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The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome

BACKGROUND: The electrical impedance tomography (EIT)-based global inhomogeneity (GI) index was introduced to quantify tidal volume distribution within the lung. Up to now, the GI index was evaluated for plausibility but the analysis of how it is influenced by various physiological factors is still...

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Autores principales: Zhao, Zhanqi, Pulletz, Sven, Frerichs, Inéz, Müller-Lisse, Ullrich, Möller, Knut
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3922336/
https://www.ncbi.nlm.nih.gov/pubmed/24502320
http://dx.doi.org/10.1186/1756-0500-7-82
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author Zhao, Zhanqi
Pulletz, Sven
Frerichs, Inéz
Müller-Lisse, Ullrich
Möller, Knut
author_facet Zhao, Zhanqi
Pulletz, Sven
Frerichs, Inéz
Müller-Lisse, Ullrich
Möller, Knut
author_sort Zhao, Zhanqi
collection PubMed
description BACKGROUND: The electrical impedance tomography (EIT)-based global inhomogeneity (GI) index was introduced to quantify tidal volume distribution within the lung. Up to now, the GI index was evaluated for plausibility but the analysis of how it is influenced by various physiological factors is still missing. The aim of our study was to evaluate the influence of proportion of open lung regions measured by EIT on the GI index. METHODS: A constant low-flow inflation maneuver was performed in 18 acute respiratory distress syndrome (ARDS) patients (58 ± 14 years, mean age ± SD) and 8 lung-healthy patients (41 ± 12 years) under controlled mechanical ventilation. EIT raw data were acquired at 25 scans/s and reconstructed offline. Recruited lung regions were identified as those image pixels of the lung regions within the EIT scans where local impedance amplitudes exceeded 10% of the maximum amplitude during the maneuver. A series of GI indices was calculated during mechanical lung inflation, based on the differential images obtained between different time points. Respiratory system elastance (E(rs)) values were calculated at 10 lung volume levels during low-flow maneuver. RESULTS: The GI index decreased during low-flow inflation, while the percentage of open lung regions increased. The values correlated highly in both ARDS (r(2) = 0.88 ± 0.08, p < 0.01) and lung-healthy patients (r(2) = 0.92 ± 0.05, p < 0.01). E(rs) and GI index were also significantly correlated in 16 out of 18 ARDS (r(2) = 0.84 ± 0.13, p < 0.01) and in 6 out of 8 lung-healthy patients (r(2) = 0.84 ± 0.07, p < 0.01). Significant differences were found in GI values between two groups (0.52 ± 0.21 for ARDS and 0.41 ± 0.04 for lung-healthy patients, p < 0.05) as well in E(rs) values (0.017 ± 0.008 cmH(2)O/ml for ARDS and 0.009 ± 0.001 cmH(2)O/ml for lung-healthy patients, p < 0.01). CONCLUSIONS: We conclude that the GI index is a reliable measure of ventilation heterogeneity highly correlated with lung recruitability measured with EIT. The GI index may prove to be a useful EIT-based index to guide ventilation therapy.
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spelling pubmed-39223362014-02-26 The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome Zhao, Zhanqi Pulletz, Sven Frerichs, Inéz Müller-Lisse, Ullrich Möller, Knut BMC Res Notes Research Article BACKGROUND: The electrical impedance tomography (EIT)-based global inhomogeneity (GI) index was introduced to quantify tidal volume distribution within the lung. Up to now, the GI index was evaluated for plausibility but the analysis of how it is influenced by various physiological factors is still missing. The aim of our study was to evaluate the influence of proportion of open lung regions measured by EIT on the GI index. METHODS: A constant low-flow inflation maneuver was performed in 18 acute respiratory distress syndrome (ARDS) patients (58 ± 14 years, mean age ± SD) and 8 lung-healthy patients (41 ± 12 years) under controlled mechanical ventilation. EIT raw data were acquired at 25 scans/s and reconstructed offline. Recruited lung regions were identified as those image pixels of the lung regions within the EIT scans where local impedance amplitudes exceeded 10% of the maximum amplitude during the maneuver. A series of GI indices was calculated during mechanical lung inflation, based on the differential images obtained between different time points. Respiratory system elastance (E(rs)) values were calculated at 10 lung volume levels during low-flow maneuver. RESULTS: The GI index decreased during low-flow inflation, while the percentage of open lung regions increased. The values correlated highly in both ARDS (r(2) = 0.88 ± 0.08, p < 0.01) and lung-healthy patients (r(2) = 0.92 ± 0.05, p < 0.01). E(rs) and GI index were also significantly correlated in 16 out of 18 ARDS (r(2) = 0.84 ± 0.13, p < 0.01) and in 6 out of 8 lung-healthy patients (r(2) = 0.84 ± 0.07, p < 0.01). Significant differences were found in GI values between two groups (0.52 ± 0.21 for ARDS and 0.41 ± 0.04 for lung-healthy patients, p < 0.05) as well in E(rs) values (0.017 ± 0.008 cmH(2)O/ml for ARDS and 0.009 ± 0.001 cmH(2)O/ml for lung-healthy patients, p < 0.01). CONCLUSIONS: We conclude that the GI index is a reliable measure of ventilation heterogeneity highly correlated with lung recruitability measured with EIT. The GI index may prove to be a useful EIT-based index to guide ventilation therapy. BioMed Central 2014-02-06 /pmc/articles/PMC3922336/ /pubmed/24502320 http://dx.doi.org/10.1186/1756-0500-7-82 Text en Copyright © 2014 Zhao et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.
spellingShingle Research Article
Zhao, Zhanqi
Pulletz, Sven
Frerichs, Inéz
Müller-Lisse, Ullrich
Möller, Knut
The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title_full The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title_fullStr The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title_full_unstemmed The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title_short The EIT-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
title_sort eit-based global inhomogeneity index is highly correlated with regional lung opening in patients with acute respiratory distress syndrome
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3922336/
https://www.ncbi.nlm.nih.gov/pubmed/24502320
http://dx.doi.org/10.1186/1756-0500-7-82
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