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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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Brabant O, Karpievitch YV, Gwatimba A, Ditcham W, Ho HY, Raisis A, Mosing M. Thoracic electrical impedance tomography identifies heterogeneity in lungs associated with respiratory disease in cattle. A pilot study. Front Vet Sci 2024; 10:1275013. [PMID: 38239750 PMCID: PMC10795053 DOI: 10.3389/fvets.2023.1275013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/07/2023] [Indexed: 01/22/2024] Open
Abstract
Respiratory disease in cattle is a significant global concern, yet current diagnostic methods are limited, and there is a lack of crush-side tests for detecting active disease. To address this gap, we propose utilizing electrical impedance tomography (EIT), a non-invasive imaging technique that provides real-time visualization of lung ventilation dynamics. The study included adult cattle from farms in Western Australia. The cattle were restrained in a crush. A standardized respiratory scoring system, which combined visual, auscultation, and clinical scores, was conducted by two non-conferring clinicians for each animal. The scores were blinded and averaged. During assessment, an EIT electrode belt was placed around the thorax. EIT recordings of ten suitable breaths were taken for analysis before the cattle were released back to the herd. Based on the combined examination scoring, the cattle were categorized as having healthy or diseased lungs. To allow visual interpretation of each breath and enable the creation of the quartile ventilation ratio (VQR), Flow/Tidal Impedance Variation curves (F/TIV) were generated for each breath. The analysis focused on two EIT variables: The novel VQR over time during inhalation and exhalation and global expiratory impedance (TIVEXP) adjusted by breath length. A mixed effects model was used to compare these variables between healthy and diseased cattle. Ten adult cattle of mixed ages were used in the current analysis. Five cattle were scored as healthy and five as diseased. There was a significant difference in the examination scores between the healthy and diseased group (P = 0.03). A significant difference in VQR during inhalation (P = 0.03) was observed between the healthy and diseased groups. No difference was seen in VQR over time during exhalation (P = 0.3). The TIVEXP was not different between groups (P = 0.36). In this study, EIT was able to detect differences in inhalation mechanics when comparing healthy and diseased cattle as defined via clinical examination, highlighting the clinical utility of EIT.
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Affiliation(s)
- Olivia Brabant
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Yuliya V. Karpievitch
- Wal-yan Respiratory Research Centre, Telethon Kids Institute, Perth, WA, Australia
- School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Alphons Gwatimba
- Wal-yan Respiratory Research Centre, Telethon Kids Institute, Perth, WA, Australia
| | - William Ditcham
- School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Ho Yin Ho
- Wal-yan Respiratory Research Centre, Telethon Kids Institute, Perth, WA, Australia
| | - Anthea Raisis
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Martina Mosing
- Anesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
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3
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Heines SJH, Becher TH, van der Horst ICC, Bergmans DCJJ. Clinical Applicability of Electrical Impedance Tomography in Patient-Tailored Ventilation: A Narrative Review. Tomography 2023; 9:1903-1932. [PMID: 37888742 PMCID: PMC10611090 DOI: 10.3390/tomography9050150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/28/2023] Open
Abstract
Electrical Impedance Tomography (EIT) is a non-invasive bedside imaging technique that provides real-time lung ventilation information on critically ill patients. EIT can potentially become a valuable tool for optimising mechanical ventilation, especially in patients with acute respiratory distress syndrome (ARDS). In addition, EIT has been shown to improve the understanding of ventilation distribution and lung aeration, which can help tailor ventilatory strategies according to patient needs. Evidence from critically ill patients shows that EIT can reduce the duration of mechanical ventilation and prevent lung injury due to overdistension or collapse. EIT can also identify the presence of lung collapse or recruitment during a recruitment manoeuvre, which may guide further therapy. Despite its potential benefits, EIT has not yet been widely used in clinical practice. This may, in part, be due to the challenges associated with its implementation, including the need for specialised equipment and trained personnel and further validation of its usefulness in clinical settings. Nevertheless, ongoing research focuses on improving mechanical ventilation and clinical outcomes in critically ill patients.
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Affiliation(s)
- Serge J. H. Heines
- Department of Intensive Care Medicine, Maastricht University Medical Centre+, 6229 HX Maastricht, The Netherlands; (I.C.C.v.d.H.); (D.C.J.J.B.)
| | - Tobias H. Becher
- Department of Anesthesiology and Intensive Care Medicine, Campus Kiel, University Medical Centre Schleswig-Holstein, 24118 Kiel, Germany;
| | - Iwan C. C. van der Horst
- Department of Intensive Care Medicine, Maastricht University Medical Centre+, 6229 HX Maastricht, The Netherlands; (I.C.C.v.d.H.); (D.C.J.J.B.)
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 HX Maastricht, The Netherlands
| | - Dennis C. J. J. Bergmans
- Department of Intensive Care Medicine, Maastricht University Medical Centre+, 6229 HX Maastricht, The Netherlands; (I.C.C.v.d.H.); (D.C.J.J.B.)
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, 6229 ER Maastricht, The Netherlands
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Ribeiro De Santis Santiago R, Xin Y, Gaulton TG, Alcala G, León Bueno de Camargo ED, Cereda M, Britto Passos Amato M, Berra L. Lung Imaging Acquisition with Electrical Impedance Tomography: Tackling Common Pitfalls. Anesthesiology 2023; 139:329-341. [PMID: 37402247 DOI: 10.1097/aln.0000000000004613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
Electrical impedance tomography is a powerful tool for lung imaging that can be employed at the bedside in multiple clinical scenarios. Diagnosing and preventing interpretation pitfalls will ensure reliable data and allow for appropriate clinical decision-making.
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Affiliation(s)
- Roberta Ribeiro De Santis Santiago
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Yi Xin
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Timothy G Gaulton
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Glasiele Alcala
- Pulmonary Division, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil
| | - Erick Dario León Bueno de Camargo
- Federal University of ABC/Engineering, Modeling and Applied Social Sciences Centre, Biomedical Engineering, São Bernardo do Campo, Brazil
| | - Maurizio Cereda
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Lorenzo Berra
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Slobod D, Damia A, Leali M, Spinelli E, Mauri T. Pathophysiology and Clinical Meaning of Ventilation-Perfusion Mismatch in the Acute Respiratory Distress Syndrome. BIOLOGY 2022; 12:biology12010067. [PMID: 36671759 PMCID: PMC9855693 DOI: 10.3390/biology12010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023]
Abstract
Acute respiratory distress syndrome (ARDS) remains an important clinical challenge with a mortality rate of 35-45%. It is being increasingly demonstrated that the improvement of outcomes requires a tailored, individualized approach to therapy, guided by a detailed understanding of each patient's pathophysiology. In patients with ARDS, disturbances in the physiological matching of alveolar ventilation (V) and pulmonary perfusion (Q) (V/Q mismatch) are a hallmark derangement. The perfusion of collapsed or consolidated lung units gives rise to intrapulmonary shunting and arterial hypoxemia, whereas the ventilation of non-perfused lung zones increases physiological dead-space, which potentially necessitates increased ventilation to avoid hypercapnia. Beyond its impact on gas exchange, V/Q mismatch is a predictor of adverse outcomes in patients with ARDS; more recently, its role in ventilation-induced lung injury and worsening lung edema has been described. Innovations in bedside imaging technologies such as electrical impedance tomography readily allow clinicians to determine the regional distributions of V and Q, as well as the adequacy of their matching, providing new insights into the phenotyping, prognostication, and clinical management of patients with ARDS. The purpose of this review is to discuss the pathophysiology, identification, consequences, and treatment of V/Q mismatch in the setting of ARDS, employing experimental data from clinical and preclinical studies as support.
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Affiliation(s)
- Douglas Slobod
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Critical Care Medicine, McGill University, Montreal, QC H3A 3R1, Canada
| | - Anna Damia
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Marco Leali
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
- Correspondence:
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Borgmann S, Linz K, Braun C, Dzierzawski P, Spassov S, Wenzel C, Schumann S. Lung area estimation using functional tidal electrical impedance variation images and active contouring. Physiol Meas 2022; 43. [PMID: 35764094 DOI: 10.1088/1361-6579/ac7cc3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/28/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Electrical impedance tomography is a valuable tool for monitoring global and regional lung mechanics. To evaluate the recorded data, an accurate estimate of the lung area is crucial. APPROACH We present two novel methods for estimating the lung area using functional tidal images or active contouring methods. A convolutional neural network was trained to determine, whether or not the heart region was visible within tidal images. In addition, the effects of lung area mirroring were investigated. The performance of the methods and the effects of mirroring were evaluated via a score based on the impedance magnitudes in functional tidal images. MAIN RESULTS Our analyses showed that the method based on functional tidal images provided the best estimate of the lung area. Mirroring of the lung area had an impact on the accuracy of area estimation for both methods. The achieved accuracy of the neural network's classification was 94%. For images without a visible heart area, the subtraction of a heart template proved to be a pragmatic approach with good results. SIGNIFICANCE In summary, we developed a routine for estimation of the lung area combined with estimation of the heart area in electrical impedance tomography images.
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Affiliation(s)
- Silke Borgmann
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Kim Linz
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Christian Braun
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Patryk Dzierzawski
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Sashko Spassov
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Christin Wenzel
- Anesthesiology and Critical Care, University of Freiburg Faculty of Medicine, Hugstetter Straße 55, Freiburg, 79106, GERMANY
| | - Stefan Schumann
- Universitatsklinikum Freiburg, Hugstetter Straße 55, Freiburg, 79106, GERMANY
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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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David M, Raison M, Paul S, Cartiaux O, Detrembleur C, Mahaudens P. Locoregional lung ventilation distribution in girls with adolescent idiopathic scoliosis and healthy adolescents. The immediate effect of Schroth 'derotational breathing' exercise in a controlled-trial. Physiother Theory Pract 2022; 39:938-953. [PMID: 35105251 DOI: 10.1080/09593985.2022.2033896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Scoliosis curves present transverse plane deviations due to vertebral rotation. The Schroth method supports thoracic derotation by training patients to exert "derotational" breathing based on assumed enhanced ventilation in areas called "humps" in scoliosis and a patient's ability to voluntarily direct ventilation in less ventilated areas called "flats." OBJECTIVE To assess the asymmetric ventilation distribution and the ability of patients to direct their ventilation to perform derotational breathing. METHODS Twelve girls with adolescent idiopathic scoliosis and 12 healthy girls performed 3 × 3 min of rest, maximal, and derotational breathing. Electrical impedance tomography was used to record locoregional lung ventilation distribution (LLVD) within 4 thoracic regions of interest: anterior right (ROI 1), anterior left (ROI 2), posterior right (ROI 3), and posterior left (ROI 4) quadrants. Humps and flats were the sums of ROI '2 + 3' and ROI '1 + 4,' respectively. RESULTS Overall, no difference in LLVD was observed in the flats and humps between groups. At rest, the LLVD in the humps was more elevated than that in the flats (51.5 ± 8.1% versus 43.6 ± 7.9%; p = .021) when considering both groups. Maximal and derotational breathing led to a more homogeneous LLVD between the humps and flats. CONCLUSION The postulated derotational breathing effect was not confirmed.
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Affiliation(s)
- Mercedes David
- Secteur des Sciences de la Santé, Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium.,Department of Mechanical Engineering, École Polytechnique de Montréal, Montréal, Canada
| | - Maxime Raison
- Department of Mechanical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Department of Rehabilitation, Centre de Readaptation Marie-Enfant du CHU Ste-Justine, Montréal, Canada
| | - Stéphanie Paul
- Secteur des Sciences de la Santé, Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium.,Service d'Orthopédie et de Traumatologie de l'Appareil Locomoteur, Cliniques Universitaires Saint-Luc, Brussels, Belgium.,Service de Médecine Physique et Réadaptation, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Olivier Cartiaux
- Secteur des Sciences de la Santé, Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium
| | - Christine Detrembleur
- Secteur des Sciences de la Santé, Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Mahaudens
- Secteur des Sciences de la Santé, Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium.,Service d'Orthopédie et de Traumatologie de l'Appareil Locomoteur, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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11
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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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12
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The DELUX study: development of lung volumes during extubation of preterm infants. Pediatr Res 2022; 92:242-248. [PMID: 34465873 PMCID: PMC8406659 DOI: 10.1038/s41390-021-01699-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/04/2021] [Accepted: 08/04/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To measure changes in end-expiratory lung impedance (EELI) as a marker of functional residual capacity (FRC) during the entire extubation procedure of very preterm infants. METHODS Prospective observational study in preterm infants born at 26-32 weeks gestation being extubated to non-invasive respiratory support. Changes in EELI and cardiorespiratory parameters (heart rate, oxygen saturation) were recorded at pre-specified events during the extubation procedure compared to baseline (before first handling of the infant). RESULTS Overall, 2912 breaths were analysed in 12 infants. There was a global change in EELI during the extubation procedure (p = 0.029). EELI was lowest at the time of extubation [median (IQR) difference to baseline: -0.30 AU/kg (-0.46; -0.14), corresponding to an FRC loss of 10.2 ml/kg (4.8; 15.9), padj = 0.004]. The biggest EELI loss occurred during adhesive tape removal [median change (IQR): -0.18 AU/kg (-0.22; -0.07), padj = 0.004]. EELI changes were highly correlated with changes in the SpO2/FiO2 ratio (r = 0.48, p < 0.001). Forty per cent of FRC was re-recruited at the tenth breath after the initiation of non-invasive ventilation (p < 0.001). CONCLUSIONS The extubation procedure is associated with significant changes in FRC. This study provides novel information for determining the optimal way of extubating a preterm infant. IMPACT This study is the first to examine the development of lung volumes during the entire extubation procedure including the impact of associated events. The extubation procedure significantly affects functional residual capacity with a loss of approximately 10 ml/kg at the time of extubation. Removal of adhesive tape is the major contributing factor to FRC loss during the extubation procedure. Functional residual capacity is regained within the first breaths after initiation of non-invasive ventilation and is further increased after turning the infant into the prone position.
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Widing H, Chiodaroli E, Liggieri F, Mariotti PS, Hallén K, Perchiazzi G. Homogenizing effect of PEEP on tidal volume distribution during neurally adjusted ventilatory assist: study of an animal model of acute respiratory distress syndrome. Respir Res 2022; 23:324. [PMID: 36419132 PMCID: PMC9685871 DOI: 10.1186/s12931-022-02228-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/26/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The physiological response and the potentially beneficial effects of positive end-expiratory pressure (PEEP) for lung protection and optimization of ventilation during spontaneous breathing in patients with acute respiratory distress syndrome (ARDS) are not fully understood. The aim of the study was to compare the effect of different PEEP levels on tidal volume distribution and on the ventilation of dependent lung region during neurally adjusted ventilatory assist (NAVA). METHODS ARDS-like lung injury was induced by using saline lavage in 10 anesthetized and spontaneously breathing farm-bred pigs. The animals were ventilated in NAVA modality and tidal volume distribution as well as dependent lung ventilation were assessed using electric impedance tomography during the application of PEEP levels from 0 to 15 cmH20, in steps of 3 cmH20. Tidal volume distribution and dependent fraction of ventilation were analysed using Wilcoxon signed rank test. Furthermore, airway, esophageal and transpulmonary pressure, as well as airway flow and delivered volume, were continuously measured during the assisted spontaneous breathing. RESULTS Increasing PEEP improved oxygenation and re-distributed tidal volume. Specifically, ventilation distribution changed from a predominant non-dependent to a more even distribution between non-dependent and dependent areas of the lung. Dependent fraction of ventilation reached 47 ± 9% at PEEP 9 cmH20. Further increasing PEEP led to a predominant dependent ventilation. CONCLUSION During assisted spontaneous breathing in this model of induced ARDS, PEEP modifies the distribution of ventilation and can achieve a homogenizing effect on its spatial arrangement. The study indicates that PEEP is an important factor during assisted spontaneous breathing and that EIT can be of valuable interest when titrating PEEP level during spontaneous breathing, by indicating the most homogeneous distribution of gas volumes throughout the PEEP spectrum.
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Affiliation(s)
- Hannes Widing
- grid.8993.b0000 0004 1936 9457Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Akademiska Sjukhuset, Ing 40, 3 Tr, 751 85 Uppsala, Sweden ,grid.1649.a000000009445082XDepartment of Anaesthesiology and Intensive Care Medicine, Region Västra Götaland, Sahlgrenska University Hospital/Östra, Gothenburg, Sweden
| | - Elena Chiodaroli
- grid.8993.b0000 0004 1936 9457Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Akademiska Sjukhuset, Ing 40, 3 Tr, 751 85 Uppsala, Sweden ,grid.415093.a0000 0004 1793 3800Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Via Di Rudinì 8, Milan, Italy
| | - Francesco Liggieri
- grid.8993.b0000 0004 1936 9457Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Akademiska Sjukhuset, Ing 40, 3 Tr, 751 85 Uppsala, Sweden ,Division of Anesthesia and Intensive Care, San Martino Policlinic University Hospital, 16132 Genoa, Italy
| | - Paola Sara Mariotti
- grid.8993.b0000 0004 1936 9457Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Akademiska Sjukhuset, Ing 40, 3 Tr, 751 85 Uppsala, Sweden ,grid.10796.390000000121049995Department of Medical and Surgical Sciences, Anesthesia and Intensive Care Unit, University of Foggia, Foggia, Italy
| | - Katarina Hallén
- grid.1649.a000000009445082XDepartment of Anaesthesiology and Intensive Care Medicine, Region Västra Götaland, Sahlgrenska University Hospital/Östra, Gothenburg, Sweden
| | - Gaetano Perchiazzi
- grid.8993.b0000 0004 1936 9457Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Akademiska Sjukhuset, Ing 40, 3 Tr, 751 85 Uppsala, Sweden ,grid.412354.50000 0001 2351 3333Department of Anesthesia, Operation and Intensive Care, Uppsala University Hospital, Uppsala, Sweden
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Menden T, Alcaín GB, Stevenson AT, Pollock RD, Tank H, Hodkinson P, Jolley C, Smith TG, Leonhardt S, Walter M. Dynamic lung behavior under high G acceleration monitored with electrical impedance tomography. Physiol Meas 2021; 42. [PMID: 34375953 DOI: 10.1088/1361-6579/ac1c63] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/10/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE During launch and atmospheric re-entry in suborbital space flights, astronauts are exposed to high G-acceleration. These acceleration levels influence gas exchange inside the lung and can potentially lead to hypoxaemia. The distribution of air inside the lung can be monitored by Electrical Impedance Tomography (EIT). This imaging technique might reveal how high gravitational forces affect the dynamic behavior of ventilation and impair gas exchange resulting in hypoxaemia. APPROACH We performed a trial in a long-arm centrifuge with ten participants lying supine while being exposed to +2, +4 and +6\,Gx(chest-to-back acceleration) to study the magnitude of accelerations experienced during suborbital spaceflight. MAIN RESULTS First, the tomographic images revealed that the dorsal region of the lung emptied faster than the ventral region. Second, the ventilated area shifted from dorsal to ventral. Consequently, alveolar pressure in the dorsal area reached the pressure of the upper airways before the ventral area emptied completely. Finally, the upper airways collapsed and the end-expiratory volume increased. This resulted in ventral gas trapping with restricted gas exchange. SIGNIFICANCE At +4xchanges in ventilation distribution varied considerably between subjects potentially due to variation in individual physical conditions. However, at +6\,Gxall participants were affected similarly and the influence of high gravitational conditions was pronounced.
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Affiliation(s)
- Tobias Menden
- Chair for Medical Information Technology, RWTH Aachen University, Aachen, Nordrhein-Westfalen, GERMANY
| | - Gema B Alcaín
- Chair for Medical Information Technology, RWTH Aachen University, Aachen, Nordrhein-Westfalen, GERMANY
| | - Alec T Stevenson
- QinetiQ EMEA, Farnborough, Hampshire, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Ross D Pollock
- King's College London Centre of Human and Aerospace Physiological Sciences, London, London, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Henry Tank
- QinetiQ EMEA, Farnborough, Hampshire, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Peter Hodkinson
- King's College London Centre of Human and Aerospace Physiological Sciences, London, London, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Caroline Jolley
- King's College London Centre of Human and Aerospace Physiological Sciences, London, London, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Thomas G Smith
- King's College London Centre of Human and Aerospace Physiological Sciences, London, London, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Steffen Leonhardt
- Chair for Medical Information Technology, RWTH Aachen University, Aachen, Nordrhein-Westfalen, GERMANY
| | - Marian Walter
- Chair for Medical Information Technology, RWTH Aachen University, Aachen, Nordrhein-Westfalen, GERMANY
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Secombe C, Adler A, Hosgood G, Raisis A, Mosing M. Can bronchoconstriction and bronchodilatation in horses be detected using electrical impedance tomography? J Vet Intern Med 2021; 35:2035-2044. [PMID: 33977584 PMCID: PMC8295671 DOI: 10.1111/jvim.16152] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Electrical impedance tomography (EIT) generates images of the lungs based on impedance change and was able to detect changes in airflow after histamine challenge in horses. OBJECTIVES To confirm that EIT can detect histamine-provoked changes in airflow and subsequent drug-induced bronchodilatation. Novel EIT flow variables were developed and examined for changes in airflow. METHODS Bronchoconstriction was induced using stepwise histamine bronchoprovocation in 17 healthy sedated horses. The EIT variables were recorded at baseline, after saline nebulization (control), at the histamine concentration causing bronchoconstriction (Cmax ) and 2 and 10 minutes after albuterol (salbutamol) administration. Peak global inspiratory (PIFEIT ) and peak expiratory EIT (PEFEIT ) flow, slope of the global expiratory flow-volume curve (FVslope ), steepest FVslope over all pixels in the lung field, total impedance change (surrogate for tidal volume; VTEIT ) and intercept on the expiratory FV curve normalized to VTEIT (FVintercept /VTEIT ) were indexed to baseline and analyzed for a difference from the control, at Cmax , 2 and 10 minutes after albuterol. Multiple linear regression explored the explanation of the variance of Δflow, a validated variable to evaluate bronchoconstriction using all EIT variables. RESULTS At Cmax , PIFEIT , PEFEIT , and FVslope significantly increased whereas FVintercept /VT decreased. All variables returned to baseline 10 minutes after albuterol. The VTEIT did not change. Multivariable investigation suggested 51% of Δflow variance was explained by a combination of PIFEIT and PEFEIT . CONCLUSIONS AND CLINICAL IMPORTANCE Changes in airflow during histamine challenge and subsequent albuterol administration could be detected by various EIT flow volume variables.
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Affiliation(s)
- Cristy Secombe
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Andy Adler
- Systems and Computer Engineering, Carleton UniversityOttawaCanada
| | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Anthea Raisis
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Martina Mosing
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
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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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Abstract
PURPOSE OF REVIEW Among noninvasive lung imaging techniques that can be employed at the bedside electrical impedance tomography (EIT) and lung ultrasound (LUS) can provide dynamic, repeatable data on the distribution regional lung ventilation and response to therapeutic manoeuvres.In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT and Point of Care Ultrasound (PoCUS, mainly but not limited to LUS) in the management of mechanically ventilated patients. RECENT FINDINGS The use of EIT in clinical practice is supported by several studies demonstrating good correlation between impedance tomography data and other validated methods of assessing lung aeration during mechanical ventilation. Similarly, LUS also correlates with chest computed tomography in assessing lung aeration, its changes and several pathological conditions, with superiority over other techniques. Other PoCUS applications have shown to effectively complement the LUS ultrasound assessment of the mechanically ventilated patient. SUMMARY Bedside techniques - such as EIT and PoCUS - are becoming standards of the care for mechanically ventilated patients to monitor the changes in lung aeration, ventilation and perfusion in response to treatment and to assess weaning from mechanical ventilation.
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18
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Cornejo R, Iturrieta P, Olegário TMM, Kajiyama C, Arellano D, Guiñez D, Cerda MA, Brito R, Gajardo AIJ, Lazo M, López L, Morais CCA, González S, Zavala M, Rojas V, Medel JN, Hurtado DE, Bruhn A, Ramos C, Estuardo N. Estimation of changes in cyclic lung strain by electrical impedance tomography: Proof-of-concept study. Acta Anaesthesiol Scand 2021; 65:228-235. [PMID: 33037607 DOI: 10.1111/aas.13723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 09/15/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023]
Abstract
RATIONALE Cyclic strain may be a determinant of ventilator-induced lung injury. The standard for strain assessment is the computed tomography (CT), which does not allow continuous monitoring and exposes to radiation. Electrical impedance tomography (EIT) is able to monitor changes in regional lung ventilation. In addition, there is a correlation between mechanical deformation of materials and detectable changes in its electrical impedance, making EIT a potential surrogate for cyclic lung strain measured by CT (StrainCT ). OBJECTIVES To compare the global StrainCT with the change in electrical impedance (ΔZ). METHODS Acute respiratory distress syndrome patients under mechanical ventilation (VT 6 mL/kg ideal body weight with positive end-expiratory pressure 5 [PEEP 5] and best PEEP according to EIT) underwent whole-lung CT at end-inspiration and end-expiration. Biomechanical analysis was used to construct 3D maps and determine StrainCT at different levels of PEEP. CT and EIT acquisitions were performed simultaneously. Multilevel analysis was employed to determine the causal association between StrainCT and ΔZ. Linear regression models were used to predict the change in lung StrainCT between different PEEP levels based on the change in ΔZ. MAIN RESULTS StrainCT was positively and independently associated with ΔZ at global level (P < .01). Furthermore, the change in StrainCT (between PEEP 5 and Best PEEP) was accurately predicted by the change in ΔZ (R2 0.855, P < .001 at global level) with a high agreement between predicted and measured StrainCT . CONCLUSIONS The change in electrical impedance may provide a noninvasive assessment of global cyclic strain, without radiation at bedside.
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Affiliation(s)
- Rodrigo Cornejo
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
- Center of Acute Respiratory Critical Illness (ARCI) Santiago Chile
| | - Pablo Iturrieta
- Department of Structural and Geotechnical Engineering School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
| | | | | | - Daniel Arellano
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
- Departamento de kinesiología Facultad de Medicina Universidad de Chile Santiago Chile
| | - Dannette Guiñez
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - María A. Cerda
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Roberto Brito
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Abraham I. J. Gajardo
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Marioli Lazo
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Lorena López
- Departamento de Radiología Hospital Clínico Universidad de Chile Santiago Chile
| | - Caio C. A. Morais
- Divisao de Pneumologia Faculdade de Medicina Instituto do Coracao Hospital das Clinicas HCFMUSP Universidade de Sao Paulo Sao Paulo Brazil
| | - Sedric González
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Miguel Zavala
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Verónica Rojas
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Juan N. Medel
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
| | - Daniel E. Hurtado
- Department of Structural and Geotechnical Engineering School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
- Institute for Biological and Medical Engineering School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
| | - Alejandro Bruhn
- Center of Acute Respiratory Critical Illness (ARCI) Santiago Chile
- Departamento de Medicina Intensiva Facultad de Medicina Pontificia Universidad Católica de Chile Santiago Chile
| | - Cristobal Ramos
- Departamento de Radiología Hospital Clínico Universidad de Chile Santiago Chile
| | - Nivia Estuardo
- Unidad de Pacientes Críticos Departamento de Medicina Hospital Clínico Universidad de Chile Santiago Chile
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Hahn G, Niewenhuys J, Just A, Tonetti T, Behnemann T, Rapetti F, Collino F, Vasques F, Maiolo G, Romitti F, Gattinoni L, Quintel M, Moerer O. Monitoring lung impedance changes during long-term ventilator-induced lung injury ventilation using electrical impedance tomography. Physiol Meas 2020; 41:095011. [PMID: 33035199 DOI: 10.1088/1361-6579/abb1fb] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The target of this methodological evaluation was the feasibility of long-term monitoring of changes in lung conditions by time-difference electrical impedance tomography (tdEIT). In contrast to ventilation monitoring by tdEIT, the monitoring of end-expiratory (EELIC) or end-inspiratory (EILIC) lung impedance change always requires a reference measurement. APPROACH To determine the stability of the used Pulmovista 500® EIT system, as a prerequisite it was initially secured on a resistive phantom for 50 h. By comparing the slopes of EELIC for the whole lung area up to 48 h from 36 pigs ventilated at six positive end-expiratory pressure (PEEP) levels from 0 to 18 cmH2O we found a good agreement (range of r 2 = 0.93-1.0) between absolute EIT (aEIT) and tdEIT values. This justified the usage of tdEIT with its superior local resolution compared to aEIT for long-term determination of EELIC. MAIN RESULTS The EELIC was between -0.07 Ωm day-1 at PEEP 4 and -1.04 Ωm day-1 at PEEP 18 cmH2O. The complex local time pattern for EELIC was roughly quantified by the new parameter, centre of end-expiratory change (CoEEC), in equivalence to the established centre of ventilation (CoV). The ventrally located mean of the CoV was fairly constant in the range of 42%-46% of thorax diameter; however, on the contrary, the CoEEC shifted from about 40% to about 75% in the dorsal direction for PEEP levels of 14 and 18 cmH2O. SIGNIFICANCE The observed shifts started earlier for higher PEEP levels. Changes of EELI could be precisely monitored over a period of 48 h by tdEIT on pigs.
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Affiliation(s)
- G Hahn
- Department of Anaesthesiology, University Medical Center Göttingen (UMG), Robert-Koch-Str. 40, D-37075, Göttingen, Germany
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Sophocleous L, Waldmann AD, Becher T, Kallio M, Rahtu M, Miedema M, Papadouri T, Karaoli C, Tingay DG, Van Kaam AH, Yerworth R, Bayford R, Frerichs I. Effect of sternal electrode gap and belt rotation on the robustness of pulmonary electrical impedance tomography parameters. Physiol Meas 2020; 41:035003. [DOI: 10.1088/1361-6579/ab7b42] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Braun F, Proença M, Wendler A, Solà J, Lemay M, Thiran JP, Weiler N, Frerichs I, Becher T. Noninvasive measurement of stroke volume changes in critically ill patients by means of electrical impedance tomography. J Clin Monit Comput 2019; 34:903-911. [PMID: 31624996 DOI: 10.1007/s10877-019-00402-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/10/2019] [Indexed: 10/25/2022]
Abstract
Previous animal experiments have suggested that electrical impedance tomography (EIT) has the ability to noninvasively track changes in cardiac stroke volume (SV). The present study intended to reproduce these findings in patients during a fluid challenge. In a prospective observational study including critically ill patients on mechanical ventilation, SV was estimated via ECG-gated EIT before and after a fluid challenge and compared to transpulmonary thermodilution reference measurements. Relative changes in EIT-derived cardiosynchronous impedance changes in the heart ([Formula: see text]) and lung region ([Formula: see text]) were compared to changes in reference SV by assessing the concordance rate (CR) and Pearson's correlation coefficient (R). We compared 39 measurements of 20 patients. [Formula: see text] did not show to be a reliable estimate for tracking changes of SV (CR = 52.6% and R = 0.13 with P = 0.44). In contrast, [Formula: see text] showed an acceptable trending performance (CR = 94.4% and R = 0.72 with P < 0.0001). Our results indicate that ECG-gated EIT measurements of [Formula: see text] are able to noninvasively monitor changes in SV during a fluid challenge in critically ill patients. However, this was not possible using [Formula: see text]. The present approach is limited by the influences induced by ventilation, posture or changes in electrode-skin contact and requires further validation.
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Affiliation(s)
- Fabian Braun
- Centre Suisse d'Electronique et de Microtechnique (CSEM SA), Rue Jaquet-Droz 1, 2002, Neuchâtel, Switzerland. .,Signal Processing Laboratory LTS5, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland.
| | - Martin Proença
- Centre Suisse d'Electronique et de Microtechnique (CSEM SA), Rue Jaquet-Droz 1, 2002, Neuchâtel, Switzerland.,Signal Processing Laboratory LTS5, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Anna Wendler
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Josep Solà
- Centre Suisse d'Electronique et de Microtechnique (CSEM SA), Rue Jaquet-Droz 1, 2002, Neuchâtel, Switzerland
| | - Mathieu Lemay
- Centre Suisse d'Electronique et de Microtechnique (CSEM SA), Rue Jaquet-Droz 1, 2002, Neuchâtel, Switzerland
| | - Jean-Phillipe Thiran
- Signal Processing Laboratory LTS5, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland.,Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Norbert Weiler
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Tobias Becher
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
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Vasques F, Sanderson B, Barrett NA, Camporota L. Monitoring of regional lung ventilation using electrical impedance tomography. Minerva Anestesiol 2019; 85:1231-1241. [PMID: 30945516 DOI: 10.23736/s0375-9393.19.13477-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Among recent lung imaging techniques and devices, electrical impedance tomography (EIT) can provide dynamic information on the distribution regional lung ventilation. EIT images possess a high temporal and functional resolution allowing the visualization of dynamic physiological and pathological changes on a breath-by-breath basis. EIT detects changes in electric impedance (i.e., changes in gas/fluid ratio) and describes them in real time, both visually through images and waveforms, and numerically, allowing the clinician to monitor disease evolution and response to treatment. The use of EIT in clinical practice is supported by several studies demonstrating a good correlation between impedance tomography data and other validated methods of measuring lung volume. In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT in the management of mechanically ventilated patients.
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Affiliation(s)
- Francesco Vasques
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, King's Health Partners, London, UK.,Division of Centre of Human Applied Physiological Sciences, King's College London, London, UK
| | - Barnaby Sanderson
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, King's Health Partners, London, UK.,Division of Centre of Human Applied Physiological Sciences, King's College London, London, UK
| | - Nicholas A Barrett
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, King's Health Partners, London, UK.,Division of Centre of Human Applied Physiological Sciences, King's College London, London, UK
| | - Luigi Camporota
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, King's Health Partners, London, UK - .,Division of Centre of Human Applied Physiological Sciences, King's College London, London, UK
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Zhang C, Dai M, Liu W, Bai X, Wu J, Xu C, Xia J, Fu F, Shi X, Dong X, Jin F, You F. Global and regional degree of obstruction determined by electrical impedance tomography in patients with obstructive ventilatory defect. PLoS One 2018; 13:e0209473. [PMID: 30571739 PMCID: PMC6301672 DOI: 10.1371/journal.pone.0209473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 12/06/2018] [Indexed: 11/19/2022] Open
Abstract
Background Electrical impedance tomography is a continuous imaging method capable of measuring lung volume changes. The purpose of this study was to examine whether EIT was capable of evaluating the degree of obstructive ventilatory defect (OVD) on the global and regional level. Methods 41 healthy subjects with no lung diseases and 67 subjects suffering from obstructive lung diseases were examined using EIT and spirometry during forced vital capacity (FVC) maneuver. The subjects were divided into control group (n = 41), early airway obstruction group (n = 26), mild group (n = 17), moderate group (n = 16) and severe group (n = 8) according to the degree of obstruction. Forced expiratory volume in 1 second (FEV1) and FEV1/FVC were determined by EIT. The mode index (MI) was proposed to evaluate the degree of global and regional obstruction; the effectiveness of MI was validated by evaluating posture related change of lung emptying capacity in sitting and supine postures; the degree of regional obstruction was determined according to the cut-off values of MI obtained from receiver operating characteristic (ROC) analysis; regional obstruction was located in the four-quadrant region of interest (ROI) and the contour-map ROI with contour lines at the cut-off values of MI. Results Significant differences were found between different groups (P<0.05) and the global MI was 0.93±0.03, 0.86±0.05, 0.81±0.09, 0.73±0.09 and 0.60±0.11 (mean ±SD), respectively. The cut-off MI value was 0.90, 0.83, 0.77, and 0.65, respectively. Conclusion The results indicated the potential of EIT to evaluate the degree of obstruction in patients with obstructive ventilatory defect on the global and regional level.
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Affiliation(s)
- Chao Zhang
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China.,Medical Engineering Section, General Hospital of Shenyang Military Region, Shenyang, Liaoning, China
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Wei Liu
- Department of respiratory medicine, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiaohui Bai
- The Fifth People's Hospital of Baoji City, Baoji, Shaanxi, China
| | - Jiaming Wu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Medical Technology, Bethune Military Medical NCO Academy of PLA, Shijiazhuang, Hebei, China
| | - Canhua Xu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Junying Xia
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xuetao Shi
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiuzhen Dong
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Faguang Jin
- Department of respiratory medicine, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Fusheng You
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, Shaanxi, China
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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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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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26
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Schullcke B, Gong B, Krueger-Ziolek S, Tawhai M, Adler A, Mueller-Lisse U, Moeller K. Lobe based image reconstruction in Electrical Impedance Tomography. Med Phys 2017; 44:426-436. [PMID: 28121374 DOI: 10.1002/mp.12038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/22/2016] [Accepted: 11/25/2016] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Electrical Impedance Tomography (EIT) is an imaging modality used to generate two-dimensional cross-sectional images representing impedance change in the thorax. The impedance of lung tissue changes with change in air content of the lungs; hence, EIT can be used to examine regional lung ventilation in patients with abnormal lungs. In lung EIT, electrodes are attached around the circumference of the thorax to inject small alternating currents and measure resulting voltages. In contrast to X-ray computed tomography (CT), EIT images do not depict a thorax slice of well defined thickness, but instead visualize a lens-shaped region around the electrode plane, which results from diffuse current propagation in the thorax. Usually, this is considered a drawback, since image interpretation is impeded if 'off-plane' conductivity changes are projected onto the reconstructed two-dimensional image. In this paper we describe an approach that takes advantage of current propagation below and above the electrode plane. The approach enables estimation of the individual conductivity change in each lung lobe from boundary voltage measurements. This could be used to monitor disease progression in patients with obstructive lung diseases, such as chronic obstructive pulmonary disease (COPD) or cystic fibrosis (CF) and to obtain a more comprehensive insight into the pathophysiology of the lung. METHODS Electrode voltages resulting from different conductivities in each lung lobe were simulated utilizing a realistic 3D finite element model (FEM) of the human thorax and the lungs. Overall 200 different patterns of conductivity change were simulated. A 'lobe reconstruction' algorithm was developed, applying patient-specific anatomical information in the reconstruction process. A standard EIT image reconstruction algorithm and the proposed 'lobe reconstruction' algorithm were used to estimate conductivity change in the lobes. The agreement between simulated and reconstructed conductivity change in particular lobes were compared using Bland-Altman plots, correlation plots and linear regression. To test the applicability of the approach in a realistic scenario, EIT measurements of a patient suffering from cystic fibrosis (CF) were carried out. RESULTS Conductivity changes in each lobe generate specific patterns of voltage change. These can be used to estimate the conductivity change in lobes from measured boundary voltage. The correlation coefficient between simulated and reconstructed conductivity change in particular lobes is r > 0.89 for all lobes. Unknown position of the electrode plane leads to over- or underestimation of reconstructed conductivity change. Slight mismatches (± 5% of the forward model height) between the actual position of the electrode plane and the position used in the reconstruction model lead to regression coefficients of 0.7 to 1.3 between simulated and reconstructed conductivity change in the lobes. CONCLUSION The presented approach enhances common reconstruction methods by providing information about anatomically assignable units and thus facilitates image interpretation, since impedance change and thus ventilation of each lobe is directly determined in the reconstructions.
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Affiliation(s)
- Benjamin Schullcke
- Institute of Technical Medicine, Furtwangen University, 78045, VS-Schwenningen, Germany.,Department of Radiology, University of Munich, 80336, Munich, Germany
| | - Bo Gong
- Institute of Technical Medicine, Furtwangen University, 78045, VS-Schwenningen, Germany.,Department of Radiology, University of Munich, 80336, Munich, Germany
| | - Sabine Krueger-Ziolek
- Institute of Technical Medicine, Furtwangen University, 78045, VS-Schwenningen, Germany.,Department of Radiology, University of Munich, 80336, Munich, Germany
| | - Merryn Tawhai
- Auckland Bioengineering Institute, University of Auckland, Auckland, 1010, New Zealand
| | - Andy Adler
- Systems and Computer Engineering, Carlton University, Ottawa, ON, K1S 5B6, Canada
| | | | - Knut Moeller
- Institute of Technical Medicine, Furtwangen University, 78045, VS-Schwenningen, Germany
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27
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Wilsterman MEF, de Jager P, Blokpoel R, Frerichs I, Dijkstra SK, Albers MJIJ, Burgerhof JGM, Markhorst DG, Kneyber MCJ. Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure. Ann Intensive Care 2016; 6:103. [PMID: 27783382 PMCID: PMC5081313 DOI: 10.1186/s13613-016-0206-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 10/17/2016] [Indexed: 01/10/2023] Open
Abstract
Background Neuromuscular blockade (NMB) has been shown to improve outcome in acute respiratory distress syndrome (ARDS) in adults, challenging maintaining spontaneous breathing when there is severe lung injury. We tested in a prospective physiological study the hypothesis that continuous administration of NMB agents in mechanically ventilated children with severe acute hypoxemic respiratory failure (AHRF) improves the oxygenation index without a redistribution of tidal volume VT toward non-dependent lung zones. Methods Oxygenation index, PaO2/FiO2 ratio, lung mechanics (plateau pressure, mean airway pressure, respiratory system compliance and resistance), hemodynamics (heart rate, central venous and arterial blood pressures), oxygenation [oxygenation index (OI), PaO2/FiO2 and SpO2/FiO2], ventilation (physiological dead space-to-VT ratio) and electrical impedance tomography measured changes in end-expiratory lung volume (EELV), and VT distribution was measured before and 15 min after the start of continuous infusion of rocuronium 1 mg/kg. Patients were ventilated in a time-cycled, pressure-limited mode with pre-set VT. All ventilator settings were not changed during the study. Results Twenty-two patients were studied (N = 18 met the criteria for pediatric ARDS). Median age (25–75 interquartile range) was 15 (7.8–77.5) weeks. Pulmonary pathology was present in 77.3%. The median lung injury score was 9 (8–10). The overall median CoV and regional lung filling characteristics were not affected by NMB, indicating no ventilation shift toward the non-dependent lung zones. Regional analysis showed a homogeneous time course of lung inflation during inspiration, indicating no tendency to atelectasis after the introduction of NMB. NMB decreased the mean airway pressure (p = 0.039) and OI (p = 0.039) in all patients. There were no significant changes in lung mechanics, hemodynamics and EELV. Subgroup analysis showed that OI decreased (p = 0.01) and PaO2/FiO2 increased (p = 0.02) in patients with moderate or severe PARDS. Conclusions NMB resulted in an improved oxygenation index in pediatric patients with AHRF. Distribution of VT and regional lung filling characteristics were not affected.
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Affiliation(s)
- Marlon E F Wilsterman
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.,Department of Paediatrics, Nij Smellinghe Hospital, Drachten, The Netherlands
| | - Pauline de Jager
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Robert Blokpoel
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Inez Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Sandra K Dijkstra
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Marcel J I J Albers
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Johannes G M Burgerhof
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dick G Markhorst
- Division of Paediatric Intensive Care, Department of Paediatrics, VU University Medical Center, Amsterdam, The Netherlands
| | - Martin C J Kneyber
- Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. .,Critical Care, Anaesthesia, Peri-operative Medicine and Emergency Medicine (CAPE), University of Groningen, Groningen, The Netherlands.
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28
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Frerichs I, Amato MBP, van Kaam AH, Tingay DG, Zhao Z, Grychtol B, Bodenstein M, Gagnon H, Böhm SH, Teschner E, Stenqvist O, Mauri T, Torsani V, Camporota L, Schibler A, Wolf GK, Gommers D, Leonhardt S, Adler A. Chest electrical impedance tomography examination, data analysis, terminology, clinical use and recommendations: consensus statement of the TRanslational EIT developmeNt stuDy group. Thorax 2016; 72:83-93. [PMID: 27596161 PMCID: PMC5329047 DOI: 10.1136/thoraxjnl-2016-208357] [Citation(s) in RCA: 474] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/12/2016] [Accepted: 07/16/2016] [Indexed: 11/04/2022]
Abstract
Electrical impedance tomography (EIT) has undergone 30 years of development. Functional chest examinations with this technology are considered clinically relevant, especially for monitoring regional lung ventilation in mechanically ventilated patients and for regional pulmonary function testing in patients with chronic lung diseases. As EIT becomes an established medical technology, it requires consensus examination, nomenclature, data analysis and interpretation schemes. Such consensus is needed to compare, understand and reproduce study findings from and among different research groups, to enable large clinical trials and, ultimately, routine clinical use. Recommendations of how EIT findings can be applied to generate diagnoses and impact clinical decision-making and therapy planning are required. This consensus paper was prepared by an international working group, collaborating on the clinical promotion of EIT called TRanslational EIT developmeNt stuDy group. It addresses the stated needs by providing (1) a new classification of core processes involved in chest EIT examinations and data analysis, (2) focus on clinical applications with structured reviews and outlooks (separately for adult and neonatal/paediatric patients), (3) a structured framework to categorise and understand the relationships among analysis approaches and their clinical roles, (4) consensus, unified terminology with clinical user-friendly definitions and explanations, (5) a review of all major work in thoracic EIT and (6) recommendations for future development (193 pages of online supplements systematically linked with the chief sections of the main document). We expect this information to be useful for clinicians and researchers working with EIT, as well as for industry producers of this technology.
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Affiliation(s)
- Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Marcelo B P Amato
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology PAMB, Mannheim, Germany
| | - Marc Bodenstein
- Department of Anesthesiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Hervé Gagnon
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | | | | | - Ola Stenqvist
- Department of Anesthesiology and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Vinicius Torsani
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Luigi Camporota
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Andreas Schibler
- Paediatric Critical Care Research Group, Mater Research University of Queensland, South Brisbane, Australia
| | - Gerhard K Wolf
- Children's Hospital Traunstein, Ludwig Maximilian's University, Munich, Germany
| | - Diederik Gommers
- Department of Adult Intensive Care, Erasmus MC, Rotterdam, The Netherlands
| | - Steffen Leonhardt
- Philips Chair for Medical Information Technology, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
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Krueger-Ziolek S, Schullcke B, Zhao Z, Gong B, Naehrig S, Müller-Lisse U, Moeller K. Multi-layer ventilation inhomogeneity in cystic fibrosis. Respir Physiol Neurobiol 2016; 233:25-32. [PMID: 27476932 DOI: 10.1016/j.resp.2016.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022]
Abstract
Differences in regional lung function between the 3rd and 5th intercostal space (ICS) were explored in 10 cystic fibrosis (CF) patients and compared to 10 lung-healthy controls by electrical impedance tomography (EIT). Regional ratios of impedance changes corresponding to the maximal volume of air exhaled within the first second of a forced expiration (ΔIFEV1) and the forced vital capacity (ΔIFVC) were determined. Regional airway obstruction and ventilation inhomogeneity were assessed by the frequency distribution of these ratios (ΔIFEV1/ΔIFVC) and an inhomogeneity index (GITI). The mean of the frequency distribution of ΔIFEV1/ΔIFVC and the GITI in both thorax planes were significantly different between CF patients and controls (p<0.001). CF patients exhibited a significantly lower mean of ΔIFEV1/ΔIFVC frequency distribution (p<0.05) and a significantly higher degree of ventilation inhomogeneity (p<0.01) in the 3rd ICS compared to the 5th ICS. Results indicated that EIT measurements at more cranial thorax planes may benefit the early diagnosis in CF.
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Affiliation(s)
- Sabine Krueger-Ziolek
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1).
| | - Benjamin Schullcke
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany
| | - Bo Gong
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany; Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Susanne Naehrig
- Medizinische Klinik V (Pneumology), LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Ullrich Müller-Lisse
- Department of Radiology, LMU University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany(1)
| | - Knut Moeller
- Institute of Technical Medicine, Furtwangen University, Jakob-Kienzle-Straße 17, 78054 Villingen-Schwenningen, Germany
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30
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Lehmann S, Leonhardt S, Ngo C, Bergmann L, Schrading S, Heimann K, Wagner N, Tenbrock K. Electrical impedance tomography as possible guidance for individual positioning of patients with multiple lung injury. CLINICAL RESPIRATORY JOURNAL 2016; 12:68-75. [PMID: 27058971 DOI: 10.1111/crj.12481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 03/08/2016] [Accepted: 03/31/2016] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Electrical Impedance Tomography (EIT) is a tomographic, radiation-free technique based on the injection of a harmless alternating current. OBJECTIVE As electrical impedance strictly correlates with the variation of air content, EIT delivers highly dynamic information about global and regional ventilation. We want to demonstrate the potential of EIT individualizing ventilation by positioning. METHODS Gravity-dependent EIT findings were analyzed retrospectively in a critically ill mechanically ventilated pediatric patient with cystic fibrosis and coincident lung diseases. To further evaluate gravity-dependent changes in ventilation, six adult healthy and spontaneously breathing volunteers were investigated during simultaneous detection of EIT, breathing patterns, tidal volume (VT) and breathing frequency (BF). RESULTS EIT findings in healthy lungs in five positions showed gravity-dependent effects of ventilation with overall ventilation of predominantly the right lung (except during left-side positioning) and with the ventral lung in supine, prone and upright position. These EIT-derived observations are in line with pathophysiological mechanisms and earlier EIT studies. Unexpectedly, the patient with cystic fibrosis and lobectomy of the right upper and middle lobe one year earlier, showed improvement of global and regional ventilation in the right position despite reduced lung volume and overinflation of this side. This resulted in individualized positioning and improvement of ventilation. CONCLUSIONS Although therapeutic recommendations are available for gravitational influences of lung ventilation, they can be contradictory depending on the underlying lung disease. EIT has the potential to guide therapists in the positioning of patients according to their individual condition and disease, especially in case of multiple lung injury.
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Affiliation(s)
- Sylvia Lehmann
- Department of Pediatrics, Division Pediatric Pulmonology, University Hospital RWTH Aachen, 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
| | - Simone Schrading
- Department of Radiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Konrad Heimann
- Department of Pediatrics, Division of Neonatology, University Hospital RWTH Aachen, Aachen, Germany
| | - Norbert Wagner
- Department of Pediatrics, Division Pediatric Pulmonology, University Hospital RWTH Aachen, Aachen, Germany
| | - Klaus Tenbrock
- Department of Pediatrics, Division Pediatric Pulmonology, University Hospital RWTH Aachen, Aachen, Germany
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van der Burg PS, de Jongh FH, Miedema M, Frerichs I, van Kaam AH. The effect of prolonged lateral positioning during routine care on regional lung volume changes in preterm infants. Pediatr Pulmonol 2016; 51:280-5. [PMID: 26291607 DOI: 10.1002/ppul.23254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 06/04/2015] [Accepted: 07/03/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION During routine nursing care, preterm infants are often placed in lateral position for several hours, but the effect of this procedure on regional lung volume and ventilation is unknown. In our study we examined this effect during 3 hrs of lateral positioning in stable preterm infants. METHODS Preterm infants on non-invasive respiratory support were eligible for the study. Infants were placed in supine position and subsequently transferred to right or left lateral position, according to their individual routine nursing schedule. Changes in end-expiratory lung volume (EELV), tidal volume (VT ) and ventilation distribution were recorded using electrical impedance tomography (EIT), starting 10 min before and up to 180 min after the positional change. Additionally, oxygen requirement, transcutaneous oxygen saturation and respiratory rate were recorded. RESULTS 15 infants were included (GA 28.9 ± 2.0 wk, BW 1167 ± 290 g). EELV increased significantly after changing to lateral position, stabilizing at a median value of 40.8 (IQR 29.0-99.3) AU/kg at 30 min. This increase could almost be exclusively attributed to the non-dependent lung regions. Tidal volume, oxygenation, and respiratory rate remained stable. Changing to the right, but not the left, lateral position resulted in a rapid but transient shift in ventilation to the dependent lung regions. After 180 min there were no differences in ventilation distribution between lateral and supine positioning. CONCLUSION This study shows that lateral position up to 3 hours, as part of normal nursing care of preterm infants, has no adverse effects on lung volumes and its regional distribution.
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Affiliation(s)
- Pauline S van der Burg
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Frans H de Jongh
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Martijn Miedema
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Inez Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Germany
| | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
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Krueger-Ziolek S, Schullcke B, Kretschmer J, Müller-Lisse U, Möller K, Zhao Z. Positioning of electrode plane systematically influences EIT imaging. Physiol Meas 2015; 36:1109-18. [DOI: 10.1088/0967-3334/36/6/1109] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hsu CF, Cheng JS, Lin WC, Ko YF, Cheng KS, Lin SH, Chen CW. Electrical impedance tomography monitoring in acute respiratory distress syndrome patients with mechanical ventilation during prolonged positive end-expiratory pressure adjustments. J Formos Med Assoc 2015; 115:195-202. [PMID: 25843526 DOI: 10.1016/j.jfma.2015.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/23/2015] [Accepted: 03/02/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND/PURPOSE The time required to reach oxygenation equilibrium after positive end-expiratory pressure (PEEP) adjustments in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) is unclear. We used electrical impedance tomography to elucidate gas distribution and factors related to oxygenation status following PEEP in patients with ARDS. METHODS Nineteen mechanically ventilated ARDS patients were placed on baseline PEEP (PEEPB) for 1 hour, PEEPB - 4 cmH2O PEEP (PEEPL) for 30 minutes, and PEEPB + 4 cmH2O PEEP (PEEPH) for 1 hour. Tidal volume and respiratory rate were similar. Impedance changes, respiratory parameters, and arterial blood gases were measured at baseline, 5 minutes, and 30 minutes after PEEPL, and 5 minutes, 15 minutes, 30 minutes, and 1 hour after PEEPH. RESULTS PaO2/fraction of inspired oxygen (P/F ratio) decreased quickly from PEEPB to PEEPL, and stabilized 5 minutes after PEEPL. However the P/F ratio progressively increased from PEEPL to PEEPH, and a significantly higher P/F ratio and end-expiratory lung impedance were found at 60 minutes compared to 5 minutes after PEEPH. The end-expiratory lung impedance level significantly correlated with P/F ratio (p < 0.001). With increasing PEEP, dorsal ventilation significantly increased; however, regional ventilation did not change over time with PEEP level. CONCLUSION Late improvements in oxygenation following PEEP escalation are probably due to slow recruitment in ventilated ARDS patients. Electrical impedance tomography may be an appropriate tool to assess recruitment and oxygenation status in patients with changes in PEEP.
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Affiliation(s)
- Chia-Fu Hsu
- Medical Intensive Care Unit, Department of Internal Medicine, National Cheng Kung University Affiliated Hospital, Tainan, Taiwan
| | - Jen-Suo Cheng
- Medical Intensive Care Unit, Department of Internal Medicine, National Cheng Kung University Affiliated Hospital, Tainan, Taiwan
| | - Wei-Chi Lin
- Medical Intensive Care Unit, Department of Internal Medicine, National Cheng Kung University Affiliated Hospital, Tainan, Taiwan
| | - Yen-Fen Ko
- Bioengineering Institute, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kuo-Sheng Cheng
- Bioengineering Institute, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Sheng-Hsiang Lin
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chang-Wen Chen
- Medical Intensive Care Unit, Department of Internal Medicine, National Cheng Kung University Affiliated Hospital, Tainan, Taiwan; Medical Device Innovation Center, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
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REINIUS H, BORGES JB, FREDÉN F, JIDEUS L, CAMARGO EDLB, AMATO MBP, HEDENSTIERNA G, LARSSON A, LENNMYR F. Real-time ventilation and perfusion distributions by electrical impedance tomography during one-lung ventilation with capnothorax. Acta Anaesthesiol Scand 2015; 59:354-68. [PMID: 25556329 DOI: 10.1111/aas.12455] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/17/2014] [Indexed: 01/18/2023]
Abstract
BACKGROUND Carbon dioxide insufflation into the pleural cavity, capnothorax, with one-lung ventilation (OLV) may entail respiratory and hemodynamic impairments. We investigated the online physiological effects of OLV/capnothorax by electrical impedance tomography (EIT) in a porcine model mimicking the clinical setting. METHODS Five anesthetized, muscle-relaxed piglets were subjected to first right and then left capnothorax with an intra-pleural pressure of 19 cm H2 O. The contra-lateral lung was mechanically ventilated with a double-lumen tube at positive end-expiratory pressure 5 and subsequently 10 cm H2 O. Regional lung perfusion and ventilation were assessed by EIT. Hemodynamics, cerebral tissue oxygenation and lung gas exchange were also measured. RESULTS During right-sided capnothorax, mixed venous oxygen saturation (P = 0.018), as well as a tissue oxygenation index (P = 0.038) decreased. There was also an increase in central venous pressure (P = 0.006), and a decrease in mean arterial pressure (P = 0.045) and cardiac output (P = 0.017). During the left-sided capnothorax, the hemodynamic impairment was less than during the right side. EIT revealed that during the first period of OLV/capnothorax, no or very minor ventilation on the right side could be seen (3 ± 3% vs. 97 ± 3%, right vs. left, P = 0.007), perfusion decreased in the non-ventilated and increased in the ventilated lung (18 ± 2% vs. 82 ± 2%, right vs. left, P = 0.03). During the second OLV/capnothorax period, a similar distribution of perfusion was seen in the animals with successful separation (84 ± 4% vs. 16 ± 4%, right vs. left). CONCLUSION EIT detected in real-time dynamic changes in pulmonary ventilation and perfusion distributions. OLV to the left lung with right-sided capnothorax caused a decrease in cardiac output, arterial oxygenation and mixed venous saturation.
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Affiliation(s)
- H. REINIUS
- Hedenstierna Laboratory; Department of Surgical Sciences; Section of Anaesthesiology & Critical Care; Uppsala University; Uppsala Sweden
| | - J. B. BORGES
- Hedenstierna Laboratory; Department of Surgical Sciences; Section of Anaesthesiology & Critical Care; Uppsala University; Uppsala Sweden
- Cardio-Pulmonary Department; Pulmonary Division; Heart Institute (Incor); University of São Paulo; São Paulo Brazil
| | - F. FREDÉN
- Hedenstierna Laboratory; Department of Surgical Sciences; Section of Anaesthesiology & Critical Care; Uppsala University; Uppsala Sweden
| | - L. JIDEUS
- Department of Surgical Sciences; Section of Cardiothoracic Surgery; Uppsala University; Uppsala Sweden
| | - E. D. L. B. CAMARGO
- Department of Mechanical Engineer; Polytechnic School; University of São Paulo; São Paulo Brazil
| | - M. B. P. AMATO
- Cardio-Pulmonary Department; Pulmonary Division; Heart Institute (Incor); University of São Paulo; São Paulo Brazil
| | - G. HEDENSTIERNA
- Hedenstierna Laboratory; Department of Medical Sciences; Clinical Physiology; Uppsala University; Uppsala Sweden
| | - A. LARSSON
- Hedenstierna Laboratory; Department of Surgical Sciences; Section of Anaesthesiology & Critical Care; Uppsala University; Uppsala Sweden
| | - F. LENNMYR
- Department of Surgical Sciences; Section of Cardiothoracic Anesthesiology and Intensive Care; Uppsala University; Uppsala Sweden
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Influence of Inspiration to Expiration Ratio on Cyclic Recruitment and Derecruitment of Atelectasis in a Saline Lavage Model of Acute Respiratory Distress Syndrome*. Crit Care Med 2015; 43:e65-74. [DOI: 10.1097/ccm.0000000000000788] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
PURPOSE OF REVIEW This review article summarizes the recent advances in electrical impedance tomography (EIT) related to cardiopulmonary imaging and monitoring on the background of the 30-year development of this technology. RECENT FINDINGS EIT is expected to become a bedside tool for monitoring and guiding ventilator therapy. In this context, several studies applied EIT to determine spatial ventilation distribution during different ventilation modes and settings. EIT was increasingly combined with other signals, such as airway pressure, enabling the assessment of regional respiratory system mechanics. EIT was for the first time used prospectively to define ventilator settings in an experimental and a clinical study. Increased neonatal and paediatric use of EIT was noted. Only few studies focused on cardiac function and lung perfusion. Advanced radiological imaging techniques were applied to assess EIT performance in detecting regional lung ventilation. New approaches to improve the quality of thoracic EIT images were proposed. SUMMARY EIT is not routinely used in a clinical setting, but the interest in EIT is evident. The major task for EIT research is to provide the clinicians with guidelines how to conduct, analyse and interpret EIT examinations and combine them with other medical techniques so as to meaningfully impact the clinical decision-making.
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Monitoring Lung Volumes During Mechanical Ventilation. PEDIATRIC AND NEONATAL MECHANICAL VENTILATION 2015. [PMCID: PMC7193716 DOI: 10.1007/978-3-642-01219-8_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Respiratory inductive plethysmography (RIP) is a non-invasive method of measuring change in lung volume which is well-established as a monitor of tidal ventilation and thus respiratory patterns in sleep medicine. As RIP is leak independent, can measure end-expiratory lung volume as well as tidal volume and is applicable to both the ventilated and spontaneously breathing patient, there has been a recent interest in its use as a bedside tool in the intensive care unit.
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Assessment of respiratory system compliance with electrical impedance tomography using a positive end-expiratory pressure wave maneuver during pressure support ventilation: a pilot clinical study. Crit Care 2014; 18:679. [PMID: 25492307 PMCID: PMC4301036 DOI: 10.1186/s13054-014-0679-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/19/2014] [Indexed: 11/10/2022] Open
Abstract
Introduction Assessment of respiratory system compliance (Crs) can be used for individual optimization of positive end-expiratory pressure (PEEP). However, in patients with spontaneous breathing activity, the conventional methods for Crs measurement are inaccurate because of the variable muscular pressure of the patient. We hypothesized that a PEEP wave maneuver, analyzed with electrical impedance tomography (EIT), might be suitable for global and regional assessment of Crs during assisted spontaneous breathing. Methods After approval of the local ethics committee, we performed a pilot clinical study in 18 mechanically ventilated patients (61 ± 16 years (mean ± standard deviation)) who were suitable for weaning with pressure support ventilation (PSV). For the PEEP wave, PEEP was elevated by 1 cmH2O after every fifth breath during PSV. This was repeated five times, until a total PEEP increase of 5 cmH2O was reached. Subsequently, PEEP was reduced in steps of 1 cmH2O in the same manner until the original PEEP level was reached. Crs was calculated using EIT from the global, ventral and dorsal lung regions of interest. For reference measurements, all patients were also examined during controlled mechanical ventilation (CMV) with a low-flow pressure-volume maneuver. Global and regional Crs(low-flow) was calculated as the slope of the pressure-volume loop between the pressure that corresponded to the selected PEEP and PEEP +5 cmH2O. For additional reference, Crs during CMV (Crs(CMV)) was calculated as expired tidal volume divided by the difference between airway plateau pressure and PEEP. Results Respiratory system compliance calculated from the PEEP wave (Crs(PEEP wave)) correlated closely with both reference measurements (r = 0.79 for Crs(low-flow) and r = 0.71 for Crs(CMV)). No significant difference was observed between the mean Crs(PEEP wave) and the mean Crs(low-flow). However, a significant bias of +17.1 ml/cmH2O was observed between Crs(PEEP wave) and Crs(CMV). Conclusion Analyzing a PEEP wave maneuver with EIT allows calculation of global and regional Crs during assisted spontaneous breathing. In mechanically ventilated patients with spontaneous breathing activity, this method might be used for assessment of the global and regional mechanical properties of the respiratory system. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0679-6) contains supplementary material, which is available to authorized users.
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Borges JB, Hedenstierna G, Bergman JS, Amato MBP, Avenel J, Montmerle-Borgdorff S. First-time imaging of effects of inspired oxygen concentration on regional lung volumes and breathing pattern during hypergravity. Eur J Appl Physiol 2014; 115:353-63. [PMID: 25323531 DOI: 10.1007/s00421-014-3020-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/02/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE Aeroatelectasis can develop in aircrew flying the latest generation high-performance aircraft. Causes alleged are relative hyperoxia, increased gravity in the head-to-foot direction (+Gz), and compression of legs and stomach by anti-G trousers (AGT). We aimed to assess, in real time, the effects of hyperoxia, +Gz accelerations and AGT inflation on changes in regional lung volumes and breathing pattern evaluated in an axial plane by electrical impedance tomography (EIT). METHODS The protocol mimicked a routine peacetime flight in combat aircraft. Eight subjects wearing AGT were studied in a human centrifuge during 1 h 15 min exposure of +1 to +3.5Gz. They performed this sequence three times, breathing AIR, 44.5 % O2 or 100 % O2. Continuous recording of functional EIT enabled uninterrupted assessment of regional lung volumes at the 5th intercostal level. Breathing pattern was also monitored. RESULTS EIT data showed that +3.5Gz, compared with any moment without hypergravity, caused an abrupt decrease in regional tidal volume (VT) and regional end-expiratory lung volume (EELV) measured in the EIT slice, independently of inspired oxygen concentration. Breathing AIR or 44.5 % O2, sub-regional EELV measured in the EIT slice decreased similarly in dorsal and ventral regions, but sub-regional VT measured in the EIT slice decreased significantly more dorsally than ventrally. Breathing 100 % O2, EELV and VT decreased similarly in both regions. Inspired tidal volume increased in hyperoxia, whereas breathing frequency increased in hypergravity and hyperoxia. CONCLUSIONS Our findings suggest that hypergravity and AGT inflation cause airway closure and air trapping in gravity-dependent lung regions, facilitating absorption atelectasis formation, in particular during hyperoxia.
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Affiliation(s)
- João Batista Borges
- Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anaesthesiology & Critical Care, Uppsala University, Uppsala, Sweden,
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Zhang J, Patterson R. Variability in EIT Images of Lung Ventilation as a Function of Electrode Planes and Body Positions. Open Biomed Eng J 2014; 8:35-41. [PMID: 25110529 PMCID: PMC4126188 DOI: 10.2174/1874120701408010035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 11/22/2022] Open
Abstract
This study is aimed at investigating the variability in resistivity changes in the lung region as a function of air volume, electrode plane and body position. Six normal subjects (33.8 ± 4.7 years, range from 26 to 37 years) were studied using the Sheffield Electrical Impedance Tomography (EIT) portable system. Three transverse planes at the level of second intercostal space, the level of the xiphisternal joint, and midway between upper and lower locations were chosen for measurements. For each plane, sixteen electrodes were uniformly positioned around the thorax. Data were collected with the breath held at end expiration and after inspiring 0.5, 1.0, or 1.5 liters of air from end expiration, with the subject in both the supine and sitting position. The average resistivity change in five regions, two 8x8 pixel local regions in the right lung, entire right, entire left and total lung regions, were calculated. The results show the resistivity change averaged over electrode positions and subject positions was 7-9% per liter of air, with a slightly larger resistivity change of 10 % per liter air in the lower electrode plane. There was no significant difference (p>0.05) between supine and sitting. The two 8x8 regions show a larger inter individual variability (coefficient of variation, CV, is from 30% to 382%) compared to the entire left, entire right and total lung (CV is from 11% to 51%). The results for the global regions are more consistent. The large inter individual variability appears to be a problem for clinical applications of EIT, such as regional ventilation. The variability may be mitigated by choosing appropriate electrode plane, body position and region of interest for the analysis.
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Affiliation(s)
- Jie Zhang
- Division of Medical Physics, Department of Radiology, University of Kentucky, Lexington, KY 40536, USA
| | - Robert Patterson
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN 55455, USA
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Ushijima R, Joho S, Akabane T, Oda Y, Inoue H. Differing effects of adaptive servoventilation and continuous positive airway pressure on muscle sympathetic nerve activity in patients with heart failure. Circ J 2014; 78:1387-95. [PMID: 24705391 DOI: 10.1253/circj.cj-13-1468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Long-term adaptive servoventilation (ASV) increases cardiac function more effectively than continuous positive airway pressure (CPAP), possibly via alleviation of sympathetic overactivation. The present study evaluated the effect of ASV and CPAP at comparable pressure on muscle sympathetic nerve activity (MSNA) in patients with heart failure (HF) and with or without periodic breathing (PB). METHODS AND RESULTS A total of 57 patients with HF (ejection fraction <0.45) were randomized to receive CPAP (n=28) or ASV (n=29). Respiratory profiles and MSNA were continuously monitored before and during CPAP and ASV (30min) at pressures of 6.5 and 6.6cmH2O, respectively. The severity of respiratory instability was determined using the coefficient of variation of tidal volume (CV-TV). Although heart rate and blood pressure remained unchanged, only ASV improved CV-TV. MSNA decreased in the ASV (P<0.001), but not in the CPAP group. The change in CV-TV independently predicted changes in MSNA (P<0.001). Device type and PB significantly interacted with changes in MSNA (P<0.05) and ASV exerted sympathoinhibitory effects in patients with PB, whereas CPAP did not. A sympathoinhibitory effect in patients without PB was not evident in either treatment arm. CONCLUSIONS ASV probably exerts its sympathoinhibitory effects in patients with HF and PB through pressure support.
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Karsten J, Meier T, Iblher P, Schindler A, Paarmann H, Heinze H. The suitability of EIT to estimate EELV in a clinical trial compared to oxygen wash-in/wash-out technique. ACTA ACUST UNITED AC 2014; 59:59-64. [DOI: 10.1515/bmt-2012-0076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 08/30/2013] [Indexed: 11/15/2022]
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Elke G, Fuld MK, Halaweish AF, Grychtol B, Weiler N, Hoffman EA, Frerichs I. Quantification of ventilation distribution in regional lung injury by electrical impedance tomography and xenon computed tomography. Physiol Meas 2013; 34:1303-18. [DOI: 10.1088/0967-3334/34/10/1303] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Effect of PEEP and tidal volume on ventilation distribution and end-expiratory lung volume: a prospective experimental animal and pilot clinical study. PLoS One 2013; 8:e72675. [PMID: 23991138 PMCID: PMC3750001 DOI: 10.1371/journal.pone.0072675] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 07/18/2013] [Indexed: 11/19/2022] Open
Abstract
Introduction Lung-protective ventilation aims at using low tidal volumes (VT) at optimum positive end-expiratory pressures (PEEP). Optimum PEEP should recruit atelectatic lung regions and avoid tidal recruitment and end-inspiratory overinflation. We examined the effect of VT and PEEP on ventilation distribution, regional respiratory system compliance (CRS), and end-expiratory lung volume (EELV) in an animal model of acute lung injury (ALI) and patients with ARDS by using electrical impedance tomography (EIT) with the aim to assess tidal recruitment and overinflation. Methods EIT examinations were performed in 10 anaesthetized pigs with normal lungs ventilated at 5 and 10 ml/kg body weight VT and 5 cmH2O PEEP. After ALI induction, 10 ml/kg VT and 10 cmH2O PEEP were applied. Afterwards, PEEP was set according to the pressure-volume curve. Animals were randomized to either low or high VT ventilation changed after 30 minutes in a crossover design. Ventilation distribution, regional CRS and changes in EELV were analyzed. The same measures were determined in five ARDS patients examined during low and high VT ventilation (6 and 10 (8) ml/kg) at three PEEP levels. Results In healthy animals, high compared to low VT increased CRS and ventilation in dependent lung regions implying tidal recruitment. ALI reduced CRS and EELV in all regions without changing ventilation distribution. Pressure-volume curve-derived PEEP of 21±4 cmH2O (mean±SD) resulted in comparable increase in CRS in dependent and decrease in non-dependent regions at both VT. This implied that tidal recruitment was avoided but end-inspiratory overinflation was present irrespective of VT. In patients, regional CRS differences between low and high VT revealed high degree of tidal recruitment and low overinflation at 3±1 cmH2O PEEP. Tidal recruitment decreased at 10±1 cmH2O and was further reduced at 15±2 cmH2O PEEP. Conclusions Tidal recruitment and end-inspiratory overinflation can be assessed by EIT-based analysis of regional CRS.
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Pulletz S, Kott M, Elke G, Schädler D, Vogt B, Weiler N, Frerichs I. Dynamics of regional lung aeration determined by electrical impedance tomography in patients with acute respiratory distress syndrome. Multidiscip Respir Med 2012; 7:44. [PMID: 23153321 PMCID: PMC3528404 DOI: 10.1186/2049-6958-7-44] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/31/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Lung tissue of patients with acute respiratory distress syndrome (ARDS) is heterogeneously damaged and prone to develop atelectasis. During inflation, atelectatic regions may exhibit alveolar recruitment accompanied by prolonged filling with air in contrast to regions with already open alveoli with a fast increase in regional aeration. During deflation, derecruitment of injured regions is possible with ongoing loss in regional aeration. The aim of our study was to assess the dynamics of regional lung aeration in mechanically ventilated patients with ARDS and its dependency on positive end-expiratory pressure (PEEP) using electrical impedance tomography (EIT). METHODS Twelve lung healthy and twenty ARDS patients were examined by EIT during sustained step increases in airway pressure from 0, 8 and 15 cm H2O to 35 cm H2O and during subsequent step decrease to the corresponding PEEP. Regional EIT waveforms in the ventral and dorsal lung regions were fitted to bi-exponential equations. Regional fast and slow respiratory time constants and the sizes of the fast and slow compartments were subsequently calculated. RESULTS ARDS patients exhibited significantly lower fast and slow time constants than the lung healthy patients in ventral and dorsal regions. The time constants were significantly affected by PEEP and differed between the regions. The size of the fast compartment was significantly lower in ARDS patients than in patients with healthy lung under all studied conditions. CONCLUSION These results show that regional lung mechanics can be assessed by EIT. They reflect the lower respiratory system compliance of injured lungs and imply more pronounced regional recruitment and derecruitment in ARDS patients.
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Affiliation(s)
- Sven Pulletz
- Department of Anaesthesiology and Intensive Care Medicine, Klinikum Osnabrück, Am Finkenhügel 1, 49076 Osnabrück, Germany.
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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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Vogt B, Pulletz S, Elke G, Zhao Z, Zabel P, Weiler N, Frerichs I. Spatial and temporal heterogeneity of regional lung ventilation determined by electrical impedance tomography during pulmonary function testing. J Appl Physiol (1985) 2012; 113:1154-61. [PMID: 22898553 DOI: 10.1152/japplphysiol.01630.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrical impedance tomography (EIT) is a functional imaging modality capable of tracing continuously regional pulmonary gas volume changes. The aim of our study was to determine if EIT was able to assess spatial and temporal heterogeneity of ventilation during pulmonary function testing in 14 young (37 ± 10 yr, mean age ± SD) and 12 elderly (71 ± 9 yr) subjects without lung disease and in 33 patients with chronic obstructive pulmonary disease (71 ± 9 yr). EIT and spirometry examinations were performed during tidal breathing and a forced vital capacity (FVC) maneuver preceded by full inspiration to total lung capacity. Regional inspiratory vital capacity (IVC); FVC; forced expiratory volume in 1 s (FEV(1)); FEV(1)/FVC; times required to expire 25%, 50%, 75%, and 90% of FVC (t(25), t(50), t(75), t(90)); and tidal volume (V(T)) were determined in 912 EIT image pixels in the chest cross section. Coefficients of variation (CV) were calculated from all pixel values of IVC, FVC, FEV(1), and V(T) to characterize the ventilation heterogeneity. The highest values were found in patients, and no differences existed between the healthy young and elderly subjects. Receiver-operating characteristics curves showed that CV of regional IVC, FVC, FEV(1), and V(T) discriminated the young and elderly subjects from the patients. Frequency distributions of pixel FEV(1)/FVC, t(25), t(50), t(75), and t(90) identified the highest ventilation heterogeneity in patients but distinguished also the healthy young from the elderly subjects. These results indicate that EIT may provide additional information during pulmonary function testing and identify pathologic and age-related spatial and temporal heterogeneity of regional lung function.
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Affiliation(s)
- Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Kiel, Germany
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Bodenstein M, Wang H, Boehme S, Vogt A, Kwiecien R, David M, Markstaller K. Influence of crystalloid and colloid fluid infusion and blood withdrawal on pulmonary bioimpedance in an animal model of mechanical ventilation. Physiol Meas 2012; 33:1225-36. [PMID: 22735353 DOI: 10.1088/0967-3334/33/7/1225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electrical impedance tomography (EIT) is considered useful for monitoring regional ventilation and aeration in intensive-care patients during mechanical ventilation. Changes in their body fluid state modify the electrical properties of lung tissue and may interfere with the EIT measurements of lung aeration. The aim of our study was to assess the effects of crystalloid and colloid infusion and blood withdrawal on bioimpedance determined by EIT in a chest cross-section. Fourteen anaesthetized mechanically ventilated pigs were subjected to interventions affecting the volume state (crystalloid and colloid infusion, blood withdrawal). Six animals received additional crystalloid fluids (fluid group) whereas eight did not (no-fluid group). Global and regional relative impedance changes (RIC, dimensionless unit) were determined by backprojection at end-expiration. Regional ventilation distribution was analyzed by calculating the tidal RIC in the same regions. Colloid infusion led to a significant fall in the global end-expiratory RIC (mean differences: fluid: -91.2, p < 0.001, no-fluid: -38.9, p < 0.001), which was partially reversed after blood withdrawal (mean differences, fluid: +45.1, p = 0.047 and no-fluid: +26.2, p = 0.009). The RIC was significantly lower in the animals with additional crystalloids (mean group difference: 45.5, p < 0.001). Global and regional tidal volumes were not significantly affected by the fluid and volume states.
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Affiliation(s)
- Marc Bodenstein
- Department of Anaesthesiology, University Medical Centre, 55101 Mainz, Germany.
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Adler A, Amato MB, Arnold JH, Bayford R, Bodenstein M, Böhm SH, Brown BH, Frerichs I, Stenqvist O, Weiler N, Wolf GK. Whither lung EIT: Where are we, where do we want to go and what do we need to get there? Physiol Meas 2012; 33:679-94. [DOI: 10.1088/0967-3334/33/5/679] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Karsten J, Luepschen H, Grossherr M, Bruch HP, Leonhardt S, Gehring H, Meier T. Effect of PEEP on regional ventilation during laparoscopic surgery monitored by electrical impedance tomography. Acta Anaesthesiol Scand 2011; 55:878-86. [PMID: 21658014 DOI: 10.1111/j.1399-6576.2011.02467.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Anesthesia per se and pneumoperitoneum during laparoscopic surgery lead to atelectasis and impairment of oxygenation. We hypothesized that a ventilation with positive end-expiratory pressure (PEEP) during general anesthesia and laparoscopic surgery leads to a more homogeneous ventilation distribution as determined by electrical impedance tomography (EIT). Furthermore, we supposed that PEEP ventilation in lung-healthy patients would improve the parameters of oxygenation and respiratory compliance. METHODS Thirty-two patients scheduled to undergo laparoscopic cholecystectomy were randomly assigned to be ventilated with ZEEP (0 cmH(2)O) or with PEEP (10 cmH(2)O) and a subsequent recruitment maneuver. Differences in regional ventilation were analyzed by the EIT-based center-of-ventilation index (COV), which quantifies the distribution of ventilation and indicates ventilation shifts. RESULTS Higher amount of ventilation was examined in the dorsal parts of the lungs in the PEEP group. Throughout the application of PEEP, a lower shift of ventilation was found, whereas after the induction of anesthesia, a remarkable ventral shift of ventilation in ZEEP-ventilated patients (COV: ZEEP, 40.6 ± 2.4%; PEEP, 46.5 ± 3.5%; P<0.001) was observed. Compared with the PEEP group, ZEEP caused a ventral misalignment of ventilation during pneumoperitoneum (COV: ZEEP, 41.6 ± 2.4%; PEEP, 44 ± 2.7%; P=0.013). Throughout the study, there were significant differences in the parameters of oxygenation and respiratory compliance with improved values in PEEP-ventilated patients. CONCLUSION The effect of anesthesia, pneumoperitoneum, and different PEEP levels can be evaluated by EIT-based COV monitoring. An initial recruitment maneuver and a PEEP of 10 cmH(2)O preserved homogeneous regional ventilation during laparoscopic surgery in most, but not all, patients and improved oxygenation and respiratory compliance.
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Affiliation(s)
- J Karsten
- Department of Anesthesiology, University of Lübeck, Lübeck, Germany
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