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Yang L, Gao Z, Cao X, Sun S, Wang C, Wang H, Dai J, Liu Y, Qin Y, Dai M, Guo W, Zhang B, Zhao K, Zhao Z. Electrical impedance tomography as a bedside assessment tool for COPD treatment during hospitalization. Front Physiol 2024; 15:1352391. [PMID: 38562620 PMCID: PMC10982416 DOI: 10.3389/fphys.2024.1352391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
For patients with chronic obstructive pulmonary disease (COPD), the assessment of the treatment efficacy during hospitalization is of importance to the optimization of clinical treatments. Conventional spirometry might not be sensitive enough to capture the regional lung function development. The study aimed to evaluate the feasibility of using electrical impedance tomography (EIT) as an objective bedside evaluation tool for the treatment of acute exacerbation of COPD (AECOPD). Consecutive patients who required hospitalization due to AECOPD were included prospectively. EIT measurements were conducted at the time of admission and before the discharge simultaneously when a forced vital capacity maneuver was conducted. EIT-based heterogeneity measures of regional lung function were calculated based on the impedance changes over time. Surveys for attending doctors and patients were designed to evaluate the ease of use, feasibility, and overall satisfaction level to understand the acceptability of EIT measurements. Patient-reported outcome assessments were conducted. User's acceptance of EIT technology was investigated with a five-dimension survey. A total of 32 patients were included, and 8 patients were excluded due to the FVC maneuver not meeting the ATS criteria. Spirometry-based lung function was improved during hospitalization but not significantly different (FEV1 %pred.: 35.8% ± 6.7% vs. 45.3% ± 8.8% at admission vs. discharge; p = 0.11. FVC %pred.: 67.8% ± 0.4% vs. 82.6% ± 5.0%; p = 0.15. FEV1/FVC: 0.41 ± 0.09 vs. 0.42 ± 0.07, p = 0.71). The symptoms of COPD were significantly improved, but the correlations between the improvement of symptoms and spirometry FEV1 and FEV1/FVC were low (R = 0.1 and -0.01, respectively). The differences in blood gasses and blood tests were insignificant. All but one EIT-based regional lung function parameter were significantly improved after hospitalization. The results highly correlated with the patient-reported outcome assessment (R > 0.6, p < 0.001). The overall acceptability score of EIT measurement for both attending physicians and patients was high (4.1 ± 0.8 for physicians, 4.5 ± 0.5 for patients out of 5). These results demonstrated that it was feasible and acceptable to use EIT as an objective bedside evaluation tool for COPD treatment efficacy.
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Affiliation(s)
- Lin Yang
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Zhijun Gao
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Xinsheng Cao
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Shuying Sun
- Department of Pulmonary and Critical Care Medicine, 986th Hospital of Air Force, Air Force Medical University, Xi’an, China
| | - Chunchen Wang
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Hang Wang
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Jing Dai
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Yang Liu
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Yilong Qin
- Department of Aerospace Medicine, Air Force Medical University, Xi’an, China
| | - Meng Dai
- Department of Biomedical Engineering, Air Force Medical University, Xi’an, China
| | - Wei Guo
- Department of Pulmonary and Critical Care Medicine, 986th Hospital of Air Force, Air Force Medical University, Xi’an, China
| | - Binghua Zhang
- Department of Pulmonary and Critical Care Medicine, 986th Hospital of Air Force, Air Force Medical University, Xi’an, China
| | - Ke Zhao
- Department of Pulmonary and Critical Care Medicine, 986th Hospital of Air Force, Air Force Medical University, Xi’an, China
| | - Zhanqi Zhao
- School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
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Rosén J, Frykholm P, Jonsson Fagerlund M, Pellegrini M, Campoccia Jalde F, von Oelreich E, Fors D. Lung impedance changes during awake prone positioning in COVID-19. A non-randomized cross-over study. PLoS One 2024; 19:e0299199. [PMID: 38381730 PMCID: PMC10880988 DOI: 10.1371/journal.pone.0299199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 02/01/2024] [Indexed: 02/23/2024] Open
Abstract
BACKGROUND The effects of awake prone positioning (APP) on respiratory mechanics in patients with COVID-19 are not well characterized. The aim of this study was to investigate changes of global and regional lung volumes during APP compared with the supine position using electrical lung impedance tomography (EIT) in patients with hypoxemic respiratory failure due to COVID-19. MATERIALS AND METHODS This exploratory non-randomized cross-over study was conducted at two university hospitals in Sweden between January and May 2021. Patients admitted to the intensive care unit with confirmed COVID-19, an arterial cannula in place, a PaO2/FiO2 ratio <26.6 kPa (<200 mmHg) and high-flow nasal oxygen or non-invasive ventilation were eligible for inclusion. EIT-data were recorded at supine baseline, at 30 and 60 minutes after APP-initiation, and 30 minutes after supine repositioning. The primary outcomes were changes in global and regional tidal impedance variation (TIV), center of ventilation (CoV), global and regional delta end-expiratory lung-impedance (dEELI) and global inhomogeneity (GI) index at the end of APP compared with supine baseline. Data were reported as median (IQR). RESULTS All patients (n = 10) were male and age was 64 (47-73) years. There were no changes in global or regional TIV, CoV or GI-index during the intervention. dEELI increased from supine reference value 0 to 1.51 (0.32-3.62) 60 minutes after APP (median difference 1.51 (95% CI 0.19-5.16), p = 0.04) and returned to near baseline values after supine repositioning. Seven patients (70%) showed an increase >0.20 in dEELI during APP. The other EIT-variables did not change during APP compared with baseline. CONCLUSION Awake prone positioning was associated with a transient lung recruiting effect without changes in ventilation distribution measured with EIT in patients with hypoxemic respiratory failure due to COVID-19.
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Affiliation(s)
- Jacob Rosén
- Department of Surgical Sciences, Anaesthesiology and Intensive Care Medicine, Uppsala University, Uppsala, Sweden
| | - Peter Frykholm
- Department of Surgical Sciences, Anaesthesiology and Intensive Care Medicine, Uppsala University, Uppsala, Sweden
| | - Malin Jonsson Fagerlund
- Perioperative Medicine and Intensive Care, Karolinska University Hospital, Solna, Sweden
- Section of Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Solna, Sweden
| | - Mariangela Pellegrini
- Department of Surgical Sciences, Anaesthesiology and Intensive Care Medicine, Uppsala University, Uppsala, Sweden
| | - Francesca Campoccia Jalde
- Perioperative Medicine and Intensive Care, Karolinska University Hospital, Solna, Sweden
- Section of Thoracic Anesthesiology and Intensive Care, Department of Molecular Medicine and Surgery, Karolinska Institutet, Solna, Sweden
| | - Erik von Oelreich
- Perioperative Medicine and Intensive Care, Karolinska University Hospital, Solna, Sweden
- Section of Anesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Solna, Sweden
| | - Diddi Fors
- Department of Surgical Sciences, Anaesthesiology and Intensive Care Medicine, Uppsala University, Uppsala, Sweden
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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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Yang L, Gao Z, Cao X, Fu F, Möller K, Frerichs I, Dai M, Zhao Z. The influence of gravity on electrical impedance tomography measurements during upper body position change. Heliyon 2023; 9:e15910. [PMID: 37215814 PMCID: PMC10192413 DOI: 10.1016/j.heliyon.2023.e15910] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/19/2023] [Accepted: 04/26/2023] [Indexed: 05/24/2023] Open
Abstract
Objective The aim of the study was to examine the influence of gravity on regional ventilation measured by electrical impedance tomography (EIT) with the standard electrode belt position at the 5th intercostal space during tilting from supine to sitting positions. Methods A total of 30 healthy volunteers were examined prospectively in supine position during quiet tidal breathing. Subsequently, the bed was tilted so that the upper body of the subjects achieved 30, 60 and 90° every 3 min. Regional ventilation distribution and end-expiratory lung impedance (EELI) were monitored with EIT throughout the whole experiment. Absolute tidal volumes were measured with spirometry and the volume-impedance ratio was calculated for each position. Results The volume-impedance ratio did not differ statistically between the studied body positions but 11 subjects exhibited a large change in ratio at one of the positions (outside 99.3% coverage). In general, ventilation distribution became more heterogeneous and moved towards dorsal regions as the upper body was tilted to 90-degree position. EELI increased and tidal volume decreased. The lung regions identified at various positions differed significantly. Conclusion Gravity has non-negligible influence on EIT data, as the upper body tilted from supine to sitting positions. The standard electrode belt position might be reconsidered if ventilation distribution is to be compared between supine and sitting positions.
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Affiliation(s)
- Lin Yang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhijun Gao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Xinsheng Cao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Knut Möller
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre of Schleswig-Holstein Campus Kiel, Germany
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
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Electrical Impedance Tomography (EIT) in a Patient Suffering from Post-COVID Syndrome with Dyspnea: A Case Report. Diagnostics (Basel) 2022; 12:diagnostics12102284. [DOI: 10.3390/diagnostics12102284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/14/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Long-term health consequences following COVID-19 disease constitute an increasing problem worldwide. A considerable number of patients still suffer from various symptoms, most commonly dyspnea, months or even years after the acute infection. In these patients, a classical pulmonary function test often yields no significant findings. Subsequently, treating those patients is a challenge for any physician as there are currently no evidence-based treatment plans. Case and methods: We reported the case of a 58-year-old patient who was still suffering from resting dyspnea six months after severe COVID-19 pneumonia. The dyspnea was so pronounced that the patient was supplied with home oxygen, which they used as needed. The regional distribution of ventilation in the lungs was studied twice utilizing noninvasive electrical impedance tomography (EIT). The first examination showed distinct inhomogeneities of regional ventilation, a regional ventilation delay (RVD) of 15%, and pronounced pendelluft phenomena. Seven weeks after treatment with budesonide and physical therapy, the patient reported a clear subjective improvement in complaints. Accordingly, the regional distribution of ventilation also improved. Conclusion: Electrical impedance tomography might be a promising method to assess lung function in post-COVID patients; however, controlled and larger studies are necessary.
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Kuk WJ, Wright NR. Bedside Diagnosis of Pulmonary Embolism Using Electrical Impedance Tomography: A Case Report. A A Pract 2022; 16:e01606. [DOI: 10.1213/xaa.0000000000001606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Zhao Z, Chen TF, Teng HC, Wang YC, Chang MY, Chang HT, Frerichs I, Fu F, Moeller K. Is there a need for individualized adjustment of electrode belt position during EIT-guided titration of positive end-expiratory pressure? Physiol Meas 2022; 43. [PMID: 35617942 DOI: 10.1088/1361-6579/ac73d6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/26/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The aim of the present study was to evaluate the variation of tidal volume-to-impedance ratio (VT/ZT) during positive end-expiratory pressure (PEEP) titration with electrical impedance tomography (EIT) measurement. APPROACH Forty-two patients with acute respiratory distress syndrome were retrospectively analyzed. An incremental and subsequently a decremental PEEP trial were performed with steps of 2 cmH2O and duration of 2 minutes per step during volume-controlled ventilation with decelerating flow. EIT measurement was conducted in the 5th intercostal space and VT was recorded simultaneously. The variation of VT/ZT (RatioV) was defined as the changes in percentage to average ratio per cmH2O PEEP change. A z-score>1 was considered as a significant variation and an implication that the measurement plane was inadequate. MAIN RESULTS The RatioV of 42 patients was 1.29±0.80 %∙cmH2O-1. A z-score of 1 corresponded to the variation of 2.09 %∙cmH2O-1. Seven patients (16.7%) had a z-score>1 and showed either positive or negative correlation between the volume-to-impedance ratio and PEEP. SIGNIFICANCE Electrode placement at 5th intercostal space might not be ideal for every individual during EIT measurement. Evaluation of volume-to-impedance ratio variation is necessary for patients undergoing maneuvers with wide alteration in absolute lung volume.
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Affiliation(s)
- Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Changle Rd. 167, Xi'an, 710032, CHINA
| | - Tsai-Fen Chen
- Far Eastern Memorial Hospital, x, New Taipei City, New Taipei City, x, TAIWAN
| | - Hui-Chen Teng
- Far Eastern Memorial Hospital, x, New Taipei City, New Taipei City, x, TAIWAN
| | - Yi-Chun Wang
- Far Eastern Memorial Hospital, x, New Taipei City, New Taipei City, x, TAIWAN
| | - Mei-Yun Chang
- Far Eastern Memorial Hospital, x, New Taipei City, New Taipei City, x, TAIWAN
| | - Hou-Tai Chang
- Far Eastern Memorial Hospital, z, New Taipei City, New Taipei City, x, TAIWAN
| | - Inez Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein Campus Kiel, x, Kiel, x, GERMANY
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, x, Xi'an, x, CHINA
| | - Knut Moeller
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Strasse 17, Villingen-Schwenningen, D-78054, GERMANY
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Beazley S, Focken A, Fernandez-Parra R, Thomas K, Adler A, Duke-Novakovski T. Evaluation of lung ventilation distribution using electrical impedance tomography in standing sedated horses with capnoperitoneum. Vet Anaesth Analg 2022; 49:382-389. [DOI: 10.1016/j.vaa.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 11/29/2022]
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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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Effects of PEEP on the relationship between tidal volume and total impedance change measured via electrical impedance tomography (EIT). J Clin Monit Comput 2022; 36:325-334. [PMID: 33492490 PMCID: PMC7829490 DOI: 10.1007/s10877-021-00651-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/06/2021] [Indexed: 01/31/2023]
Abstract
Electrical impedance tomography (EIT) is used in lung physiology monitoring. There is evidence that EIT is linearly associated with global tidal volume (VT) in clinically healthy patients where no positive end-expiratory pressure (PEEP) is applied. This linearity has not been challenged by altering lung conditions. The aim of this study was to determine the effect of PEEP on VT estimation, using EIT technology and spirometry, and observe the stability of the relationship under changing lung conditions. Twelve male castrated cattle (Steer), mean age 7.8 months (SD ± 1.7) were premedicated with xylazine followed by anaesthesia induction with ketamine and maintenance with halothane in oxygen via an endotracheal tube. An EIT belt was applied around the thorax at the level of the fifth intercostal space. Volume controlled ventilation was used. PEEP was increased in a stepwise manner from 0 to 5, 10 and 15 cmH2O. At each PEEP, the VT was increased stepwise from 5 to 10 and 15 mL kg-1. After a minute of stabilisation, total impedance change (VTEIT), using EIT and VT measured by a spirometer connected to a flow-partitioning device (VTSpiro) was recorded for the following minute before changing ventilator settings. Data was analysed using linear regression and multi variable analysis. There was a linear relationship between VTEIT and VTSpiro at all levels of PEEP with an R2 of 0.71, 0.68, 0.63 and 0.63 at 0, 5, 10 and 15 cmH2O, respectively. The variance in VTEIT was best described by peak inspiratory pressure (PIP) and PEEP (adjusted R2 0.82) while variance in VTSpiro was best described by PIP and airway deadspace (adjusted R2 0.76). The relationship between VTEIT and VTSpiro remains linear with changes in tidal volume, and stable across altered lung conditions. This may have application for monitoring and assessment in vivo.
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Song X, Yang D, Yang M, Bai Y, Qin B, Tian S, Song G, Guo X, Dong R, Men Y, Liu Z, Liu X, Wang C. Effect of Electrical Impedance Tomography-Guided Early Mobilization in Patients After Major Upper Abdominal Surgery: Protocol for a Prospective Cohort Study. Front Med (Lausanne) 2021; 8:710463. [PMID: 34957133 PMCID: PMC8695759 DOI: 10.3389/fmed.2021.710463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Pulmonary complications are common in patients after upper abdominal surgery, resulting in poor clinical outcomes and increased costs of hospitalization. Enhanced Recovery After Surgery Guidelines strongly recommend early mobilization post-operatively; however, the quality of the evidence is poor, and indicators for quantifying the effectiveness of early mobilization are lacking. This study will evaluate the effectiveness of early mobilization in patients undergoing an upper abdominal surgery using electrical impedance tomography (EIT). Specifically, we will use EIT to assess and compare the lung ventilation distribution among various regions of interest (ROI) before and after mobilization in this patient population. Additionally, we will assess the temporal differences in the distribution of ventilation in various ROI during mobilization in an effort to develop personalized activity programs for this patient population. Methods: In this prospective, single-center cohort study, we aim to recruit 50 patients after upper abdominal surgery between July 1, 2021 and June 30, 2022. This study will use EIT to quantify the ventilation distribution among different ROI. On post-operative day 1, the nurses will assist the patient to sit on the chair beside the bed. Patient's heart rate, blood pressure, oxygen saturation, respiratory rate, and ROI 1-4 will be recorded before the mobilization as baseline. These data will be recorded again at 15, 30, 60, 90, and 120 min after mobilization, and the changes in vital signs and ROI 1-4 values at each time point before and after mobilization will be compared. Ethics and Dissemination: The study protocol has been approved by the Institutional Review Board of Liaocheng Cardiac Hospital (2020036). The trial is registered at chictr.org.cn with identifier ChiCTR2100042877, registered on January 31, 2021. The results of the study will be presented at relevant national and international conferences and submitted to international peer-reviewed journals. There are no plans to communicate results specifically to participants. Important protocol modifications, such as changes to eligibility criteria, outcomes, or analyses, will be communicated to all relevant parties (including investigators, Institutional Review Board, trial participants, trial registries, journals, and regulators) as needed via email or in-person communication.
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Affiliation(s)
- Xuan Song
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Daqiang Yang
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Maopeng Yang
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Yahu Bai
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Bingxin Qin
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Shoucheng Tian
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Gangbing Song
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Xiuyan Guo
- Education Department, Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Ranran Dong
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Yuanyuan Men
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Ziwei Liu
- Internal Medicine, Qingdao University, Qingdao, China
| | - Xinyan Liu
- Intensive Care Unit (ICU), Liaocheng Cardiac Hospital, Liaocheng, China.,Intensive Care Unit (ICU), Dong E Hospital Affiliated to Shandong First Medical University, Liaocheng, China
| | - Chunting Wang
- Intensive Care Unit (ICU), Shandong Provincial Hospital Affiliated to Shandong First Medical University, Liaocheng, China
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Hochhausen N, Kapell T, Dürbaum M, Follmann A, Rossaint R, Czaplik M. Monitoring postoperative lung recovery using electrical impedance tomography in post anesthesia care unit: an observational study. J Clin Monit Comput 2021; 36:1205-1212. [PMID: 34542735 PMCID: PMC9294009 DOI: 10.1007/s10877-021-00754-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/29/2021] [Indexed: 11/26/2022]
Abstract
With electrical impedance tomography (EIT) recruitment and de-recruitment phenomena can be quantified and monitored at bedside. The aim was to examine the feasibility of EIT with respect to monitor atelectasis formation and resolution in the post anesthesia care unit (PACU). In this observational study, 107 postoperative patients were investigated regarding the presence and recovery of atelectasis described by the EIT-derived parameters Global Inhomogeneity Index (GI Index), tidal impedance variation (TIV), and the changes in end-expiratory lung impedance (ΔEELI). We examined whether the presence of obesity (ADP group) has an influence on pulmonary recovery compared to normal weight patients (NWP group). During the stay at PACU, measurements were taken every 15 min. GI Index, TIV, and ΔEELI were calculated for each time point. 107 patients were monitored and EIT-data of 16 patients were excluded for various reasons. EIT-data of 91 patients were analyzed off-line. Their length of stay averaged 80 min (25th and 75th quartile 52–112). The ADP group demonstrated a significantly higher GI Index at PACU arrival (p < 0.001). This finding disappeared during their stay at the PACU. Additionally, the ADP group showed a significant increase in ΔEELI between PACU arrival and discharge (p = 0.025). Furthermore, TIV showed a significantly lower value during the first 90 min of PACU stay as compared to the time period thereafter (p = 0.036). Our findings demonstrate that obesity has an influence on intraoperative atelectasis formation and de-recruitment during PACU stay. The application of EIT in spontaneously breathing PACU patients seems meaningful in monitoring pulmonary recovery.
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Affiliation(s)
- Nadine Hochhausen
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany.
| | - Torsten Kapell
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Martin Dürbaum
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Andreas Follmann
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Rolf Rossaint
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Michael Czaplik
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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13
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Pigatto AV, Kao TJ, Mueller JL, Baker CD, DeBoer EM, Kupfer O. Electrical impedance tomography detects changes in ventilation after airway clearance in spinal muscular atrophy type I. Respir Physiol Neurobiol 2021; 294:103773. [PMID: 34400355 DOI: 10.1016/j.resp.2021.103773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 04/06/2021] [Accepted: 08/05/2021] [Indexed: 11/18/2022]
Abstract
The effect of mechanical insufflation-exsufflation (MIE) for airway clearance in patients with spinal muscular atrophy type I (SMA-I) on the distribution of ventilation in the lung is unknown, as is the duration of its beneficial effects. A pilot study to investigate the feasibility of using three dimensional (3-D) electrical impedance tomography (EIT) images to estimate lung volumes pre- and post-MIE for assessing the effectiveness of mechanical insufflation-exsufflation (MIE) was conducted in 6 pediatric patients with SMA-I in the neuromuscular clinic at Children's Hospital Colorado. EIT data were collected before, during, and after the MIE procedure on two rows of 16 electrodes placed around the chest. Lung volumes were computed from the images and compared before, during, and after the MIE procedure to assess the ability of EIT to estimate changes in lung volume during insufflation and exsufflation. Images of pulsatile pulmonary perfusion were computed in subjects able to perform breath-holding. In four of the six subjects, lung volumes during tidal breathing increased after MIE (average change from pre to post MIE was 58.8±55.1 mL). The time-dependent plots of lung volume computed from the EIT data clearly show when the MIE device insufflates and exsufflates air and the rest periods between mechanical coughs. Images of pulmonary pulsatile perfusion were computed from data collected during breathing pauses. The results suggest that EIT holds promise for estimating lung volumes and ventilation/perfusion mismatch, both of which are useful for assessing the effectiveness of MIE in clearing mucus plugs.
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Affiliation(s)
- Andre Viera Pigatto
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, United States
| | - Tzu-Jen Kao
- GE Research, Niskayuna, NY 12309, United States
| | - Jennifer L Mueller
- School of Biomedical Engineering and Department of Mathematics, Colorado State University, Fort Collins, CO 80523, United States.
| | - Christopher D Baker
- Department of Pediatrics, Section of Pulmonary Medicine, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Emily M DeBoer
- Department of Pediatrics, Section of Pulmonary Medicine, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Oren Kupfer
- Department of Pediatrics, Section of Pulmonary Medicine, University of Colorado School of Medicine, Aurora, CO 80045, United States
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14
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Sun XM, Chen GQ, Wang YM, Zhou YM, Chen JR, Cheng KM, Yang YL, Zhang LL, Li HL, Zhou JX. Derecruitment volume assessment derived from pressure-impedance curves with electrical impedance tomography in experimental acute lung injury. J Int Med Res 2021; 48:300060520949037. [PMID: 32816562 PMCID: PMC7444134 DOI: 10.1177/0300060520949037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Objective To investigate the accuracy of derecruitment volume (VDER) assessed by pressure–impedance (P-I) curves derived from electrical impedance tomography (EIT). Methods Six pigs with acute lung injury received decremental positive end-expiratory pressure (PEEP) from 15 to 0 in steps of 5 cmH2O. At the end of each PEEP level, the pressure–volume (P-V) curves were plotted using the low constant flow method and release maneuvers to calculate the VDER between the PEEP of setting levels and 0 cmH2O (VDER-PV). The VDER derived from P-I curves that were recorded simultaneously using EIT was the difference in impedance at the same pressure multiplied by the ratio of tidal volume and corresponding tidal impedance (VDER-PI). The regional P-I curves obtained by EIT were used to estimate VDER in the dependent and nondependent lung. Results The global lung VDER-PV and VDER-PI showed close correlations (r = 0.948, P<0.001); the mean difference was 48 mL with limits of agreement of −133 to 229 mL. Lung derecruitment extended into the whole process of decremental PEEP levels but was unevenly distributed in different lung regions. Conclusions P-I curves derived from EIT can assess VDER and provide a promising method to estimate regional lung derecruitment at the bedside.
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Affiliation(s)
- Xiu-Mei Sun
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Guang-Qiang Chen
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yu-Mei Wang
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yi-Min Zhou
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jing-Ran Chen
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Kun-Ming Cheng
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yan-Lin Yang
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lin-Lin Zhang
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Hong-Liang Li
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jian-Xin Zhou
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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15
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Jiang H, Li Q, Yu X, Zhang C, Li Y, Niu G, Tong ZH, Xi JN, Zhao Z. Ventilation improvement after pneumonia treatment evaluated with electrical impedance tomography: an observational study. Physiol Meas 2021; 42. [PMID: 33971628 DOI: 10.1088/1361-6579/abffbf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 05/10/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Due to radiation exposures, not all patients with pneumonia would receive chest x-ray or CT measurements to confirm treatment effectiveness. The aim of the study was to examine the ability of using electrical impedance tomography (EIT) to evaluate the treatment effectiveness in such patient group. METHODS A total of 35 consecutive patients with non-severe pneumonia was included in this prospective study. The patients received standard treatment according to our internal protocol. EIT measurements were performed in supine position before the treatment start and on day 6 of the treatment period. EIT-based global inhomogeneity (GI) index and center of ventilation index (CoV) were calculated. Clinical pulmonary infection score (CPIS) was obtained at both time points. RESULTS Clinically significant improvements in GI and CoV were found in patient group (ΔGI: -34%±17% and ΔCoV: -10%±11%; p<0.001). Although CPIS was also significantly improved (ΔCPIS -0.70±0.17, p<0.001), no correlations were demonstrated when it compared to ΔGI or ΔCoV. CONCLUSION EIT demonstrated individual improvement of ventilation heterogeneity after standard treatment in non-severe pneumonia, which provided different information compared to CPIS. EIT has the potential to become a routine non-invasive, non-radiative tool to assess pneumonia treatment effectiveness.
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Affiliation(s)
- Hongying Jiang
- Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Beijing, Beijing, CHINA
| | - Qing Li
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Xin Yu
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Chenxi Zhang
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Yi Li
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Guangyu Niu
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Zhao-Hui Tong
- Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Beijing, Beijing, CHINA
| | - Jia-Ning Xi
- Department of Respiratory Rehabilitation Centre, Beijing Rehabilitation Hospital of Capital Medical University, Beijing, CHINA
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, 710032, CHINA
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16
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Use of Electrical Impedance Tomography (EIT) to Estimate Tidal Volume in Anaesthetized Horses Undergoing Elective Surgery. Animals (Basel) 2021; 11:ani11051350. [PMID: 34068514 PMCID: PMC8151473 DOI: 10.3390/ani11051350] [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: 03/08/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022] Open
Abstract
Simple Summary The aim of this study was to explore the usefulness of electrical impedance tomography (EIT), a novel monitoring tool measuring impedance change, to estimate tidal volume (volume of gas in litres moved in and out the airways and lungs with each breath) in anaesthetised horses. The results of this study, performed in clinical cases, demonstrated that there was a positive linear relationship between tidal volume measurements obtained with spirometry and impedance changes measured by EIT within each subject and this individual relationship could be used to estimate tidal volume that showed acceptable agreement with a measured tidal volume in each horse. Thus, EIT can be used to observe changes in tidal volume by the means of impedance changes. However, absolute measurement of tidal volume is only possible after establishment of the individual relationship. Abstract This study explores the application of electric impedance tomography (EIT) to estimate tidal volume (VT) by measuring impedance change per breath (∆Zbreath). Seventeen healthy horses were anaesthetised and mechanically ventilated for elective procedures requiring dorsal recumbency. Spirometric VT (VTSPIRO) and ∆Zbreath were recorded periodically; up to six times throughout anaesthesia. Part 1 assessed these variables at incremental delivered VT of 10, 12 and 15 mL/kg. Part 2 estimated VT (VTEIT) in litres from ∆Zbreath at three additional measurement points using a line of best fit obtained from Part 1. During part 2, VT was adjusted to maintain end-tidal carbon dioxide between 45–55 mmHg. Linear regression determined the correlation between VTSPIRO and ∆Zbreath (part 1). Estimated VTEIT was assessed for agreement with measured VTSPIRO using Bland Altman analysis (part 2). Marked variability in slope and intercepts was observed across horses. Strong positive correlation between ∆Zbreath and VTSPIRO was found in each horse (R2 0.9–0.99). The agreement between VTEIT and VTSPIRO was good with bias (LOA) of 0.26 (−0.36–0.88) L. These results suggest that, in anaesthetised horses, EIT can be used to monitor and estimate VT after establishing the individual relationship between these variables.
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17
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Sang L, Zhao Z, Lin Z, Liu X, Zhong N, Li Y. A narrative review of electrical impedance tomography in lung diseases with flow limitation and hyperinflation: methodologies and applications. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1688. [PMID: 33490200 PMCID: PMC7812189 DOI: 10.21037/atm-20-4984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Electrical impedance tomography (EIT) is a functional radiation-free imaging technique that measures regional lung ventilation distribution by calculating the impedance changes in the corresponding regions. The aim of the present review was to summarize the current literature concerning the methodologies and applications of EIT in lung diseases with flow limitation and hyperinflation. PubMed was searched up to May 2020 to identify studies investigating the use of EIT in patients with asthma, bronchiectasis, bronchitis, bronchiolitis, chronic obstructive pulmonary disease, and cystic fibrosis. The extracted data included study design, EIT methodologies, interventions, validation and comparators, population characteristics, and key findings. Of the 44 included studies, seven were related to simulation, animal experimentation, or reconstruction algorithm development with evaluation on patients; 27 studies had the primary objective of validating EIT technique and measures including regional ventilation distribution, regional EIT-spirometry parameters, end-expiratory lung impedance, and regional time constants; and 10 studies had the primary objective of applying EIT to monitor the response to therapeutic interventions, including various ventilation supports, patient repositioning, and airway suctioning. In pediatric and adult patients, EIT has been successfully validated for assessing spatial and temporal ventilation distribution, measuring changes in lung volume and flow, and studying regional respiratory mechanics. EIT has also demonstrated potential as an alternative or supplement to well-established measurement modalities (e.g., conventional pulmonary function testing) to monitor the progression of obstructive lung diseases, although the existing literature lacks prediction values as references and lacks clinical outcome evidence.
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Affiliation(s)
- Ling Sang
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Zhimin Lin
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Xiaoqing Liu
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Nanshan Zhong
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Yimin Li
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
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18
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Zhao Z, Chang MY, Frerichs I, Zhang JH, Chang HT, Gow CH, Möller K. Regional air trapping in acute exacerbation of obstructive lung diseases measured with electrical impedance tomography: a feasibility study. Minerva Anestesiol 2019; 86:172-180. [PMID: 31808658 DOI: 10.23736/s0375-9393.19.13732-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Since bronchial abnormalities often exhibit spatial non-uniformity which may be not correctly assessed by conventional global lung function measures, regional information may help to characterize the disease progress. We hypothesized that regional air trapping during mechanical ventilation could be characterized by regional end-expiratory flow (EEF) derived from electrical impedance tomography (EIT). METHODS Twenty-five patients suffering from chronic obstructive pulmonary disease (COPD grade 3 or 4) or severe asthma with acute exacerbation were examined prospectively. Patients were ventilated under assist-control mode. EIT measurements were conducted before and one hour after inhaled combined corticosteroid and long-acting β2 agonist, on two consecutive days. Regional EEF was calculated as derivative of relative impedance for every image pixel in the lung regions. The results were normalized to global flow values measured by the ventilator. RESULTS Regional and global EEF were highly correlated (P<0.00001) and regional effects of medication and disease progression were visible in the regional EEF maps. The sums of regional EEF in lung regions were 3.8 [2.0, 5.1] and 3.6 [1.9, 4.5] L/min in COPD patients before and after medication (median [lower, upper quartiles]; P=0.37). The corresponding values in asthma patients were 3.0 [2.5, 4.2] and 2.2 [1.7, 3.2] L/min (P<0.05). Histograms of regional EEF showed high spatial heterogeneity of EEF before medication. After one day of treatment, the histograms exhibited less heterogeneous and a decrease in EEF level. CONCLUSIONS Regional EEF characterizes air trapping and intrinsic PEEP, which could provide diagnostic information for monitoring the disease progress during treatment.
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Affiliation(s)
- Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Mei-Yun Chang
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Center of Schleswig-Holstein Campus, Kiel, Germany
| | - Jia-Hao Zhang
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Hou-Tai Chang
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Chien-Hung Gow
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan - .,Department of Healthcare Information and Management, Ming-Chuan University, Taoyuan, Taiwan
| | - Knut Möller
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
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19
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Barrett NA, Hart N, Camporota L. Assessment of Work of Breathing in Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Disease. COPD 2019; 16:418-428. [PMID: 31694406 DOI: 10.1080/15412555.2019.1681390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The assessment of the work of breathing (WOB) of patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) is difficult, particularly when the patient first presents with acute hypercapnia and respiratory acidosis. Acute exacerbations of COPD patients are in significant respiratory distress and noninvasive measurements of WOB are easier for the patient to tolerate. Given the interest in using alternative therapies to noninvasive ventilation, such as high flow nasal oxygen therapy or extracorporeal carbon dioxide removal, understanding the physiological changes are key and this includes assessment of WOB. This narrative review considers the role of three different methods of assessing WOB in patients with acute exacerbations of COPD. Esophageal pressure is a very well validated measure of WOB, however the ability of patients with acute exacerbations of COPD to tolerate esophageal tubes is poor. Noninvasive alternative measurements include parasternal electromyography (EMG) and electrical impedance tomography (EIT). EMG is easily applied and is a well validated measure of neural drive but is more likely to be degraded by the electrical environment in intensive care or high dependency. EIT is less well validated as a tool for WOB in COPD but extremely well tolerated by patients. Each of the different methods assess WOB in a different way and have different advantages and disadvantages. For research into therapies treating acute exacerbations of COPD, combinations of EIT, EMG and esophageal pressure are likely to be better than only one of these.
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Affiliation(s)
- N A Barrett
- Centre for Human & Applied Physiological Sciences (CHAPS), School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.,Department of Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - N Hart
- Lane Fox Respiratory Unit, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - L Camporota
- Centre for Human & Applied Physiological Sciences (CHAPS), School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom.,Department of Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
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20
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Electrical Impedance Tomography for Cardio-Pulmonary Monitoring. J Clin Med 2019; 8:jcm8081176. [PMID: 31394721 PMCID: PMC6722958 DOI: 10.3390/jcm8081176] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/05/2019] [Accepted: 08/06/2019] [Indexed: 12/14/2022] Open
Abstract
Electrical impedance tomography (EIT) is a bedside monitoring tool that noninvasively visualizes local ventilation and arguably lung perfusion distribution. This article reviews and discusses both methodological and clinical aspects of thoracic EIT. Initially, investigators addressed the validation of EIT to measure regional ventilation. Current studies focus mainly on its clinical applications to quantify lung collapse, tidal recruitment, and lung overdistension to titrate positive end-expiratory pressure (PEEP) and tidal volume. In addition, EIT may help to detect pneumothorax. Recent studies evaluated EIT as a tool to measure regional lung perfusion. Indicator-free EIT measurements might be sufficient to continuously measure cardiac stroke volume. The use of a contrast agent such as saline might be required to assess regional lung perfusion. As a result, EIT-based monitoring of regional ventilation and lung perfusion may visualize local ventilation and perfusion matching, which can be helpful in the treatment of patients with acute respiratory distress syndrome (ARDS).
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21
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Grychtol B, Schramel JP, Braun F, Riedel T, Auer U, Mosing M, Braun C, Waldmann AD, Böhm SH, Adler A. Thoracic EIT in 3D: experiences and recommendations. Physiol Meas 2019; 40:074006. [PMID: 31189141 DOI: 10.1088/1361-6579/ab291d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE In EIT applications to the thorax, a single electrode plane has typically been used to reconstruct a transverse 2D 'slice'. However, such images can be misleading as EIT is sensitive to contrasts above and below the electrode plane, and ventilation and aeration inhomogeneities can be distributed in complex ways. Using two (or more) electrode planes, 3D EIT images may be reconstructed, but 3D reconstructions are currently little used in thoracic EIT. In this paper, we investigate an incremental pathway towards 3D EIT reconstructions, using two electrode planes to calculate improved transverse slices as an intermediate step. We recommend a specific placement of electrode planes, and further demonstrate the feasibility of multi-slice reconstruction in two species. APPROACH Simulations of the forward and reconstructed sensitivities were analysed for two electrode planes using a 'square' pattern of electrode placement as a function of two variables: the stimulation and measurement 'skip', and the electrode plane separation. Next, single- versus two-plane measurements were compared in a horse and in human volunteers. We further show the feasibility of 3D reconstructions by reconstructing multiple transverse and, unusually, frontal slices during ventilation. MAIN RESULTS Using two electrode planes leads to a reduced position error and improvement in off-plane contrast rejection. 2D reconstructions from two-plane measurements showed better separation of lungs, as compared to the single plane measurements which tend to push contrasts in the center of the image. 3D reconstructions of the same data show anatomically plausible images, inside as well as outside the volume between the two electrode planes. SIGNIFICANCE Based on the results, we recommend EIT electrode planes separated by less than half of the minimum thoracic dimension with a 'skip 4' pattern and 'square' placement to produce images with good slice selectivity.
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Affiliation(s)
- Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology, Mannheim, Germany. Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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22
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Victor M, Melo J, Roldán R, Nakamura M, Tucci M, Costa E, Amato M, Yoneyama T, Tanaka H. Modelling approach to obtain regional respiratory mechanics using electrical impedance tomography and volume-dependent elastance model. Physiol Meas 2019; 40:045001. [PMID: 30921784 DOI: 10.1088/1361-6579/ab144a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This paper presents a method for breath-by-breath estimation of regional respiratory mechanics without the need for special manoeuvres (such as inspiratory pause or low-flow inflation) using electrical impedance tomography (EIT) associated with pressure/airflow waveforms. APPROACH We developed a method to estimate regional parameters using the regional impedance fraction, by multiplying it by global flow and volume waveforms. A volume-dependent elastance model was used to obtain compliance, resistance, volume-independent (E 1), and volume-dependent (E 2) components. Three swine under invasive mechanical ventilation were used to assess internal consistency and illustrate potential applications of our method. One animal (case 1) was ventilated with a broad range of tidal volumes to compare the consistency between regional and global resistances and compliances. Two other animals (cases 2 and 3) had respiratory compliance decreased, respectively, by overdistension and collapse as quantified by x-ray computed tomography. MAIN RESULTS In case 1, derived global estimates obtained from the independent regional estimates were strongly associated with direct measurements of global mechanics (correlation coefficients of 0.9976 and 0.9981 for compliances and resistances, respectively), suggesting consistency of our modelling. In cases 2 and 3, the development of lung overdistension and collapse over time was captured by regional estimates. CONCLUSIONS Using EIT and pressure/airflow waveforms, regional respiratory parameters can be obtained cycle-by-cycle, refining lung function monitoring. SIGNIFICANCE The method allows real-time monitoring of regional parameters and their trends over time, which might be helpful to differentiate deterioration in lung compliance due to overdistension or collapse.
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Affiliation(s)
- M Victor
- Electronics Engineering Department, Aeronautics Institute of Technology, São Paulo, Brazil
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23
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Ngo C, Spagnesi S, Munoz C, Lehmann S, Vollmer T, Misgeld B, Leonhardt S. Assessing regional lung mechanics by combining electrical impedance tomography and forced oscillation technique. ACTA ACUST UNITED AC 2019; 63:673-681. [PMID: 28850542 DOI: 10.1515/bmt-2016-0196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 07/17/2017] [Indexed: 11/15/2022]
Abstract
There is a lack of noninvasive pulmonary function tests which can assess regional information of the lungs. Electrical impedance tomography (EIT) is a radiation-free, non-invasive real-time imaging that provides regional information of ventilation volume regarding the measurement of electrical impedance distribution. Forced oscillation technique (FOT) is a pulmonary function test which is based on the measurement of respiratory mechanical impedance over a frequency range. In this article, we introduce a new measurement approach by combining FOT and EIT, named the oscillatory electrical impedance tomography (oEIT). Our oEIT measurement system consists of a valve-based FOT device, an EIT device, pressure and flow sensors, and a computer fusing the data streams. Measurements were performed on five healthy volunteers at the frequencies 3, 4, 5, 6, 7, 8, 10, 15, and 20 Hz. The measurements suggest that the combination of FOT and EIT is a promising approach. High frequency responses are visible in the derivative of the global impedance index ΔZeit(t,fos). $\Delta {Z_{{\text{eit}}}}(t,{f_{{\text{os}}}}).$ The oEIT signals consist of three main components: forced oscillation, spontaneous breathing, and heart activity. The amplitude of the oscillation component decreases with increasing frequency. The band-pass filtered oEIT signal might be a new tool in regional lung function diagnostics, since local responses to high frequency perturbation could be distinguished between different lung regions.
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Affiliation(s)
- Chuong Ngo
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Sarah Spagnesi
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Carlos Munoz
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Sylvia Lehmann
- Department of Pediatric Pulmonology, University Hospital RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Thomas Vollmer
- Philips GmbH Innovative Technologies Aachen, Pauwelsstr. 17, 52074 Aachen, Germany
| | - Berno Misgeld
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
| | - Steffen Leonhardt
- Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstr. 20, 52074 Aachen, Germany
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Mosing M, Waldmann AD, Raisis A, Böhm SH, Drynan E, Wilson K. Monitoring of tidal ventilation by electrical impedance tomography in anaesthetised horses. Equine Vet J 2018; 51:222-226. [PMID: 30035329 DOI: 10.1111/evj.12998] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/13/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) is a method to measure regional impedance changes within the thorax. The total tidal impedance variation has been used to measure changes in tidal volumes in pigs, dogs and men. OBJECTIVES To assess the ability of EIT to quantify changes in tidal volume in anaesthetised mechanically ventilated horses. STUDY DESIGN In vivo experimental study. METHODS Six horses (mean ± s.d.: age 11.5 ± 7.5 years and body weight 491 ± 40 kg) were anaesthetised using isoflurane in oxygen. The lungs were mechanically ventilated using a volume-controlled mode. With an end-tidal carbon dioxide tension in the physiological range, and a set tidal volume (VTvent ) of 11-16 mL/kg (baseline volume), EIT data and VT measured by conventional spirometry were collected over 1 min. Thereafter, VTvent was changed in 1 L steps until reaching 10 L. After, VTvent was reduced to 1 L below the baseline volume and then further reduced in 1 L steps until 4 L. On each VT step data were recorded for 1 min after allowing 1 min of stabilisation. Impedance changes within the predefined two lung regions of interest (EITROI ) and the whole image (EITthorax ) were calculated. Linear regression analysis was used to assess the relationship between spirometry data and EITROI and EITthorax for individual horses and pooled data. RESULTS Both EITROI and EITthorax significantly predicted spirometry data for individual horses with R2 ranging from 0.937 to 0.999 and from 0.954 to 0.997 respectively. This was similar for pooled data from all six horses with EITROI (R2 = 0.799; P<0.001) and EITthorax (R2 = 0.841; P<0.001). MAIN LIMITATIONS The method was only tested in healthy mechanically ventilated horses. CONCLUSIONS The EIT can be used to quantify changes in tidal volume.
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Affiliation(s)
- M Mosing
- College of Veterinary Medicine, Murdoch University, Perth, Australia
| | - A D Waldmann
- Swisstom, Landquart, Switzerland.,Department of Pneumology and Critical Care Medicine, Witten/Herdecke University Hospital, Cologne, Germany
| | - A Raisis
- College of Veterinary Medicine, Murdoch University, Perth, Australia
| | - S H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - E Drynan
- College of Veterinary Medicine, Murdoch University, Perth, Australia
| | - K Wilson
- College of Veterinary Medicine, Murdoch University, Perth, Australia
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25
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Ngo C, Dippel F, Tenbrock K, Leonhardt S, Lehmann S. Flow-volume loops measured with electrical impedance tomography in pediatric patients with asthma. Pediatr Pulmonol 2018; 53:636-644. [PMID: 29405616 DOI: 10.1002/ppul.23962] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/15/2018] [Indexed: 12/16/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) provides information on global and regional ventilation during tidal breathing and mechanical ventilation. During forced expiration maneuvers, the linearity of EIT and spirometric data has been documented in healthy persons. The present study investigates the potential diagnostic use of EIT in pediatric patients with asthma. METHODS EIT and spirometry were performed in 58 children with asthma (average age ± SD: 11.86 ± 3.13 years), and 58 healthy controls (average age ± SD: 12.12 ± 2.9 years). The correlation between EIT data and simultaneously acquired spirometric data were tested for FEV1, FEV0.5 , MEF75 , MEF50 , and MEF25 . Binary classification tests were performed for the EIT-derived Tiffeneau index FEV1 /FVC and the bronchodilator test index ΔFEV1 . Average flow-volume (FV) loops were generated for patients with pathologic spirometry to demonstrate the feasibility of EIT for graphic diagnosis of asthma. RESULTS Spirometry and global EIT-based FV loops showed a strong correlation (P < 0.001, r > 0.9 in FEV1 and FEV0.5 ). In all criteria, the binary classification tests yielded high specificity (>93%), a high positive predictive value (≥75%) and a high negative predictive value (>80%), while sensitivity was higher in ΔFEV1 (86.67%) and lower in FEV1 /FVC (25% and 35.29%). A typical concave shape of the EIT-derived average FV loops was observed for asthmatic children with improvement after bronchospasmolysis. CONCLUSIONS Global FV loops derived from EIT correlate well with spirometry. Positive bronchospasmolysis can be observed in EIT-derived FV loops. Flow-volume loops originated from EIT have a potential to visualize pulmonary function.
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Affiliation(s)
- Chuong Ngo
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Falk Dippel
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Klaus Tenbrock
- Department of Pediatric Pulmonology, RWTH Aachen University Hospital, Aachen, Germany
| | - Steffen Leonhardt
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Sylvia Lehmann
- Department of Pediatric Pulmonology, RWTH Aachen University Hospital, Aachen, Germany
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26
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Muller PA, Mueller JL, Mellenthin M, Murthy R, Capps M, Wagner BD, Alsaker M, Deterding R, Sagel SD, Hoppe J. Evaluation of surrogate measures of pulmonary function derived from electrical impedance tomography data in children with cystic fibrosis. Physiol Meas 2018; 39:045008. [PMID: 29565263 DOI: 10.1088/1361-6579/aab8c4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Lung function monitoring by spirometry plays a critical role in the clinical care of pediatric cystic fibrosis (CF) patients, but many young children are unable to perform spirometry, and the outputs are often normal even in the presence of lung disease. Measures derived from electrical impedance tomography (EIT) images were studied for their utility as potential surrogates for spirometry in CF patients and to assess response to intravenous antibiotic treatment for acute pulmonary exacerbations (PEx) in a subset of patients. APPROACH EIT data were collected on 35 subjects (21 with CF, 14 healthy controls, 8 CF patients pre- and post-treatment for an acute PEx) ages 2 to 20 years during tidal breathing and also concurrently with spirometry on subjects over age 8. EIT-derived measures of FEV1, FVC, and FEV1/FVC were computed globally and regionally from dynamic EIT images. MAIN RESULTS Global EIT-derived FEV1/FVC showed good correlation with spirometry FEV1/FVC values (r = 0.54, p = 0.01), and were able to distinguish between the groups (p = 0.01). Lung heterogeneity was assessed through the spatial coefficient of variation (CV) of EIT difference images between key time points, and the CVs for EIT-derived FEV1 and FVC showed significant correlation with the CV for tidal breathing (r = 0.47, p = 0.01 and r = 0.50, p = 0.01, respectively). Global EIT-derived FEV1/FVC was better able to distinguish between groups than spirometry FEV1 (F-values 776.5 and 146.3, respectively, p < 0.01.) The same held true for the CVs for EIT-derived FEV1, FVC, and tidal breathing (F-values 215.93, 193.89, 204.57, respectively, p < 0.01). SIGNIFICANCE The strong correlation between the CVs for tidal breathing, FEV1, and FVC, and the statistically significant ability of CV for tidal breathing to distinguish between healthy subjects and CF patients, and between the studied CF disease states suggests that the CV may be useful for measuring the extent and severity of structural lung disease.
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Affiliation(s)
- Peter A Muller
- Department of Mathematics & Statistics, Villanova University, PA, United States of America. was at Department of Mathematics, Colorado State University, CO, United States of America
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27
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da Silva Ramos FJ, Hovnanian A, Souza R, Azevedo LCP, Amato MBP, Costa ELV. Estimation of Stroke Volume and Stroke Volume Changes by Electrical Impedance Tomography. Anesth Analg 2018; 126:102-110. [PMID: 28742775 DOI: 10.1213/ane.0000000000002271] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) is a noninvasive imaging method that identifies changes in air and blood volume based on thoracic impedance changes. Recently, there has been growing interest in EIT to measure stroke volume (SV). The objectives of this study are as follows: (1) to evaluate the ability of systolic impedance variations (ΔZsys) to track changes in SV in relation to a baseline condition; (2) to assess the relationship of ΔZsys and SV in experimental subjects; and (3) to identify the influence of body dimensions on the relationship between ΔZsys and SV. METHODS Twelve Agroceres pigs were instrumented with transpulmonary thermodilution catheter and EIT and were mechanically ventilated in a random order using different settings of tidal volume (VT) and positive end-expiratory pressure (PEEP): VT 10 mL·kg and PEEP 10 cm H2O, VT 10 mL·kg and PEEP 5 cm H2O, VT 6 mL·kg and PEEP 10 cm H2O, and VT 6 mL·kg and PEEP 5 cm H2O. After baseline data collection, subjects were submitted to hemorrhagic shock and successive fluid challenges. RESULTS A total of 204 paired measurements of SV and ΔZsys were obtained. The 4-quadrant plot showed acceptable trending ability with a concordance rate of 91.2%. Changes in ΔZsys after fluid challenges presented an area under the curve of 0.83 (95% confidence interval, 0.74-0.92) to evaluate SV changes. Conversely, the linear association between ΔZsys and SV was poor, with R from linear mixed model of 0.35. Adding information on body dimensions improved the linear association between ΔZsys and SV up to R from linear mixed model of 0.85. CONCLUSIONS EIT showed good trending ability and is a promising hemodynamic monitoring tool. Measurements of absolute SV require that body dimensions be taken into account.
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Affiliation(s)
- Fernando José da Silva Ramos
- From the Department of Intensive Care and Anesthesiology Research Laboratory, Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil
| | - André Hovnanian
- From the Department of Intensive Care and Anesthesiology Research Laboratory, Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil.,Respiratory Intensive Care Unit, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Rogério Souza
- Respiratory Intensive Care Unit, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Luciano C P Azevedo
- From the Department of Intensive Care and Anesthesiology Research Laboratory, Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Marcelo B P Amato
- Respiratory Intensive Care Unit, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Eduardo L V Costa
- From the Department of Intensive Care and Anesthesiology Research Laboratory, Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil.,Respiratory Intensive Care Unit, University of São Paulo School of Medicine, São Paulo, Brazil
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28
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Zhao Z, Peng SY, Chang MY, Hsu YL, Frerichs I, Chang HT, Möller K. Spontaneous breathing trials after prolonged mechanical ventilation monitored by electrical impedance tomography: an observational study. Acta Anaesthesiol Scand 2017; 61:1166-1175. [PMID: 28832898 DOI: 10.1111/aas.12959] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/12/2017] [Accepted: 07/18/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND The study objective was to examine the correlation between regional ventilation distribution measured with electrical impedance tomography (EIT) and weaning outcomes during spontaneous breathing trial (SBT). METHODS Fifteen patients received 100% automatic tube compensation (ATC) during the first and 70% during the second hour. Another 15 patients received external continuous positive airway pressure (CPAP) of 5 and 7.5 cmH2 O during the first and second hours, respectively. Regional ventilation distributions were monitored with EIT. RESULTS Tidal volume and tidal variation of impedance correlated significantly during assist-control ventilation and ATC in all patients (r2 = 0.80 ± 0.18, P < 0.001). Higher support levels resulted in similar ventilation distribution and tidal volume, but higher end-expiratory lung impedance (EELI) (P < 0.05). Analysis of regional intratidal gas distribution revealed a redistribution of ventilation towards dorsal regions with lower support level in 13 of 30 patients. These patients had a higher weaning success rate (only 1 of 13 patients failed). Eight of 17 other patient failed (P < 0.05). The number of SBT days needed for weaning was significantly lower in the former group of 13 patients (13.1 ± 4.0 vs. 20.9 ± 11.2 days, P < 0.05). CONCLUSIONS Regional ventilation distribution patterns during inspiration were associated with weaning outcomes, and they may be used to predict the success of extubation.
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Affiliation(s)
- Z. Zhao
- Institute of Technical Medicine; Furtwangen University; Villingen-Schwenningen Germany
- Department of Biomedical Engineering; Fourth Military Medical University; Xi'an China
| | - S.-Y. Peng
- Division of Pulmonary Medicine; Department of Internal Medicine; Far Eastern Memorial Hospital; New Taipei City Taiwan
| | - M.-Y. Chang
- Division of Pulmonary Medicine; Department of Internal Medicine; Far Eastern Memorial Hospital; New Taipei City Taiwan
| | - Y.-L. Hsu
- Division of Pulmonary Medicine; Department of Internal Medicine; Far Eastern Memorial Hospital; New Taipei City Taiwan
| | - I. Frerichs
- Department of Anesthesiology and Intensive Care Medicine; University Medical Center of Schleswig-Holstein Campus Kiel; Kiel Germany
| | - H.-T. Chang
- Medical Intensive Care Unit; Department of Critical Care Medicine; Far Eastern Memorial Hospital; New Taipei City Taiwan
| | - K. Möller
- Institute of Technical Medicine; Furtwangen University; Villingen-Schwenningen Germany
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29
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Ngo C, Leonhardt S, Zhang T, Lüken M, Misgeld B, Vollmer T, Tenbrock K, Lehmann S. Linearity of electrical impedance tomography during maximum effort breathing and forced expiration maneuvers. Physiol Meas 2016; 38:77-86. [PMID: 28004642 DOI: 10.1088/1361-6579/38/1/77] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Electrical impedance tomography (EIT) provides global and regional information about ventilation by means of relative changes in electrical impedance measured with electrodes placed around the thorax. In combination with lung function tests, e.g. spirometry and body plethysmography, regional information about lung ventilation can be achieved. Impedance changes strictly correlate with lung volume during tidal breathing and mechanical ventilation. Initial studies presumed a correlation also during forced expiration maneuvers. To quantify the validity of this correlation in extreme lung volume changes during forced breathing, a measurement system was set up and applied on seven lung-healthy volunteers. Simultaneous measurements of changes in lung volume using EIT imaging and pneumotachography were obtained with different breathing patterns. Data was divided into a synchronizing phase (spontaneous breathing) and a test phase (maximum effort breathing and forced maneuvers). The EIT impedance changes correlate strictly with spirometric data during slow breathing with increasing and maximum effort ([Formula: see text]) and during forced expiration maneuvers ([Formula: see text]). Strong correlations in spirometric volume parameters [Formula: see text] ([Formula: see text]), [Formula: see text]/FVC ([Formula: see text]), and flow parameters PEF, [Formula: see text], [Formula: see text], [Formula: see text] ([Formula: see text]) were observed. According to the linearity during forced expiration maneuvers, EIT can be used during pulmonary function testing in combination with spirometry for visualisation of regional lung ventilation.
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Affiliation(s)
- Chuong Ngo
- Philips Chair of Medical Information Technology, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
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30
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Lehmann S, Leonhardt S, Ngo C, Bergmann L, Ayed I, Schrading S, Tenbrock K. Global and regional lung function in cystic fibrosis measured by electrical impedance tomography. Pediatr Pulmonol 2016; 51:1191-1199. [PMID: 27127915 DOI: 10.1002/ppul.23444] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 02/08/2016] [Accepted: 03/05/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) delivers information about global and regional ventilation. Linearity of EIT during tidal breathing is known. We investigated the feasibility of EIT during lung function tests in pediatric patients with cystic fibrosis (CF) and healthy controls. METHODS Eleven CF patients and 11 age-matched controls underwent spirometry and simultaneous EIT. Global EIT results were scaled to spirometric forced vital capacity (FVC). Subsequently, global and regional "EIT-spirometry" was calculated and correlated with clinical findings, radiology, and lung function results before and after bronchospasmolysis (BSL). RESULTS Spirometry and global EIT results correlated essentially (r2 = 0.71-1.0, P < 0.001). While lung function results were comparable for both groups, EIT demonstrated inhomogeneous ventilation and individual changes after BSL. CONCLUSIONS EIT changes during forced expiration correlate with lung function parameters, clinical findings, and radiology. Regional analysis of EIT illustrates regional lung function and visualizes individual therapeutic effects. Pediatr Pulmonol. 2016;51:1191-1199. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sylvia Lehmann
- Division of Pediatric Pulmonology, Department of Pediatrics, University Hospital RWTH Aachen, Pauwelsstrasse 30, 52074, Aachen, Germany.
| | - Steffen Leonhardt
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Chuong Ngo
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Lukas Bergmann
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Ines Ayed
- Philips Chair for Medical Information Technology, RWTH Aachen, Aachen, Germany
| | - Simone Schrading
- Department of Radiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Klaus Tenbrock
- Division of Pediatric Pulmonology, Department of Pediatrics, University Hospital RWTH Aachen, Pauwelsstrasse 30, 52074, Aachen, Germany
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31
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Milesi I, Tingay DG, Zannin E, Bianco F, Tagliabue P, Mosca F, Lavizzari A, Ventura ML, Zonneveld CE, Perkins EJ, Black D, Sourial M, Dellacá RL. Intratracheal atomized surfactant provides similar outcomes as bolus surfactant in preterm lambs with respiratory distress syndrome. Pediatr Res 2016; 80:92-100. [PMID: 26954481 DOI: 10.1038/pr.2016.39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/21/2015] [Indexed: 11/09/2022]
Abstract
BACKGROUND Aerosolization of exogenous surfactant remains a challenge. This study is aimed to evaluate the efficacy of atomized poractant alfa (Curosurf) administered with a novel atomizer in preterm lambs with respiratory distress syndrome. METHODS Twenty anaesthetized lambs, 127 ± 1 d gestational age, (mean ± SD) were instrumented before birth and randomized to receive either (i) positive pressure ventilation without surfactant (Control group), (ii) 200 mg/kg of bolus instilled surfactant (Bolus group) at 10 min of life or (iii) 200 mg/kg of atomized surfactant (Atomizer group) over 60 min from 10 min of life. All lambs were ventilated for 180 min with a standardized protocol. Lung mechanics, regional lung compliance (electrical impedance tomography), and carotid blood flow (CBF) were measured with arterial blood gas analysis. RESULTS Dynamic compliance and oxygenation responses were similar in the Bolus and Atomizer groups, and both better than Control by 180 min (all P < 0.05; two-way ANOVA). Both surfactant groups demonstrated more homogeneous regional lung compliance throughout the study period. There were no differences in CBFConclusion:In a preterm lamb model, atomized surfactant resulted in similar gas exchange and mechanics as bolus administration. This study suggests evaluation of supraglottic atomization with this system when noninvasive support is warranted.
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Affiliation(s)
- Ilaria Milesi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milano, Italy
| | - David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia.,Neonatology, The Royal Children's Hospital, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Emanuela Zannin
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milano, Italy
| | - Federico Bianco
- Research and Development Department, Chiesi Farmaceutici SpA, Parma, Italy
| | | | - Fabio Mosca
- NICU, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico-Università degli Studi di Milano
| | - Anna Lavizzari
- NICU, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico-Università degli Studi di Milano
| | | | - C Elroy Zonneveld
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Don Black
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Magdy Sourial
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Raffaele L Dellacá
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano University, Milano, Italy
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Liu S, Tan L, Möller K, Frerichs I, Yu T, Liu L, Huang Y, Guo F, Xu J, Yang Y, Qiu H, Zhao Z. Identification of regional overdistension, recruitment and cyclic alveolar collapse with electrical impedance tomography in an experimental ARDS model. Crit Care 2016; 20:119. [PMID: 27142073 PMCID: PMC4855824 DOI: 10.1186/s13054-016-1300-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 04/19/2016] [Indexed: 11/21/2022] Open
Abstract
Background Information on regional ventilation distribution in mechanically ventilated patients is important to develop lung protective ventilation strategies. In the present prospective animal study, we introduce an electrical impedance tomography (EIT)-based method to classify lungs into normally ventilated, overinflated, tidally recruited/derecruited and recruited regions. Methods Acute respiratory distress syndrome (ARDS) was introduced with repeated bronchoalveolar lavage in ten healthy male pigs until the ratio of arterial partial pressure of oxygen and fraction of inspired oxygen (PaO2/FiO2) decreased to less than 100 mmHg and remained stable for 30 minutes. Stepwise positive end-expiratory pressure (PEEP) increments were performed from 0 cmH2O to 30 cmH2O with 3 cmH2O increase every 5 minutes. Respiratory system compliance (Crs), blood gases and hemodynamics were measured at the same time. Lung regions at end-expiration and during tidal breathing were identified in EIT images. Results Overinflated regions contain air at end-expiration but they are not or are only minimally ventilated. Recruited regions compared to reference PEEP level contain air at end-expiration of arbitrary PEEP level but not at that of reference PEEP level. Tidally recruited/derecruited regions are not represented in lung regions at end-expiration but are ventilated during tidal breathing. The results coincided with measurements of blood gases. The coefficient for correlation between the number of recruited pixels and PaO2/FiO2 was 0.89 ± 0.12 (p = 0.02). Conclusion The proposed novel EIT-based method provides information on overinflation, recruitment and cyclic alveolar collapse at the bedside, which may improve the ventilation strategies used.
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Affiliation(s)
- Songqiao Liu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Li Tan
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Knut Möller
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle Straße 17, 78054, VS-Schwenningen, Germany
| | - Inez Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center of Schleswig-Holstein Campus Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany
| | - Tao Yu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Ling Liu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Yingzi Huang
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Fengmei Guo
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Jingyuan Xu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Yi Yang
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China
| | - Haibo Qiu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu Province, 210009, China.
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle Straße 17, 78054, VS-Schwenningen, Germany
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Yun L, He HW, Möller K, Frerichs I, Liu D, Zhao Z. Assessment of Lung Recruitment by Electrical Impedance Tomography and Oxygenation in ARDS Patients. Medicine (Baltimore) 2016; 95:e3820. [PMID: 27258527 PMCID: PMC4900735 DOI: 10.1097/md.0000000000003820] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
We hypothesized that not all patients with appreciably recruited lung tissue during a recruitment maneuver (RM) show significant improvement of oxygenation. In the present study, we combined electrical impedance tomography (EIT) with oxygenation measurements to examine the discrepancies of lung ventilation and perfusion versus oxygenation after RM.A 2-minute RM (20 cm H2O positive end-expiratory pressure [PEEP] + 20 cm H2O pressure control) was prospectively conducted in 20 acute respiratory distress syndrome patients from January 2014 to December 2014. A decremental PEEP trial was performed to select the PEEP level after RM. A positive response to RM was identified as PaO2 + PaCO2 ≥400 mm Hg. Relative differences in the distribution of ventilation and perfusion in the most dependent region of interest (ROI4) were monitored with EIT and denoted as the ventilation-perfusion index.Ten patients were found to be responders and 10 patients to be nonresponders. No significant difference in baseline PaO2/FiO2 was observed between nonresponders and responders. A significantly higher PaO2/FiO2 ratio during RM and higher PEEP set after PEEP titration were recorded in responders. In both responders and nonresponders, the proportion of ventilation distributed in ROI4 compared with the global value was lower than the cardiac-related activity before RM, but this situation was reversed after RM (P < 0.01 in each group). Six out of 10 nonresponders exhibited a remarkable increase in ventilation in ROI4. A significant difference in the relative ventilation-perfusion index was found between the patients with remarkable and insufficient lung tissue reopening in the nonresponder group (P < 0.01).A discrepancy between lung tissue reopening and oxygenation improvement after RM was observed. EIT has the potential to evaluate the efficacy of RM by combining oxygenation measurements.
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Affiliation(s)
- Long Yun
- From the Department of Critical Care (YL, H-wH, DL), Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China; Institute of Technical Medicine (KM, ZZ), Furtwangen University, Villingen-Schwenningen; and Department of Anesthesiology and Intensive Care Medicine (IF), University Medical Center of Schleswig-Holstein Campus, Kiel, Germany
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Long Y, Liu DW, He HW, Zhao ZQ. Positive End-expiratory Pressure Titration after Alveolar Recruitment Directed by Electrical Impedance Tomography. Chin Med J (Engl) 2016; 128:1421-7. [PMID: 26021494 PMCID: PMC4733776 DOI: 10.4103/0366-6999.157626] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Electrical impedance tomography (EIT) is a real-time bedside monitoring tool, which can reflect dynamic regional lung ventilation. The aim of the present study was to monitor regional gas distribution in patients with acute respiratory distress syndrome (ARDS) during positive-end-expiratory pressure (PEEP) titration using EIT. Methods: Eighteen ARDS patients under mechanical ventilation in Department of Critical Care Medicine of Peking Union Medical College Hospital from January to April in 2014 were included in this prospective observational study. After recruitment maneuvers (RMs), decremental PEEP titration was performed from 20 cmH2O to 5 cmH2O in steps of 3 cmH2O every 5–10 min. Regional over-distension and recruitment were monitored with EIT. Results: After RMs, patient with arterial blood oxygen partial pressure (PaO2) + carbon dioxide partial pressure (PaCO2) >400 mmHg with 100% of fractional inspired oxygen concentration were defined as RM responders. Thirteen ARDS patients was diagnosed as responders whose PaO2 + PaCO2 were higher than nonresponders (419 ± 44 mmHg vs. 170 ± 73 mmHg, P < 0.0001). In responders, PEEP mainly increased recruited pixels in dependent regions and over-distended pixels in nondependent regions. PEEP alleviated global inhomogeneity of tidal volume and end-expiratory lung volume. PEEP levels without significant alveolar derecruitment and over-distension were identified individually. Conclusions: After RMs, PEEP titration significantly affected regional gas distribution in lung, which could be monitored with EIT. EIT has the potential to optimize PEEP titration.
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Affiliation(s)
| | - Da-Wei Liu
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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Tingay DG, Rajapaksa A, Zonneveld CE, Black D, Perkins EJ, Adler A, Grychtol B, Lavizzari A, Frerichs I, Zahra VA, Davis PG. Spatiotemporal Aeration and Lung Injury Patterns Are Influenced by the First Inflation Strategy at Birth. Am J Respir Cell Mol Biol 2016; 54:263-72. [DOI: 10.1165/rcmb.2015-0127oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Tingay DG, Lavizzari A, Zonneveld CEE, Rajapaksa A, Zannin E, Perkins E, Black D, Sourial M, Dellacà RL, Mosca F, Adler A, Grychtol B, Frerichs I, Davis PG. An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1138-49. [DOI: 10.1152/ajplung.00277.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/17/2015] [Indexed: 01/18/2023] Open
Abstract
A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group ( P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone.
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Affiliation(s)
- David G. Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatology, The Royal Children's Hospital, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Anna Lavizzari
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | | | - Anushi Rajapaksa
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Emanuela Zannin
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Elizabeth Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Don Black
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Magdy Sourial
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Raffaele L. Dellacà
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Fabio Mosca
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | - Andy Adler
- Systems and Computer Engineering, Carleton University, Ottawa, Canada
| | - Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology, Mannheim, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany; and
| | - Peter G. Davis
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia
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Hagman C, Janson C, Malinovschi A, Hedenström H, Emtner M. Measuring breathing patterns and respiratory movements with the respiratory movement measuring instrument. Clin Physiol Funct Imaging 2015; 36:414-20. [DOI: 10.1111/cpf.12302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/04/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Carina Hagman
- Center for Clinical Research Dalarna; Falun Sweden
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research; Uppsala University; Uppsala Sweden
- Department of Neuroscience, Physiotherapy; Uppsala University; Uppsala Sweden
| | - Christer Janson
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research; Uppsala University; Uppsala Sweden
| | - Andrei Malinovschi
- Department of Medical Sciences, Clinical Physiology; Uppsala University; Uppsala Sweden
| | - Hans Hedenström
- Department of Medical Sciences, Clinical Physiology; Uppsala University; Uppsala Sweden
| | - Margareta Emtner
- Department of Medical Sciences, Respiratory, Allergy and Sleep Research; Uppsala University; Uppsala Sweden
- Department of Neuroscience, Physiotherapy; Uppsala University; Uppsala Sweden
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Tingay DG, Polglase GR, Bhatia R, Berry CA, Kopotic RJ, Kopotic CP, Song Y, Szyld E, Jobe AH, Pillow JJ. Pressure-limited sustained inflation vs. gradual tidal inflations for resuscitation in preterm lambs. J Appl Physiol (1985) 2015; 118:890-7. [PMID: 25635005 DOI: 10.1152/japplphysiol.00985.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/26/2015] [Indexed: 01/09/2023] Open
Abstract
Support of the mechanically complex preterm lung needs to facilitate aeration while avoiding ventilation heterogeneities: whether to achieve this gradually or quickly remains unclear. We compared the effect of gradual vs. constant tidal inflations and a pressure-limited sustained inflation (SI) at birth on gas exchange, lung mechanics, gravity-dependent lung volume distribution, and lung injury in 131-day gestation preterm lambs. Lambs were resuscitated with either 1) a 20-s, 40-cmH2O pressure-limited SI (PressSI), 2) a gradual increase in tidal volume (Vt) over 5-min from 3 ml/kg to 7 ml/kg (IncrVt), or 3) 7 ml/kg Vt from birth. All lambs were subsequently ventilated for 15 min with 7 ml/kg Vt with the same end-expiratory pressure. Lung mechanics, gas exchange and spatial distribution of end-expiratory volume (EEV), and tidal ventilation (electrical impedance tomography) were recorded regularly. At 15 min, early mRNA tissue markers of lung injury were assessed. The IncrVt group resulted in greater tissue hysteresivity at 5 min (P = 0.017; two-way ANOVA), higher alveolar-arterial oxygen difference from 10 min (P < 0.01), and least uniform gravity-dependent distribution of EEV. There were no other differences in lung mechanics between groups, and the PressSI and 7 ml/kg Vt groups behaved similarly throughout. EEV was more uniformly distributed, but Vt least so, in the PressSI group. There were no differences in mRNA markers of lung injury. A gradual increase in Vt from birth resulted in less recruitment of the gravity-dependent lung with worse oxygenation. There was no benefit of a SI at birth over mechanical ventilation with 7 ml/kg Vt.
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Affiliation(s)
- David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Clayton, Victoria, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Risha Bhatia
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia; Neonatal Research, The Royal Women's Hospital, Melbourne, Victoria, Australia
| | - Clare A Berry
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia
| | | | | | - Yong Song
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Edgardo Szyld
- Universidad Abierta Interamericana (UAI), Buenos Aires, Argentina; Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Alan H Jobe
- Cincinnati Children's Hospital Medical Centre, Cincinnati, Ohio
| | - J Jane Pillow
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia; School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia;
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LI Y, TESSELAAR E, BORGES JB, BÖHM SH, SJÖBERG F, JANEROT-SJÖBERG B. Hyperoxia affects the regional pulmonary ventilation/perfusion ratio: an electrical impedance tomography study. Acta Anaesthesiol Scand 2014; 58:716-25. [PMID: 24762189 DOI: 10.1111/aas.12323] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND The way in which hyperoxia affects pulmonary ventilation and perfusion is not fully understood. We investigated how an increase in oxygen partial pressure in healthy young volunteers affects pulmonary ventilation and perfusion measured by thoracic electrical impedance tomography (EIT). METHODS Twelve semi-supine healthy male volunteers aged 21-36 years were studied while breathing room air and air-oxygen mixtures (FiO2) that resulted in predetermined transcutaneous oxygen partial pressures (tcPO2) of 20, 40 and 60 kPa. The magnitude of ventilation (ΔZv) and perfusion (ΔZQ)-related changes in cyclic impedance variations, were determined using an EIT prototype equipped with 32 electrodes around the thorax. Regional changes in ventral and dorsal right lung ventilation (V) and perfusion (Q) were estimated, and V/Q ratios calculated. RESULTS There were no significant changes in ΔZv with increasing tcPO2 levels. ΔZQ in the dorsal lung increased with increasing tcPO2 (P = 0.01), whereas no such change was seen in the ventral lung. There was a simultaneous decrease in V/Q ratio in the dorsal region during hyperoxia (P = 0.04). Two subjects did not reach a tcPO2 of 60 kPa despite breathing 100% oxygen. CONCLUSION These results indicate that breathing increased concentrations of oxygen induces pulmonary vasodilatation in the dorsal lung even at small increases in FiO2. Ventilation remains unchanged. Local mismatch of ventilation and perfusion occurs in young healthy men, and the change in ventilation/perfusion ratio can be determined non-invasively by EIT.
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Affiliation(s)
- Y. LI
- Department of Anesthesiology; Shaoxing People's Hospital of Zhejiang University; Shaoxing City China
- Department of Clinical and Experimental Medicine; Linköping University; Linköping Sweden
| | - E. TESSELAAR
- Department of Clinical and Experimental Medicine; Linköping University; Linköping Sweden
| | - J. B. BORGES
- Hedenstierna Laboratory; Department of Surgical Sciences; Section of Anesthesiology & Critical Care; Uppsala University; Uppsala Sweden
- Laboratório de Pneumologia LIM-09; Disciplina de Pneumologia; Heart Institute (Incor); Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo Brazil
| | | | - F. SJÖBERG
- Department of Clinical and Experimental Medicine; Linköping University; Linköping Sweden
- Department of Hand; Plastic Surgery and Intensive Care; Linköping University Hospital; Linköping Sweden
| | - B. JANEROT-SJÖBERG
- Department of Clinical Science; Intervention and Technology; Karolinska Institutet; Stockholm Sweden
- Department of Clinical Physiology; Karolinska University Hospital; Stockholm Sweden
- School of Technology and Health; KTH; Royal Institute of Technology; Stockholm Sweden
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Zhao Z, Frerichs I, Pulletz S, Müller-Lisse U, Möller K. The influence of image reconstruction algorithms on linear thorax EIT image analysis of ventilation. Physiol Meas 2014; 35:1083-93. [DOI: 10.1088/0967-3334/35/6/1083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lung reaeration and reventilation after aspiration of pleural effusions: a study using electrical impedance tomography. Ann Am Thorac Soc 2014; 11:466. [PMID: 24673704 DOI: 10.1513/annalsats.201312-457le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Zhao Z, Pulletz S, Frerichs I, Müller-Lisse U, Möller K. The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome. BMC Res Notes 2014; 7:82. [PMID: 24502320 PMCID: PMC3922336 DOI: 10.1186/1756-0500-7-82] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 02/04/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The electrical impedance tomography (EIT)-based global inhomogeneity (GI) index was introduced to quantify tidal volume distribution within the lung. Up to now, the GI index was evaluated for plausibility but the analysis of how it is influenced by various physiological factors is still missing. The aim of our study was to evaluate the influence of proportion of open lung regions measured by EIT on the GI index. METHODS A constant low-flow inflation maneuver was performed in 18 acute respiratory distress syndrome (ARDS) patients (58 ± 14 years, mean age ± SD) and 8 lung-healthy patients (41 ± 12 years) under controlled mechanical ventilation. EIT raw data were acquired at 25 scans/s and reconstructed offline. Recruited lung regions were identified as those image pixels of the lung regions within the EIT scans where local impedance amplitudes exceeded 10% of the maximum amplitude during the maneuver. A series of GI indices was calculated during mechanical lung inflation, based on the differential images obtained between different time points. Respiratory system elastance (Ers) values were calculated at 10 lung volume levels during low-flow maneuver. RESULTS The GI index decreased during low-flow inflation, while the percentage of open lung regions increased. The values correlated highly in both ARDS (r2 = 0.88 ± 0.08, p < 0.01) and lung-healthy patients (r2 = 0.92 ± 0.05, p < 0.01). Ers and GI index were also significantly correlated in 16 out of 18 ARDS (r2 = 0.84 ± 0.13, p < 0.01) and in 6 out of 8 lung-healthy patients (r2 = 0.84 ± 0.07, p < 0.01). Significant differences were found in GI values between two groups (0.52 ± 0.21 for ARDS and 0.41 ± 0.04 for lung-healthy patients, p < 0.05) as well in Ers values (0.017 ± 0.008 cmH2O/ml for ARDS and 0.009 ± 0.001 cmH2O/ml for lung-healthy patients, p < 0.01). CONCLUSIONS We conclude that the GI index is a reliable measure of ventilation heterogeneity highly correlated with lung recruitability measured with EIT. The GI index may prove to be a useful EIT-based index to guide ventilation therapy.
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Affiliation(s)
- Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle Straße 17, D-78054 VS-Schwenningen, Germany.
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Lung Reaeration and Reventilation after Aspiration of Pleural Effusions. A Study Using Electrical Impedance Tomography. Ann Am Thorac Soc 2014; 11:186-91. [DOI: 10.1513/annalsats.201306-142oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Zhao Z, Müller-Lisse U, Frerichs I, Fischer R, Möller K. Regional airway obstruction in cystic fibrosis determined by electrical impedance tomography in comparison with high resolution CT. Physiol Meas 2013; 34:N107-14. [DOI: 10.1088/0967-3334/34/11/n107] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Zhao Z, Frerichs I, Pulletz S, Müller-Lisse U, Möller K. Does thorax EIT image analysis depend on the image reconstruction method? ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/434/1/012040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Electrical impedance tomography: the holy grail of ventilation and perfusion monitoring? Intensive Care Med 2012; 38:1917-29. [DOI: 10.1007/s00134-012-2684-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/08/2012] [Indexed: 01/08/2023]
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Regional ventilation in cystic fibrosis measured by electrical impedance tomography. J Cyst Fibros 2012; 11:412-8. [DOI: 10.1016/j.jcf.2012.03.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/24/2012] [Accepted: 03/25/2012] [Indexed: 11/20/2022]
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Schramel J, Nagel C, Auer U, Palm F, Aurich C, Moens Y. Distribution of ventilation in pregnant Shetland ponies measured by Electrical Impedance Tomography. Respir Physiol Neurobiol 2012; 180:258-62. [DOI: 10.1016/j.resp.2011.11.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 11/10/2011] [Accepted: 11/30/2011] [Indexed: 10/14/2022]
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GRIVANS C, LUNDIN S, STENQVIST O, LINDGREN S. Positive end-expiratory pressure-induced changes in end-expiratory lung volume measured by spirometry and electric impedance tomography. Acta Anaesthesiol Scand 2011; 55:1068-77. [PMID: 22092203 DOI: 10.1111/j.1399-6576.2011.02511.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2011] [Indexed: 12/30/2022]
Abstract
BACKGROUND A bedside tool for monitoring changes in end-expiratory lung volume (ΔEELV) would be helpful to set optimal positive end-expiratory pressure (PEEP) in acute lung injury/acute respiratory distress syndrome patients. The hypothesis of this study was that the cumulative difference of the inspiratory and expiratory tidal volumes of the first 10 breaths after a PEEP change accurately reflects the change in lung volume following a PEEP alteration. METHODS Changing PEEP induces lung volume changes, which are reflected in differences between inspiratory and expiratory tidal volumes measured by spirometry. By adding these differences with correction for offset, for the first 10 breaths after PEEP change, cumulative tidal volume difference was calculated to estimate ΔEELV(VT) ((i-e)) . This method was evaluated in a lung model and in patients with acute respiratory failure during a PEEP trial. In patients, ΔEELV(VT) ((i-e)) were compared with simultaneously measured changes in lung impedance, by electric impedance tomography (EIT), using calibration vs. tidal volume to estimate changes in ΔEELV(EIT) . RESULTS In the lung model, there was close correlation (R(2) = 0.99) between ΔEELV(VT) ((i-e)) and known lung model volume difference, with a bias of -4 ml and limits of agreement of 42 and -50 ml. In 12 patients, ΔEELV(EIT) was closely correlated to ΔEELV(VT) ((i-e)) (R(2) = 0.92), with mean bias of 50 ml and limits of agreement of 131 and -31 ml. Changes in EELV estimated by EIT (ΔEELV(EIT) ) exceeded measurements by spirometry (ΔEELV(VT) ((i-e)) ), with 15 (±15)%. CONCLUSIONS We conclude that spirometric measurements of inspiratory-expiratory tidal volumes agree well with impedance changes monitored by EIT and can be used bedside to estimate PEEP-induced changes in EELV.
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Affiliation(s)
- C. GRIVANS
- Department of Anaesthesiology and Intensive Care; Institute of Clinical Sciences at Sahlgrenska Academy; University of Gothenburg; Gothenburg; Sweden
| | - S. LUNDIN
- Department of Anaesthesiology and Intensive Care; Institute of Clinical Sciences at Sahlgrenska Academy; University of Gothenburg; Gothenburg; Sweden
| | - O. STENQVIST
- Department of Anaesthesiology and Intensive Care; Institute of Clinical Sciences at Sahlgrenska Academy; University of Gothenburg; Gothenburg; Sweden
| | - S. LINDGREN
- Department of Anaesthesiology and Intensive Care; Institute of Clinical Sciences at Sahlgrenska Academy; University of Gothenburg; Gothenburg; Sweden
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