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Frerichs I, Vogt B, Deuss K, Hennig V, Schädler D, Händel C. Distribution of regional lung function in upright healthy subjects determined by electrical impedance tomography in two chest examination planes. Physiol Meas 2024; 45:015001. [PMID: 38096575 DOI: 10.1088/1361-6579/ad15ac] [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: 09/05/2023] [Accepted: 12/14/2023] [Indexed: 12/20/2023]
Abstract
Objective. The variation in pulmonary gas content induced by ventilation is not uniformly distributed in the lungs. The aim of our study was to characterize the differences in spatial distribution of ventilation in two transverse sections of the chest using electrical impedance tomography (EIT).Approach. Twenty adult never-smokers, 10 women and 10 men (mean age ± SD, 31 ± 9 years), were examined in a sitting position with the EIT electrodes placed consecutively in a caudal (6th intercostal space) and a cranial (4th intercostal space) chest location. EIT data were acquired during quiet breathing, slow and forced full expiration manoeuvres. Impedance variations representing tidal volume (VT), vital capacity (VC), forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were calculated at the level of individual image pixels and their spatial distribution was determined using the following EIT measures: the centres of ventilation in ventrodorsal (CoVvd) and right-to-left direction (CoVrl), the dorsal and right fractions of ventilation, the coefficient of variation (CV) and the global inhomogeneity (GI) index.Main results. The sums of pixel ventilation-related impedance variations reproduced reliably the volumetric dissimilarities amongVT, VC, FEV1and FVC, with no significant differences noted between the two examination planes. Significant differences in ventilation distribution were found between the planes during tidal breathing and slow full expiration, mainly regarding the ventrodorsal direction, with higher values of CoVvdand dorsal fraction of ventilation in the caudal plane (p< 0.01). No significant differences in the spatial distribution of FEV1and FVC were detected between the examination planes.Significance. The spatial distribution of ventilation differed between the two examination planes only during the relaxed (quiet breathing and slow VC manoeuvre) but not during the forced ventilation. This effect is attributable to the differences in thoracoabdominal mechanics between these types of ventilation.
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Affiliation(s)
- I Frerichs
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
| | - B Vogt
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
| | - K Deuss
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
| | - V Hennig
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
| | - D Schädler
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
| | - C Händel
- University Medical Centre Schleswig-Holstein, Campus Kiel, Department of Anaesthesiology and Intensive Care Medicine, Kiel, Germany
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Bayford R, Sadleir R, Frerichs I. Advances in electrical impedance tomography and bioimpedance including applications in COVID-19 diagnosis and treatment. Physiol Meas 2022; 43. [DOI: 10.1088/1361-6579/ac4e6c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 01/24/2022] [Indexed: 11/12/2022]
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Hu CL, Cheng IC, Huang CH, Liao YT, Lin WC, Tsai KJ, Chi CH, Chen CW, Wu CH, Lin IT, Li CJ, Lin CW. Dry Wearable Textile Electrodes for Portable Electrical Impedance Tomography. SENSORS 2021; 21:s21206789. [PMID: 34696002 PMCID: PMC8537054 DOI: 10.3390/s21206789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 11/16/2022]
Abstract
Electrical impedance tomography (EIT), a noninvasive and radiation-free medical imaging technique, has been used for continuous real-time regional lung aeration. However, adhesive electrodes could cause discomfort and increase the risk of skin injury during prolonged measurement. Additionally, the conductive gel between the electrodes and skin could evaporate in long-term usage and deteriorate the signal quality. To address these issues, in this work, textile electrodes integrated with a clothing belt are proposed to achieve EIT lung imaging along with a custom portable EIT system. The simulation and experimental results have verified the validity of the proposed portable EIT system. Furthermore, the imaging results of using the proposed textile electrodes were compared with commercial electrocardiogram electrodes to evaluate their performance.
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Affiliation(s)
- Chang-Lin Hu
- Industrial Technology Research Institute, Hsinchu 310, Taiwan; (I.-C.C.); (K.-J.T.); (C.-J.L.); (C.-W.L.)
- Correspondence:
| | - I-Cheng Cheng
- Industrial Technology Research Institute, Hsinchu 310, Taiwan; (I.-C.C.); (K.-J.T.); (C.-J.L.); (C.-W.L.)
| | - Chih-Hsien Huang
- Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan; (C.-H.H.); (C.-H.W.)
| | - Yu-Te Liao
- Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan; (Y.-T.L.); (I.-T.L.)
| | - Wei-Chieh Lin
- Division of Critical Care Medicine, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.L.); (C.-W.C.)
| | - Kun-Ju Tsai
- Industrial Technology Research Institute, Hsinchu 310, Taiwan; (I.-C.C.); (K.-J.T.); (C.-J.L.); (C.-W.L.)
| | - Chih-Hsien Chi
- Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan;
| | - Chang-Wen Chen
- Division of Critical Care Medicine, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.L.); (C.-W.C.)
| | - Chia-Hsi Wu
- Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan; (C.-H.H.); (C.-H.W.)
| | - I-Te Lin
- Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan; (Y.-T.L.); (I.-T.L.)
| | - Chien-Ju Li
- Industrial Technology Research Institute, Hsinchu 310, Taiwan; (I.-C.C.); (K.-J.T.); (C.-J.L.); (C.-W.L.)
| | - Chii-Wann Lin
- Industrial Technology Research Institute, Hsinchu 310, Taiwan; (I.-C.C.); (K.-J.T.); (C.-J.L.); (C.-W.L.)
- Department of Biomedical Engineering, National Taiwan University, Taipei 106, Taiwan
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Aqueveque P, Gómez B, Monsalve E, Germany E, Ortega-Bastidas P, Dubo S, Pino EJ. Simple Wireless Impedance Pneumography System for Unobtrusive Sensing of Respiration. SENSORS 2020; 20:s20185228. [PMID: 32937770 PMCID: PMC7571009 DOI: 10.3390/s20185228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022]
Abstract
This extended paper presents the development and implementation at a prototype level of a wireless, low-cost system for the measurement of the electrical bioimpedance of the chest with two channels using the AD5933 in a bipolar electrode configuration to measure impedance pneumography. The measurement device works for impedance measurements ranging from 1 Ω to 1800 Ω. Fifteen volunteers were measured with the prototype. We found that the left hemithorax has higher impedance compared to the right hemithorax, and the acquired signal presents the phases of the respiratory cycle with variations between 1 Ω, in normal breathing, to 6 Ω in maximum inhalation events. The system can measure the respiratory cycle variations simultaneously in both hemithorax with a mean error of -0.18 ± 1.42 BPM (breaths per minute) in the right hemithorax and -0.52 ± 1.31 BPM for the left hemithorax, constituting a useful device for the breathing rate calculation and possible screening applications.
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Affiliation(s)
- Pablo Aqueveque
- Electrical Engineering Department, Faculty of Engineering, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070409, Chile; (P.A.); (B.G.); (E.M.); (E.G.)
| | - Britam Gómez
- Electrical Engineering Department, Faculty of Engineering, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070409, Chile; (P.A.); (B.G.); (E.M.); (E.G.)
| | - Emyrna Monsalve
- Electrical Engineering Department, Faculty of Engineering, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070409, Chile; (P.A.); (B.G.); (E.M.); (E.G.)
| | - Enrique Germany
- Electrical Engineering Department, Faculty of Engineering, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070409, Chile; (P.A.); (B.G.); (E.M.); (E.G.)
| | - Paulina Ortega-Bastidas
- Kinesiology Department, Faculty of Medicine, Universidad de Concepción, Chacabuco 1401, Concepción 4070409, Chile; (P.O.-B.); (S.D.)
| | - Sebastián Dubo
- Kinesiology Department, Faculty of Medicine, Universidad de Concepción, Chacabuco 1401, Concepción 4070409, Chile; (P.O.-B.); (S.D.)
| | - Esteban J. Pino
- Electrical Engineering Department, Faculty of Engineering, Universidad de Concepción, Edmundo Larenas 219, Concepción 4070409, Chile; (P.A.); (B.G.); (E.M.); (E.G.)
- Correspondence: ; Tel.: +56-9-81989266
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Gibas C, Grunewald A, Wunderlich HW, Marx P, Bruck R. A wearable EIT system for detection of muscular activity in the extremities. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:2496-2499. [PMID: 31946404 DOI: 10.1109/embc.2019.8856792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Electrical Impedance Tomography (EIT) is a method for measuring physiological states and processes that can be used as an imaging method for muscular activities. In addition to the medical evaluation of the EIT data of the lung, this technology can be used to make a statement about muscular activity in the extremities. This paper presents a developed, mobile EIT system that can be used with an electrode bracelet on the arm. In a rst study, the EIT data for different hand gestures were evaluated.
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