IBS using the maximum slope technique. However, the low spatial resolution of EIT results in a partial volume effect (PVE), which requires further processing to avoid regional bias.Approach. In this work, we repose the extraction of lung perfusion images from the IBS as a source separation problem to account for the PVE. We then propose a model-based algorithm, called gamma decomposition (GD), to derive an efficient solution. The GD algorithm uses a signal model to transform the IBS into a parameter space where the source signals of heart and lung are separable by clustering in space and time. Subsequently, it reconstructs lung model signals from which lung perfusion images are unambiguously extracted.Main results. We evaluate the GD algorithm on EIT data of a prospective animal trial with eight pigs. The results show that it enables lung perfusion imaging using EIT at different stages of regional impairment. Furthermore, parameters of the source signals seem to represent physiological properties of the cardio-pulmonary system.Significance. This work represents an important advance in IBS processing that will likely reduce bias of EIT perfusion images and thus eventually enable imaging of regional ventilation/perfusion (V/Q) ratio.
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Affiliation(s)
- Benjamin Hentze
- Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany.,Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Thomas Muders
- Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Christoph Hoog Antink
- Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany.,Biomedical Engineering, TU Darmstadt, Darmstadt, Germany
| | - Christian Putensen
- Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Anders Larsson
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | | | - Marian Walter
- Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Steffen Leonhardt
- Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
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44
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Electrical impedance tomography: A compass for the safe route to optimal PEEP. Respir Med 2021; 187:106555. [PMID: 34352563 DOI: 10.1016/j.rmed.2021.106555] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 11/20/2022]
Abstract
Setting the proper level of positive end-expiratory pressure (PEEP) is a cornerstone of lung protective ventilation. PEEP keeps the alveoli open at the end of expiration, thus reducing atelectrauma and shunt. However, excessive PEEP may contribute to alveolar overdistension. Electrical impedance tomography (EIT) is a non-invasive bedside tool that monitors in real-time ventilation distribution. Aim of this narrative review is summarizing the techniques for EIT-guided PEEP titration, while providing useful insights to enhance comprehension on advantages and limits of EIT for current and future users. EIT detects thoracic impedance to alternating electrical currents between pairs of electrodes and, through the analysis of its temporal and spatial variation, reconstructs a two-dimensional slice image of the lung depicting regional variation of ventilation and perfusion. Several EIT-based methods have been proposed for PEEP titration. The first described technique estimates the variations of regional lung compliance during a decremental PEEP trial, after lung recruitment. The optimal PEEP value is represented by the best compromise between lung collapse and overdistension. Later on, a second technique assessing alveolar recruitment by variation of the end-expiratory lung impedance was validated. Finally, the global inhomogeneity index and the regional ventilation delay, two EIT-derived parameters, showed promising results selecting the optimal PEEP value as the one that presents the lowest global inhomogeneity index or the lowest regional ventilation delay. In conclusion EIT represents a promising technique to individualize PEEP in mechanically ventilated patients. Whether EIT is the best technique for this purpose and the overall influence of personalizing PEEP on clinical outcome remains to be determined.
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Muders T, Hentze B, Kreyer S, Wodack KH, Leonhardt S, Hedenstierna G, Wrigge H, Putensen C. Measurement of Electrical Impedance Tomography-Based Regional Ventilation Delay for Individualized Titration of End-Expiratory Pressure. J Clin Med 2021; 10:jcm10132933. [PMID: 34208890 PMCID: PMC8267627 DOI: 10.3390/jcm10132933] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 01/01/2023] Open
Abstract
RATIONALE Individualized positive end-expiratory pressure (PEEP) titration might be beneficial in preventing tidal recruitment. To detect tidal recruitment by electrical impedance tomography (EIT), the time disparity between the regional ventilation curves (regional ventilation delay inhomogeneity [RVDI]) can be measured during controlled mechanical ventilation when applying a slow inflation of 12 mL/kg of body weight (BW). However, repeated large slow inflations may result in high end-inspiratory pressure (PEI), which might limit the clinical applicability of this method. We hypothesized that PEEP levels that minimize tidal recruitment can also be derived from EIT-based RVDI through the use of reduced slow inflation volumes. METHODS Decremental PEEP trials were performed in 15 lung-injured pigs. The PEEP level that minimized tidal recruitment was estimated from EIT-based RVDI measurement during slow inflations of 12, 9, 7.5, or 6 mL/kg BW. We compared RVDI and PEI values resulting from different slow inflation volumes and estimated individualized PEEP levels. RESULTS RVDI values from slow inflations of 12 and 9 mL/kg BW showed excellent linear correlation (R2 = 0.87, p < 0.001). Correlations decreased for RVDI values from inflations of 7.5 (R2 = 0.68, p < 0.001) and 6 (R2 = 0.42, p < 0.001) mL/kg BW. Individualized PEEP levels estimated from 12 and 9 mL/kg BW were comparable (bias -0.3 cm H2O ± 1.2 cm H2O). Bias and scatter increased with further reduction in slow inflation volumes (for 7.5 mL/kg BW, bias 0 ± 3.2 cm H2O; for 6 mL/kg BW, bias 1.2 ± 4.0 cm H2O). PEI resulting from 9 mL/kg BW inflations were comparable with PEI during regular tidal volumes. CONCLUSIONS PEEP titration to minimize tidal recruitment can be individualized according to EIT-based measurement of the time disparity of regional ventilation courses during slow inflations with low inflation volumes. This sufficiently decreases PEI and may reduce potential clinical risks.
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Affiliation(s)
- Thomas Muders
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany; (B.H.); (S.K.); (K.H.W.); (C.P.)
- Correspondence:
| | - Benjamin Hentze
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany; (B.H.); (S.K.); (K.H.W.); (C.P.)
| | - Stefan Kreyer
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany; (B.H.); (S.K.); (K.H.W.); (C.P.)
| | - Karin Henriette Wodack
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany; (B.H.); (S.K.); (K.H.W.); (C.P.)
| | - Steffen Leonhardt
- Chair for Medical Information Technology, RWTH Aachen University, 52074 Aachen, Germany;
| | - Göran Hedenstierna
- Department of Medical Sciences, Clinical Physiology, Uppsala University, 75185 Uppsala, Sweden;
| | - Hermann Wrigge
- Department of Anesthesiology, Intensive Care and Emergency Medicine, Pain Therapy, Bergmannstrost Hospital Halle, 06112 Halle, Germany;
| | - Christian Putensen
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, 53127 Bonn, Germany; (B.H.); (S.K.); (K.H.W.); (C.P.)
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Raisis AL, Mosing M, Hosgood GL, Secombe CJ, Adler A, Waldmann AD. The use of electrical impedance tomography (EIT) to evaluate pulse rate in anaesthetised horses. Vet J 2021; 273:105694. [PMID: 34148609 DOI: 10.1016/j.tvjl.2021.105694] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 05/04/2021] [Accepted: 05/12/2021] [Indexed: 10/21/2022]
Abstract
Electrical impedance tomography (EIT) provides clinically useful lung images; however, it would be an advantage to extract additional cardiovascular information from the data. The aim of this study was to evaluate if cardiac-related changes measured by EIT can be used to measure pulse rate (PR) under physiological as well as high and low blood pressure states in anaesthetised horses. Electrical impedance tomography data and PR from seven horses anaesthetised in dorsal recumbency were recorded over 1 min during mechanical ventilation and 1 min of apnoea. Data were collected at four measurement time points; before and during intravenous administration of nitroprusside and phenylephrine, respectively. Nine pixels, estimated to represent the heart, were chosen from the EIT image. A novel algorithm detected peaks of impedance change for these pixels over 10 s intervals. Concurrent PR measured using an invasive blood pressure trace, was recorded every 10 s. EIT- and pulse-rate data were compared using Bland-Altman assessment for multiple measurements on each horse. Overall, 288 paired datasets from six of seven horses were available for analysis. There was excellent agreement for baseline measurements, as well as during hypertension and hypotension, with a bias of -0.26 and lower and upper limit of agreement at -2.22 (95% confidence intervals [CI], -2.89 to -1.86) and 1.69 (95% CI, 1.34-2.36) beats per min, respectively. EIT can be used to evaluate PR using cardiac-related impedance changes. More work is required to determine bias that might occur in anaesthetised horses in other recumbencies or clinical situations.
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Affiliation(s)
- A L Raisis
- School of Veterinary Medicine, College of SHEE, Murdoch University, South Street, Perth, WA, Australia
| | - M Mosing
- School of Veterinary Medicine, College of SHEE, Murdoch University, South Street, Perth, WA, Australia.
| | - G L Hosgood
- School of Veterinary Medicine, College of SHEE, Murdoch University, South Street, Perth, WA, Australia
| | - C J Secombe
- School of Veterinary Medicine, College of SHEE, Murdoch University, South Street, Perth, WA, Australia
| | - A Adler
- Systems and Computer Engineering, Carleton University, Ottawa, Canada
| | - A D Waldmann
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
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Abstract
PURPOSE OF REVIEW Among noninvasive lung imaging techniques that can be employed at the bedside electrical impedance tomography (EIT) and lung ultrasound (LUS) can provide dynamic, repeatable data on the distribution regional lung ventilation and response to therapeutic manoeuvres.In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT and Point of Care Ultrasound (PoCUS, mainly but not limited to LUS) in the management of mechanically ventilated patients. RECENT FINDINGS The use of EIT in clinical practice is supported by several studies demonstrating good correlation between impedance tomography data and other validated methods of assessing lung aeration during mechanical ventilation. Similarly, LUS also correlates with chest computed tomography in assessing lung aeration, its changes and several pathological conditions, with superiority over other techniques. Other PoCUS applications have shown to effectively complement the LUS ultrasound assessment of the mechanically ventilated patient. SUMMARY Bedside techniques - such as EIT and PoCUS - are becoming standards of the care for mechanically ventilated patients to monitor the changes in lung aeration, ventilation and perfusion in response to treatment and to assess weaning from mechanical ventilation.
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L'Her E, Nazir S, Pateau V, Visvikis D. Accuracy of noncontact surface imaging for tidal volume and respiratory rate measurements in the ICU. J Clin Monit Comput 2021; 36:775-783. [PMID: 33886075 PMCID: PMC8060689 DOI: 10.1007/s10877-021-00708-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/13/2021] [Indexed: 01/24/2023]
Abstract
Tidal volume monitoring may help minimize lung injury during respiratory assistance. Surface imaging using time-of-flight camera is a new, non-invasive, non-contact, radiation-free, and easy-to-use technique that enables tidal volume and respiratory rate measurements. The objectives of the study were to determine the accuracy of Time-of-Flight volume (VTTOF) and respiratory rate (RRTOF) measurements at the bedside, and to validate its application for spontaneously breathing patients under high flow nasal canula. Data analysis was performed within the ReaSTOC data-warehousing project (ClinicalTrials.gov identifier NCT02893462). All data were recorded using standard monitoring devices, and the computerized medical file. Time-of-flight technique used a Kinect V2 (Microsoft, Redmond, WA, USA) to acquire the distance information, based on measuring the phase delay between the emitted light-wave and received backscattered signals. 44 patients (32 under mechanical ventilation; 12 under high-flow nasal canula) were recorded. High correlation (r = 0.84; p < 0.001), with low bias (-1.7 mL) and acceptable deviation (75 mL) was observed between VTTOF and VTREF under ventilation. Similar performance was observed for respiratory rate (r = 0.91; p < 0.001; bias < 1b/min; deviation ≤ 5b/min). Measurements were possible for all patients under high-flow nasal canula, detecting overdistension in 4 patients (tidal volume > 8 mL/kg) and low ventilation in 6 patients (tidal volume < 6 mL/kg). Tidal volume monitoring using time-of-flight camera (VTTOF) is correlated to reference values. Time-of-flight camera enables continuous and non-contact respiratory monitoring under high-flow nasal canula, and enables to detect tidal volume and respiratory rate changes, while modifying flow. It enables respiratory monitoring for spontaneously patients, especially while using high-flow nasal oxygenation.
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Affiliation(s)
- Erwan L'Her
- Médecine Intensive Et Réanimation, CHRU de La Cavale Blanche, Bvd. Tanguy-Prigent, 29609, BREST Cedex, France. .,LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France.
| | - Souha Nazir
- LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France
| | - Victoire Pateau
- Médecine Intensive Et Réanimation, CHRU de La Cavale Blanche, Bvd. Tanguy-Prigent, 29609, BREST Cedex, France
| | - Dimitris Visvikis
- LATIM INSERM UMR 1101, Université de Bretagne Occidentale, BREST, France
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Measurement-Based Domain Parameter Optimization in Electrical Impedance Tomography Imaging. SENSORS 2021; 21:s21072507. [PMID: 33916751 PMCID: PMC8038345 DOI: 10.3390/s21072507] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/22/2022]
Abstract
This paper discusses the optimization of domain parameters in electrical impedance tomography-based imaging. Precise image reconstruction requires accurate, well-correlated physical and numerical finite element method (FEM) models; thus, we employed the Nelder–Mead algorithm and a complete electrode model to evaluate the individual parameters, including the initial conductivity, electrode misplacement, and shape deformation. The optimization process was designed to calculate the parameters of the numerical model before the image reconstruction. The models were verified via simulation and experimental measurement with single source current patterns. The impact of the optimization on the above parameters was reflected in the applied image reconstruction process, where the conductivity error dropped by 6.16% and 11.58% in adjacent and opposite driving, respectively. In the shape deformation, the inhomogeneity area ratio increased by 11.0% and 48.9%; the imprecise placement of the 6th electrode was successfully optimized with adjacent driving; the conductivity error dropped by 12.69%; and the inhomogeneity localization exhibited a rise of 66.7%. The opposite driving option produces undesired duality resulting from the measurement pattern. The designed optimization process proved to be suitable for correlating the numerical and the physical models, and it also enabled us to eliminate imaging uncertainties and artifacts.
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Tidal volume and stroke volume changes caused by respiratory events during sleep and their relationship with OSA severity: a pilot study. Sleep Breath 2021; 25:2025-2038. [PMID: 33683548 DOI: 10.1007/s11325-021-02334-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/03/2021] [Accepted: 02/19/2021] [Indexed: 10/22/2022]
Abstract
PURPOSE Breath-by-breath tidal volume (TV) and beat-by-beat stroke volume (SV) were continuously measured in patients with OSA undergoing polysomnography (PSG). The objectives were to (1) determine the changes in TV/SV in response to respiratory events and (2) assess the relationship between these changes and the disease severity. METHODS From the PSG data of nine patients with OSA, six different types of respiratory events were identified, i.e., flow limitation (FL), respiratory effort related arousal (RERA), hypopnea with arousal only (Ha), hypopnea with desaturation only (Hd), hypopnea with arousal and desaturation (Had), and apnea. The measured TV and SV values during and after each respiratory event were compared with the pre-event baseline values. RESULTS The mean TV/SV reductions during all hypopneas and apneas were 38.1%/4.2% and 70.5%/8.8%, respectively. Among three different hypopnea types, the reductions in TV during Hd and Had were significantly greater than those during Ha. The TV reductions during Ha and FL were similar. After RERA, Ha, Had, and apnea, there was an overshoot in TV and SV values, whereas there was no overshoot after FL and Hd. During RERA, there was no reduction in TV/SV. CONCLUSIONS The changes in TV during and after each type of respiratory event were significantly different in most cases. The changes in SV between hypopnea and apnea were different with statistical significance. The AHI does not properly account for the ventilation losses caused by respiratory events. Thus, TV measurements might be useful in the future in assessing the OSA severity in conjunction with the AHI.
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