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Chung CR, Ko RE, Jang GY, Lee K, Suh GY, Kim Y, Woo EJ. Comparison of noninvasive cardiac output and stroke volume measurements using electrical impedance tomography with invasive methods in a swine model. Sci Rep 2024; 14:2962. [PMID: 38316842 PMCID: PMC10844629 DOI: 10.1038/s41598-024-53488-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 02/01/2024] [Indexed: 02/07/2024] Open
Abstract
Pulmonary artery catheterization (PAC) has been used as a clinical standard for cardiac output (CO) measurements on humans. On animals, however, an ultrasonic flow sensor (UFS) placed around the ascending aorta or pulmonary artery can measure CO and stroke volume (SV) more accurately. The objective of this paper is to compare CO and SV measurements using a noninvasive electrical impedance tomography (EIT) device and three invasive devices using UFS, PAC-CCO (continuous CO) and arterial pressure-based CO (APCO). Thirty-two pigs were anesthetized and mechanically ventilated. A UFS was placed around the pulmonary artery through thoracotomy in 11 of them, while the EIT, PAC-CCO and APCO devices were used on all of them. Afterload and contractility were changed pharmacologically, while preload was changed through bleeding and injection of fluid or blood. Twenty-three pigs completed the experiment. Among 23, the UFS was used on 7 pigs around the pulmonary artery. The percentage error (PE) between COUFS and COEIT was 26.1%, and the 10-min concordance was 92.5%. Between SVUFS and SVEIT, the PE was 24.8%, and the 10-min concordance was 94.2%. On analyzing the data from all 23 pigs, the PE between time-delay-adjusted COPAC-CCO and COEIT was 34.6%, and the 10-min concordance was 81.1%. Our results suggest that the performance of the EIT device in measuring dynamic changes of CO and SV on mechanically-ventilated pigs under different cardiac preload, afterload and contractility conditions is at least comparable to that of the PAC-CCO device. Clinical studies are needed to evaluate the utility of the EIT device as a noninvasive hemodynamic monitoring tool.
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Affiliation(s)
- Chi Ryang Chung
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ryoung Eun Ko
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Geuk Young Jang
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea
| | - Kyounghun Lee
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea
| | - Gee Young Suh
- Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yongmin Kim
- Department of Convergence IT Engineering, POSTECH, Pohang, Korea
| | - Eung Je Woo
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Korea.
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Real-Time Measurements of Relative Tidal Volume and Stroke Volume Using Electrical Impedance Tomography with Spatial Filters: A Feasibility Study in a Swine Model Under Normal and Reduced Ventilation. Ann Biomed Eng 2023; 51:394-409. [PMID: 35960417 DOI: 10.1007/s10439-022-03040-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 07/28/2022] [Indexed: 01/25/2023]
Abstract
Continuous monitoring of both hemodynamic and respiratory parameters would be beneficial to patients, e.g., those in intensive care unit. The objective of this exploratory animal study was to test the feasibility of simultaneous measurements of relative tidal volume (rTV) and relative stroke volume (rSV) using an electrical impedance tomography (EIT) device equipped with a new real-time source separation algorithm implemented as two spatial filters. Five pigs were anesthetized and mechanically ventilated. The supplied tidal volume from a mechanical ventilator was reduced to 70, 50 and 30% from the 100% normal volume to simulate hypoventilation. The respiratory volume signal and cardiac volume signal were generated by applying the spatial filters to the acquired EIT data, from which values of rTV and rSV were extracted. The measured rTV values were compared with the TV values from the mechanical ventilator using the four-quadrant concordance analysis method. For changes in TV, the concordance rate in each animal ranged from 81.8% to 100%, while it was 92.5% when the data from all five animals were pooled together. When the measured rTV values for each animal were scaled to the absolute TVEIT values in mL using the TVVent data from the mechanical ventilator, the smallest 95% limits of agreement (LoA) were - 6.04 and 7.44 mL for the 70% ventilation level, and the largest 95% LoA were - 18.1 and 19.4 mL for the 50% ventilation level. The percentage error between TVEIT and TVVent was 10.3%. Although similar statistical analyses on rSV data could not be performed due to limited intra-animal variability, changes in rSV values measured by the EIT device were comparable to those measured by an invasive hemodynamic monitor. In this animal study, we were able to demonstrate the feasibility of an EIT device for noninvasive and simultaneous measurements of rTV and rSV in real time. However, the performance of the real-time source separation method needs to be further validated on animals and human subjects, particularly over a wide range of SV values. Future clinical studies are needed to assess the potential usefulness of the new method in dynamic cardiopulmonary monitoring and explore other clinical applications.
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Behem CR, Graessler MF, Friedheim T, Kluttig R, Pinnschmidt HO, Duprée A, Debus ES, Reuter DA, Wipper SH, Trepte CJC. The use of pulse pressure variation for predicting impairment of microcirculatory blood flow. Sci Rep 2021; 11:9215. [PMID: 33911116 PMCID: PMC8080713 DOI: 10.1038/s41598-021-88458-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/12/2021] [Indexed: 02/07/2023] Open
Abstract
Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg−1 bodyweight−1. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min−1) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.
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Affiliation(s)
- Christoph R Behem
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
| | - Michael F Graessler
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Till Friedheim
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Rahel Kluttig
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Hans O Pinnschmidt
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Duprée
- Department of Visceral- and Thoracic Surgery, Center of Operative Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - E Sebastian Debus
- Department of Vascular Medicine, University Heart and Vascular Center Hamburg GmbH (UHZ), Hamburg, Germany
| | - Daniel A Reuter
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Sabine H Wipper
- University Department for Vascular Surgery, Department of Operative Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Constantin J C Trepte
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
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Hovnanian ALD, Costa ELV, Hoette S, Fernandes CJCS, Jardim CVP, Dias BA, Morinaga LTK, Amato MBP, Souza R. Electrical impedance tomography in pulmonary arterial hypertension. PLoS One 2021; 16:e0248214. [PMID: 33730110 PMCID: PMC7968654 DOI: 10.1371/journal.pone.0248214] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
The characterization of pulmonary arterial hypertension (PAH) relies mainly on right heart catheterization (RHC). Electrical impedance tomography (EIT) provides a non-invasive estimation of lung perfusion that could complement the hemodynamic information from RHC. To assess the association between impedance variation of lung perfusion (ΔZQ) and hemodynamic profile, severity, and prognosis, suspected of PAH or worsening PAH patients were submitted simultaneously to RHC and EIT. Measurements of ΔZQ were obtained. Based on the results of the RHC, 35 patients composed the PAH group, and eight patients, the normopressoric (NP) group. PAH patients showed a significantly reduced ΔZQ compared to the NP group. There was a significant correlation between ΔZQ and hemodynamic parameters, particularly with stroke volume (SV) (r = 0.76; P < 0.001). At 60 months, 15 patients died (43%) and 1 received lung transplantation; at baseline they had worse hemodynamics, and reduced ΔZQ when compared to survivors. Patients with low ΔZQ (≤154.6%.Kg) presented significantly worse survival (P = 0.033). ΔZQ is associated with hemodynamic status of PAH patients, with disease severity and survival, demonstrating EIT as a promising tool for monitoring patients with pulmonary vascular disease.
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Affiliation(s)
- André L. D. Hovnanian
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
- * E-mail:
| | - Eduardo L. V. Costa
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Susana Hoette
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Caio J. C. S. Fernandes
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Carlos V. P. Jardim
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Bruno A. Dias
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Luciana T. K. Morinaga
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Marcelo B. P. Amato
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
| | - Rogério Souza
- Pulmonary Divison, Heart Institute, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil
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Prediction of Fluid Responsiveness by Stroke Volume Variation in Children Undergoing Fontan Operation. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2595960. [PMID: 33224977 PMCID: PMC7669329 DOI: 10.1155/2020/2595960] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 10/19/2020] [Accepted: 10/28/2020] [Indexed: 11/17/2022]
Abstract
Background Fontan operation is a palliative medical procedure performed on children with single-ventricle defects. As postoperative success of the procedure largely depends on the preload volume, it is necessary to maintain an appropriate pressure gradient between the systemic vein and the left atrium to ensure the effective volume of systemic circulation. However, there is a lack of effective indexes to evaluate fluid responsiveness in Fontan patients. Stroke volume variation (SVV) is a dynamic hemodynamic parameter based on cardiopulmonary interaction in mechanical ventilation. This study is aimed at validating the sensitivity and specificity of SVV and central venous pressure (CVP) in assessing the fluid responsiveness of Fontan patients. Method Sixty-four children with single ventricle who underwent modified Fontan operation between May 2018 and January 2020 were included in this study. Patients were administered 10 ml·kg−1 albumin for fluid challenge within 10 min after cardiopulmonary bypass. Before and after fluid challenge, the invasive arterial pressure module was connected to MostCare™ equipment to collect the cardiac index (CI) and SVV dynamically in a time window of 30 s at a frequency of 1000 Hz. According to the range of CI change, patients with ΔCI ≥ 15% were classified into the responder (R) group and those with ΔCI < 15% into the nonresponder (NR) group. Using SVV and CVP as indicators, the receiver operating characteristic (ROC) curve of the patients was established, and the area under curve (AUC), diagnostic threshold, sensitivity, and specificity were calculated. Results The SVV values were 16.28% (25th and 75th percentiles 14.17%-19.24%) and 13.68% (25th and 75th percentiles 12.90%-15.89%) before and after fluid challenge treatment in responders, respectively, and the values were 18.60 ± 1.83 mmHg before and 20.20 ± 2.39 mmHg for CVP after treatment. The AUC of SVV was 0.74 (95% confidence interval (CI) 0.54-0.94, P < 0.05), and the cutoff value was 16%, offering a sensitivity of 50% and a specificity of 91.7%. Meanwhile, the AUC of CVP was 0.70 (95% CI 0.50-0.92, P > 0.05), and the cutoff value was 19.5 mmHg, offering a sensitivity of 58% and a specificity of 76%. Conclusion SVV exhibited a good predictive value for fluid responsiveness in pediatric Fontan patients. Appropriate fluid therapy according to SVV could improve the cardiac function of such patients. Trial registration. This study was registered in Chinese Clinical Trail Registry on Jan 26, 2018. Registration number is ChiCTR1800014654. Registry URL is http://www.chictr.org.cn/showproj.aspx?proj=25019. This observational prospective study was approved by the Local Ethics Committee of Shanghai Children's Medical Center affiliated to Shanghai Jiao Tong University (SCMCIRB-K2017035).
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Borges JB, Alcala GC, Mlček M. A Step Forward toward a Bedside and Timely Monitoring of Regional [Formula: see text]/[Formula: see text] Matching. Am J Respir Crit Care Med 2020; 202:1342-1344. [PMID: 32833499 PMCID: PMC7667916 DOI: 10.1164/rccm.202007-2896ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
| | | | - Mikuláš Mlček
- Institute of PhysiologyCharles UniversityPrague, Czech Republicand
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Popková M, Kuriščák E, Hála P, Janák D, Tejkl L, Bělohlávek J, Ošťádal P, Neužil P, Kittnar O, Mlček M. Increasing veno-arterial extracorporeal membrane oxygenation flow reduces electrical impedance of the lung regions in porcine acute heart failure. Physiol Res 2020; 69:609-620. [DOI: 10.33549/physiolres.934429] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a technique used in patients with severe heart failure. The aim of this study was to evaluate its effects on left ventricular afterload and fluid accumulation in lungs with electrical impedance tomography (EIT). In eight swine, incremental increases of extracorporeal blood flow (EBF) were applied before and after the induction of ischemic heart failure. Hemodynamic parameters were continuously recorded and computational analysis of EIT was used to determine lung fluid accumulation. With an increase in EBF from 1 to 4 l/min in acute heart failure the associated increase of arterial pressure (raised by 44 %) was accompanied with significant decrease of electrical impedance of lung regions. Increasing EBF in healthy circulation did not cause lung impedance changes. Our findings indicate that in severe heart failure EIT may reflect fluid accumulation in lungs due to increasing EBF.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - M Mlček
- Department of Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Zhang N, Jiang H, Zhang C, Li Q, Li Y, Zhang B, Deng J, Niu G, Yang B, Frerichs I, Moeller K, Fu F, Zhao Z. The influence of an electrical impedance tomography belt on lung function determined by spirometry in sitting position. Physiol Meas 2020; 41:044002. [PMID: 32160596 DOI: 10.1088/1361-6579/ab7edb] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The aim of the study was to examine whether an electrical impedance tomography (EIT) electrode belt changed the lung function in healthy volunteers and patients with respiratory muscle weakness (RMW) and chronic obstructive pulmonary disease (COPD). APPROACH In total, thirty subjects were included (10 healthy volunteers, 10 subjects with RMW, maximum inspiratory pressure < 40 cmH2O, and 10 COPD, grade I-IV). Spirometry measurements were conducted in a sitting position once a day at similar times on two consecutive days. Slow expiratory vital capacity (VC), forced vital capacity (FVC) and maximum voluntary ventilation (MVV) manoeuvres were performed. On day 1, spirometry was performed without the EIT electrode belt, and on day 2, the belt was attached to the thorax. MAIN RESULTS Lung function was not influenced by the electrode belt in healthy subjects. The test-retest reliability in the healthy group was 0.89, 0.89 and 0.85 for VC, FVC and MVV, respectively. On the other hand, all investigated parameters were significantly decreased in the RMW group (VC, 51.3 ± 18.0 versus 46.5 ± 18.0% predicted, without versus with EIT belt, p< 0.01; FVC, 51.7 ± 19.0 versus 45.8 ± 18.1% predicted, p< 0.01; MVV, 41.0 ± 20.0 versus 38.8 ± 19.6% predicted, p< 0.01). VC and MVV also decreased significantly in the COPD group (VC, 77.4 ± 20.5 versus 74.6 ± 18.8% predicted, p< 0.05; MVV, 57.4 ± 15.7 versus 54.4 ± 12.5% predicted, p< 0.05). SIGNIFICANCE An EIT electrode belt could reduce lung volumes in subjects with pre-existing lung diseases. Comparing lung function acquired with an electrode belt to corresponding values obtained without the belt should be avoided.
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Affiliation(s)
- Na Zhang
- Department of Respiratory Rehabilitation Center, Beijing Rehabilitation Hospital of Capital Medical University, Xixiazhuang, Badachu, Shijingshan, Beijing 100114, People's Republic of China. Na Zhang and Hongying Jiang contributed equally to this work
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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: 3] [Impact Index Per Article: 0.6] [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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Spinelli E, Mauri T, Fogagnolo A, Scaramuzzo G, Rundo A, Grieco DL, Grasselli G, Volta CA, Spadaro S. Electrical impedance tomography in perioperative medicine: careful respiratory monitoring for tailored interventions. BMC Anesthesiol 2019; 19:140. [PMID: 31390977 PMCID: PMC6686519 DOI: 10.1186/s12871-019-0814-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/29/2019] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Electrical impedance tomography (EIT) is a non-invasive radiation-free monitoring technique that provides images based on tissue electrical conductivity of the chest. Several investigations applied EIT in the context of perioperative medicine, which is not confined to the intraoperative period but begins with the preoperative assessment and extends to postoperative follow-up. MAIN BODY EIT could provide careful respiratory monitoring in the preoperative assessment to improve preparation for surgery, during anaesthesia to guide optimal ventilation strategies and to monitor the hemodynamic status and in the postoperative period for early detection of respiratory complications. Moreover, EIT could further enhance care of patients undergoing perioperative diagnostic procedures. This narrative review summarizes the latest evidence on the application of this technique to the surgical patient, focusing also on possible future perspectives. CONCLUSIONS EIT is a promising technique for the perioperative assessment of surgical patients, providing tailored adaptive respiratory and haemodynamic monitoring. Further studies are needed to address the current technological limitations, confirm the findings and evaluate which patients can benefit more from this technology.
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Affiliation(s)
- Elena Spinelli
- Dipartimento di Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli studi di Milano, Milan, Italy
| | - Tommaso Mauri
- Dipartimento di Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli studi di Milano, Milan, Italy
| | - Alberto Fogagnolo
- Department Morphology, Surgery and Experimental medicine, Anesthesia and Intensive care section, University of Ferrara, Azienda Ospedaliera- Universitaria Sant'Anna, 8, Aldo Moro, Ferrara, Italy
| | - Gaetano Scaramuzzo
- Department Morphology, Surgery and Experimental medicine, Anesthesia and Intensive care section, University of Ferrara, Azienda Ospedaliera- Universitaria Sant'Anna, 8, Aldo Moro, Ferrara, Italy
| | - Annalisa Rundo
- UOC Anestesia e Rianimazione, Polo ospedaliero Belcolle ASL, Viterbo, Italy
| | - Domenico Luca Grieco
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of the Sacred Heart, Fondazione "Policlinico Universitario A. Gemelli", Rome, Italy
| | - Giacomo Grasselli
- Dipartimento di Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Università degli studi di Milano, Milan, Italy
| | - Carlo Alberto Volta
- Department Morphology, Surgery and Experimental medicine, Anesthesia and Intensive care section, University of Ferrara, Azienda Ospedaliera- Universitaria Sant'Anna, 8, Aldo Moro, Ferrara, Italy
| | - Savino Spadaro
- Department Morphology, Surgery and Experimental medicine, Anesthesia and Intensive care section, University of Ferrara, Azienda Ospedaliera- Universitaria Sant'Anna, 8, Aldo Moro, Ferrara, Italy.
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Tomicic V, Cornejo R. Lung monitoring with electrical impedance tomography: technical considerations and clinical applications. J Thorac Dis 2019; 11:3122-3135. [PMID: 31463141 DOI: 10.21037/jtd.2019.06.27] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In recent years there has been substantial progress in the imaging evaluation of patients with lung disease requiring mechanical ventilatory assistance. This has been demonstrated by the inclusion of pulmonary ultrasound, positron emission tomography, electrical impedance tomography (EIT), and magnetic resonance imaging (MRI). The EIT uses electric current to evaluate the distribution of alternating current conductivity within the thoracic cavity. The advantage of the latter is that it is non-invasive, bedside radiation-free functional imaging modality for continuous monitoring of lung ventilation and perfusion. EIT can detect recruitment or derecruitment, overdistension, variation of poorly ventilated lung units (silent spaces), and pendelluft phenomenon in spontaneously breathing patients. In addition, the regional expiratory time constants have been recently explored.
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Affiliation(s)
- Vinko Tomicic
- Jefe Unidad de Cuidados Intensivos Respiratorios, Clínica Indisa, Universidad Andres Bello, Santiago, Chile
| | - Rodrigo Cornejo
- Jefe Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Chile
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Bachmann MC, Morais C, Bugedo G, Bruhn A, Morales A, Borges JB, Costa E, Retamal J. Electrical impedance tomography in acute respiratory distress syndrome. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2018; 22:263. [PMID: 30360753 PMCID: PMC6203288 DOI: 10.1186/s13054-018-2195-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/14/2018] [Indexed: 12/29/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a clinical entity that acutely affects the lung parenchyma, and is characterized by diffuse alveolar damage and increased pulmonary vascular permeability. Currently, computed tomography (CT) is commonly used for classifying and prognosticating ARDS. However, performing this examination in critically ill patients is complex, due to the need to transfer these patients to the CT room. Fortunately, new technologies have been developed that allow the monitoring of patients at the bedside. Electrical impedance tomography (EIT) is a monitoring tool that allows one to evaluate at the bedside the distribution of pulmonary ventilation continuously, in real time, and which has proven to be useful in optimizing mechanical ventilation parameters in critically ill patients. Several clinical applications of EIT have been developed during the last years and the technique has been generating increasing interest among researchers. However, among clinicians, there is still a lack of knowledge regarding the technical principles of EIT and potential applications in ARDS patients. The aim of this review is to present the characteristics, technical concepts, and clinical applications of EIT, which may allow better monitoring of lung function during ARDS.
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Affiliation(s)
- M Consuelo Bachmann
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Acute Respiratory and Critical Illness Center (ARCI), Santiago, Chile
| | - Caio Morais
- Divisao de Pneumologia, Instituto do Coracao (Incor), Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Guillermo Bugedo
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Acute Respiratory and Critical Illness Center (ARCI), Santiago, Chile
| | - Alejandro Bruhn
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Acute Respiratory and Critical Illness Center (ARCI), Santiago, Chile
| | - Arturo Morales
- Departamento Enfermedades Respiratorias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - João B Borges
- Divisao de Pneumologia, Instituto do Coracao (Incor), Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.,Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Uppsala University, Uppsala, Sweden
| | - Eduardo Costa
- Divisao de Pneumologia, Instituto do Coracao (Incor), Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Jaime Retamal
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile. .,Acute Respiratory and Critical Illness Center (ARCI), Santiago, Chile.
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Wodack KH, Buehler S, Nishimoto SA, Graessler MF, Behem CR, Waldmann AD, Mueller B, Böhm SH, Kaniusas E, Thürk F, Maerz A, Trepte CJC, Reuter DA. Detection of thoracic vascular structures by electrical impedance tomography: a systematic assessment of prominence peak analysis of impedance changes. Physiol Meas 2018; 39:024002. [PMID: 29350189 DOI: 10.1088/1361-6579/aaa924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside monitoring technology, primarily used to monitor lung function. First experimental data shows that the descending aorta can be detected at different thoracic heights and might allow the assessment of central hemodynamics, i.e. stroke volume and pulse transit time. APPROACH First, the feasibility of localizing small non-conductive objects within a saline phantom model was evaluated. Second, this result was utilized for the detection of the aorta by EIT in ten anesthetized pigs with comparison to thoracic computer tomography (CT). Two EIT belts were placed at different thoracic positions and a bolus of hypertonic saline (10 ml, 20%) was administered into the ascending aorta while EIT data were recorded. EIT images were reconstructed using the GREIT model, based on the individual's thoracic contours. The resulting EIT images were analyzed pixel by pixel to identify the aortic pixel, in which the bolus caused the highest transient impedance peak in time. MAIN RESULTS In the phantom, small objects could be located at each position with a maximal deviation of 0.71 cm. In vivo, no significant differences between the aorta position measured by EIT and the anatomical aorta location were obtained for both measurement planes if the search was restricted to the dorsal thoracic region of interest (ROIs). SIGNIFICANCE It is possible to detect the descending aorta at different thoracic levels by EIT using an intra-aortic bolus of hypertonic saline. No significant differences in the position of the descending aorta on EIT images compared to CT images were obtained for both EIT belts.
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Affiliation(s)
- K H Wodack
- Department of Anesthesiology, Center of Anaesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Author to whom any correspondence should be addressed
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Braun F, Proença M, Adler A, Riedel T, Thiran JP, Solà J. Accuracy and reliability of noninvasive stroke volume monitoring via ECG-gated 3D electrical impedance tomography in healthy volunteers. PLoS One 2018; 13:e0191870. [PMID: 29373611 PMCID: PMC5786320 DOI: 10.1371/journal.pone.0191870] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/12/2018] [Indexed: 01/31/2023] Open
Abstract
Cardiac output (CO) and stroke volume (SV) are parameters of key clinical interest. Many techniques exist to measure CO and SV, but are either invasive or insufficiently accurate in clinical settings. Electrical impedance tomography (EIT) has been suggested as a noninvasive measure of SV, but inconsistent results have been reported. Our goal is to determine the accuracy and reliability of EIT-based SV measurements, and whether advanced image reconstruction approaches can help to improve the estimates. Data were collected on ten healthy volunteers undergoing postural changes and exercise. To overcome the sensitivity to heart displacement and thorax morphology reported in previous work, we used a 3D EIT configuration with 2 planes of 16 electrodes and subject-specific reconstruction models. Various EIT-derived SV estimates were compared to reference measurements derived from the oxygen uptake. Results revealed a dramatic impact of posture on the EIT images. Therefore, the analysis was restricted to measurements in supine position under controlled conditions (low noise and stable heart and lung regions). In these measurements, amplitudes of impedance changes in the heart and lung regions could successfully be derived from EIT using ECG gating. However, despite a subject-specific calibration the heart-related estimates showed an error of 0.0 ± 15.2 mL for absolute SV estimation. For trending of relative SV changes, a concordance rate of 80.9% and an angular error of -1.0 ± 23.0° were obtained. These performances are insufficient for most clinical uses. Similar conclusions were derived from lung-related estimates. Our findings indicate that the key difficulty in EIT-based SV monitoring is that purely amplitude-based features are strongly influenced by other factors (such as posture, electrode contact impedance and lung or heart conductivity). All the data of the present study are made publicly available for further investigations.
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Affiliation(s)
- Fabian Braun
- Systems Division, Centre Suisse d’Electronique et de Microtechnique (CSEM), CH-2002 Neuchâtel, Switzerland
- Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- * E-mail:
| | - Martin Proença
- Systems Division, Centre Suisse d’Electronique et de Microtechnique (CSEM), CH-2002 Neuchâtel, Switzerland
- Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Andy Adler
- Systems and Computer Engineering, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Thomas Riedel
- Cantonal Hospital Graubuenden, CH-7000 Chur, Switzerland
- University Children’s Hospital and University of Bern, CH-3010 Bern, Switzerland
| | - Jean-Philippe Thiran
- Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Department of Radiology, University Hospital Center (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
| | - Josep Solà
- Systems Division, Centre Suisse d’Electronique et de Microtechnique (CSEM), CH-2002 Neuchâtel, Switzerland
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