Comparison of electrical impedance tomography, blood gas analysis, and respiratory mechanics for positive end-expiratory pressure titration

IF 8.8 1区 医学 Q1 CRITICAL CARE MEDICINE
Han Chen, Takeshi Yoshida, Jian-Xin Zhou
{"title":"Comparison of electrical impedance tomography, blood gas analysis, and respiratory mechanics for positive end-expiratory pressure titration","authors":"Han Chen, Takeshi Yoshida, Jian-Xin Zhou","doi":"10.1186/s13054-024-05137-1","DOIUrl":null,"url":null,"abstract":"<p><b>To the Editor</b></p><p>Electrical impedance tomography (EIT) is increasingly utilized for tailoring positive end-expiratory pressure (PEEP). By non-invasively assessing lung collapse and over-distention [1], EIT helps adjust PEEP to minimize both conditions, assuming they are equally harmful. The EIT-guided PEEP selection approach may potentially provide more lung protection by reducing mechanical power [2].</p><p>Although the balance between over-distension and collapse may help individualize PEEP titration, the requirement for specialized EIT equipment limits its widespread application. Furthermore, EIT focuses on morphology without considering PEEP's impact on hemodynamics and ventilation-perfusion matching. Alternatively, PEEP can be titrated by calculating intrapulmonary shunt (Qs/Qt) and dead space (Vd/Vt) using blood gases [3]. High alveolar pressure can cause both lung over-distension (high stress and strain) and pulmonary capillary collapse and subsequently impaired CO<sub>2</sub> elimination (namely functional over-distension). However, whether the calculated Vd/Vt and Qs/Qt are consistent with EIT-derived over-distension and collapse is unclear. In this pilot study, we attempted to compare these PEEP selection approaches.</p><p>The experiment protocol was approved by the Animal Care Committee of Fujian Provincial Hospital. The animals were treated in compliance with the hospital's guidelines for the care and utilization of laboratory animals.</p><h3>Preparation and measurements</h3><p>Eight male Bama miniatured pigs (weight 40.1 to 58.0 kg) were anesthetized with 10 mg·kg<sup>–1</sup>·h<sup>–1</sup> pentobarbital. Rocuronium bromide boluses of 0.5 mg·kg<sup>–1</sup> were administered as needed to suppress spontaneous breathing. After tracheotomy, mechanical ventilation was initiated. A catheter in the right carotid artery enabled blood pressure monitoring and gas sampling. A Swan-Ganz catheter, inserted via the internal jugular vein, facilitated mixed venous blood sampling and hemodynamic measurements. Mixed expired CO<sub>2</sub> (PeCO<sub>2</sub>) was measured via a mainstream PeCO<sub>2</sub> module. Vital signs and cardiac output (via thermodilution) were monitored. Collapse and over-distension were determined using EIT (PulmoVista 500, Dräger, Germany) at the 4th–5th intercostal space, with thresholds previously reported [1].</p><h3>Experiment protocol</h3><p>Lung injury was induced using a 'two-hits' model: surfactant depletion and injurious ventilation [4]. Saline lung lavage (30 ml·kg-1) was repeated until PaO<sub>2</sub>/FiO<sub>2</sub> &lt; 100 mmHg for 10 min at PEEP 5 cmH<sub>2</sub>O, followed by injurious ventilation for 60 min, with driving pressure/PEEP adjusted every 15 min [4].</p><p>After lung recruitment, a decremental PEEP trial (20 to 4 cmH<sub>2</sub>O, 2 cmH<sub>2</sub>O steps) was conducted. Static compliance, cardiac output, and blood gases were measured at each PEEP level. EIT data were continuously recorded for offline analysis. Pigs were euthanized post-experiment with pentobarbital overdose. Qs/Qt and Vd/Vt were calculated using established formulas (5). 'Optimal' PEEPs were determined by three methods: minimal sum of Vd/Vt and Qs/Qt, maximal compliance, and minimal sum of EIT-measured over-distension and collapse. The lower PEEP was selected in case of a tie.</p><p>As PEEP decreased, collapse and Qs/Qt increased in parallel. PaO<sub>2</sub> exhibited a non-linear relationship with PEEP changes and did not correlate strongly with collapse (Fig. 1A). As PEEP was reduced, over-distension decreased, while Vd/Vt increased (Fig. 1B). Lung compliance peaked at PEEP of 16 cmH<sub>2</sub>O, while the sum of collapse and over-distension was minimized at PEEP of 18 cmH<sub>2</sub>O (Fig. 1C). Blood pressure and cardiac output increased following the decrement of PEEP (Fig. 1D). At the individual level, 'Optimal' PEEP values varied among the three approaches. The EIT-guided approach and Vd/Vt + Qs/Qt method based on blood gas analysis showed discrepancies in PEEP values for all animals. However, when comparing the EIT-guided approach with the best compliance method, two animals exhibited identical PEEP values, while differences remained in others (Fig. 1E). End-of-experiment lung pathology showed no differences among animals (Fig. 1F).</p><figure><figcaption><b data-test=\"figure-caption-text\">Fig. 1</b></figcaption><picture><img alt=\"figure 1\" aria-describedby=\"Fig1\" height=\"537\" loading=\"lazy\" src=\"//media.springernature.com/lw685/springer-static/image/art%3A10.1186%2Fs13054-024-05137-1/MediaObjects/13054_2024_5137_Fig1_HTML.png\" width=\"685\"/></picture><p>Panel A: Showing the change of intrapulmonary shunt (Qs/Qt), PaO<sub>2</sub>, and collapse (CL) in response to the decrement of positive end-expiratory pressure (PEEP). Intrapulmonary shunt (Qs/Qt) and collapse (CL) were displayed on the left y-axis, while PaO<sub>2</sub> was displayed on the right y-axis. The trend indicates an increase in both Qs/Qt and CL with the decrement of PEEP, and the trend correlated well between Qs/Qt and CL. PaO<sub>2</sub> demonstrated a biphasic response, initially ascending, followed by a subsequent decline. Panel B: Showing the change of arterial CO<sub>2</sub> partial pressure (PaCO<sub>2</sub>), mixed expired CO<sub>2</sub> partial pressure (PeCO<sub>2</sub>), dead space (Vd/Vt), over-distension (OD) in response to the decrement of PEEP. Vd/Vt and OD were displayed on the left y-axis, while PaCO<sub>2</sub> and PeCO<sub>2</sub> were displayed on the right y-axis. As PEEP decreased, the gap between PaCO<sub>2</sub> and PeCO<sub>2</sub> increased, resulting in an increasing Vd/Vt. In contrast, OD decreased following the decrement of PEEP. Panel C: CL and OD were plotted on the same graph, both displayed on the left y-axis, to illustrate the trend of their sum, which exhibited a U-shaped trend. Additionally, Qs/Qt and Vd/Vt were also plotted on the left y-axis. The right y-axis shows the changes in compliance (Crs), which demonstrated an inverse U-shaped trend. Panel D: Cardiac output (CO) and mean arterial pressure (MAP) gradually increased as PEEP decreased. Panel E: 'Optimal' PEEP selected by EIT (minimal sum of CL and OD, <i>circle</i>), minimal Vd/Vt + Qs/Qt (<i>square</i>), and the best Crs (<i>diamond</i>). The selected PEEP levels by the three approaches exhibited notable discrepancies. Panel F: Showing the lung injury scores at the end of the experiment for each animal. For each animal, six non-overlapping fields were collected and averaged. Briefly, hematoxylin and eosin–stained sections were analyzed for neutrophil infiltration, airway epithelial cell damage, interstitial edema, hyaline membrane formation, hemorrhage, and the total lung injury score as the sum of these criteria. Each criterion was scored on a scale of 0–4, where 0 = normal, 1 = minimal change, 2 = mild change, 3 = moderate change, and 4 = severe change. There were no significant differences in lung injury scores among the animals (p = 0.378)</p><span>Full size image</span><svg aria-hidden=\"true\" focusable=\"false\" height=\"16\" role=\"img\" width=\"16\"><use xlink:href=\"#icon-eds-i-chevron-right-small\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"></use></svg></figure><p>In this pilot experiment, we compared blood-gas-based PEEP titration with EIT to balance over-distension and collapse. Qs/Qt effectively evaluated collapsed tissue without EIT. In contrast, dead space was not effective in detecting over-distension. A notable discrepancy existed between PEEP titration approaches.</p><p>Pulmonary gas exchange depends not only on ventilation but also on matching the blood flow. High PEEP affects hemodynamics, lung perfusion, and ventilation-perfusion matching. Blood-gas-analysis-derived over-distension results from both \"true\" and \"functional\" over-distension (5). We found that Qs/Qt + Vd/Vt derived PEEP was occasionally higher than EIT-derived PEEP, contrary to expectations. While individual animals showed variable optimal PEEP values across methods, averaged data indicated a consistent range of 16–18 cmH₂O. This highlights individual heterogeneity, suggesting that averaged data may mask crucial individual differences. These findings underscore the importance of considering multiple parameters and personalizing PEEP settings.</p><p>This study has some limitations. It's a small, non-randomized pilot study. Second, we used the Enghoff formula to calculate dead space, which includes the shunt effect. PEEP can simultaneously affect true dead space and shunt oppositely, while we assumed minimal shunt effect at high PEEP. Additionally, we didn't compare injury degree (histological, biomarkers) from different PEEP approaches.</p><p>In conclusion, morphology-based and blood gas-based approaches yielded different optimal PEEP levels. The impact of these varying approaches on lung injury warrants further study.</p><p>No datasets were generated or analysed during the current study.</p><dl><dt style=\"min-width:50px;\"><dfn>CL:</dfn></dt><dd>\n<p>Collapse</p>\n</dd><dt style=\"min-width:50px;\"><dfn>CO:</dfn></dt><dd>\n<p>Cardiac output</p>\n</dd><dt style=\"min-width:50px;\"><dfn>CO<sub>2</sub> :</dfn></dt><dd>\n<p>Carbon dioxide</p>\n</dd><dt style=\"min-width:50px;\"><dfn>Crs:</dfn></dt><dd>\n<p>Compliance of respiratory system</p>\n</dd><dt style=\"min-width:50px;\"><dfn>EIT:</dfn></dt><dd>\n<p>Electrical impedance tomography</p>\n</dd><dt style=\"min-width:50px;\"><dfn>FiO<sub>2</sub> :</dfn></dt><dd>\n<p>Fraction of inspired oxygen</p>\n</dd><dt style=\"min-width:50px;\"><dfn>MAP:</dfn></dt><dd>\n<p>Mean arterial pressure</p>\n</dd><dt style=\"min-width:50px;\"><dfn>OD:</dfn></dt><dd>\n<p>Over-distension</p>\n</dd><dt style=\"min-width:50px;\"><dfn>PaCO<sub>2</sub> :</dfn></dt><dd>\n<p>Arterial CO<sub>2</sub> partial pressure</p>\n</dd><dt style=\"min-width:50px;\"><dfn>PaO<sub>2</sub> :</dfn></dt><dd>\n<p>Partial pressure of arterial oxygen</p>\n</dd><dt style=\"min-width:50px;\"><dfn>PeCO<sub>2</sub> :</dfn></dt><dd>\n<p>Mixed expired CO<sub>2</sub> partial pressure</p>\n</dd><dt style=\"min-width:50px;\"><dfn>PEEP:</dfn></dt><dd>\n<p>Positive end-expiratory pressure</p>\n</dd><dt style=\"min-width:50px;\"><dfn>Qs/Qt:</dfn></dt><dd>\n<p>Intrapulmonary shunt</p>\n</dd><dt style=\"min-width:50px;\"><dfn>Vd/Vt:</dfn></dt><dd>\n<p>Dead space</p>\n</dd></dl><ol data-track-component=\"outbound reference\" data-track-context=\"references section\"><li data-counter=\"1.\"><p>Costa EL, Borges JB, Melo A, Suarez-Sipmann F, Toufen C Jr, Bohm SH, et al. Bedside estimation of recruitable alveolar collapse and hyperdistension by electrical impedance tomography. Intensive Care Med. 2009;35:1132–7.</p><p>Article PubMed Google Scholar </p></li><li data-counter=\"2.\"><p>Jimenez JV, Munroe E, Weirauch AJ, Fiorino K, Culter CA, Nelson K, et al. Electric impedance tomography-guided PEEP titration reduces mechanical power in ARDS: a randomized crossover pilot trial. Crit Care. 2023;27:21.</p><p>Article PubMed PubMed Central Google Scholar </p></li><li data-counter=\"3.\"><p>Tusman G, Gogniat E, Madorno M, Otero P, Dianti J, Ceballos IF, et al. Effect of PEEP on dead space in an experimental model of ARDS. Respir Care. 2020;65:11–20.</p><p>Article PubMed Google Scholar </p></li><li data-counter=\"4.\"><p>Yoshida T, Engelberts D, Chen H, Li X, Katira BH, Otulakowski G, et al. Prone position minimizes the exacerbation of effort-dependent lung injury: exploring the mechanism in pigs and evaluating injury in rabbits. Anesthesiology. 2022;136:779–91.</p><p>Article CAS PubMed Google Scholar </p></li><li data-counter=\"5.\"><p>Suárez-Sipmann F, Villar J, Ferrando C, Sánchez-Giralt JA, Tusman G. Monitoring expired CO(2) kinetics to individualize lung-protective ventilation in patients with the acute respiratory distress syndrome. Front Physiol. 2021;12:785014.</p><p>Article PubMed PubMed Central Google Scholar </p></li></ol><p>Download references<svg aria-hidden=\"true\" focusable=\"false\" height=\"16\" role=\"img\" width=\"16\"><use xlink:href=\"#icon-eds-i-download-medium\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"></use></svg></p><p>None.</p><p>HC is supported by the Youth Top Talent Project of Fujian Provincial Foal Eagle Program. The funding bodies had no role in the study design, data collection, analysis, interpretation, or manuscript writing.</p><h3>Authors and Affiliations</h3><ol><li><p>Department of Critical Care Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital Affiliated to Fuzhou University, Fujian Provincial Center for Critical Care Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Dongjie 134, Gulou District, Fuzhou, Fujian, China</p><p>Han Chen</p></li><li><p>Department of Anesthesiology and Intensive Care Medicine, Osaka University Graduate School of Medicine, Suita, Japan</p><p>Takeshi Yoshida</p></li><li><p>Beijing Shijitan Hospital, Capital Medical University, Beijing, China</p><p>Jian-Xin Zhou</p></li></ol><span>Authors</span><ol><li><span>Han Chen</span>View author publications<p>You can also search for this author in <span>PubMed<span> </span>Google Scholar</span></p></li><li><span>Takeshi Yoshida</span>View author publications<p>You can also search for this author in <span>PubMed<span> </span>Google Scholar</span></p></li><li><span>Jian-Xin Zhou</span>View author publications<p>You can also search for this author in <span>PubMed<span> </span>Google Scholar</span></p></li></ol><h3>Contributions</h3><p>HC, TY, and JXZ conceived and designed the study. HC performed the experiments and data collection. HC and TY performed data analysis and interpretation. HC prepared the initial draft of the manuscript. All authors reviewed, contributed to, and approved the article’s final version. The corresponding author ultimately submitted the manuscript for publication.</p><h3>Corresponding author</h3><p>Correspondence to Han Chen.</p><h3>Ethics approval and consent to participate</h3>\n<p>The experiment protocol was approved by the Animal Care Committee of Fujian Provincial Hospital. The animals were treated in compliance with the hospital's guidelines for the care and utilization of laboratory animals.</p>\n<h3>Consent for publication</h3>\n<p>Not applicable.</p>\n<h3>Competing interests</h3>\n<p>The authors declare no competing interests.</p><h3>Publisher's Note</h3><p>Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.</p><p><b>Open Access</b> This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.</p>\n<p>Reprints and permissions</p><img alt=\"Check for updates. 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Comparison of electrical impedance tomography, blood gas analysis, and respiratory mechanics for positive end-expiratory pressure titration. <i>Crit Care</i> <b>28</b>, 341 (2024). https://doi.org/10.1186/s13054-024-05137-1</p><p>Download citation<svg aria-hidden=\"true\" focusable=\"false\" height=\"16\" role=\"img\" width=\"16\"><use xlink:href=\"#icon-eds-i-download-medium\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"></use></svg></p><ul data-test=\"publication-history\"><li><p>Received<span>: </span><span><time datetime=\"2024-09-09\">09 September 2024</time></span></p></li><li><p>Accepted<span>: </span><span><time datetime=\"2024-10-18\">18 October 2024</time></span></p></li><li><p>Published<span>: </span><span><time datetime=\"2024-10-22\">22 October 2024</time></span></p></li><li><p>DOI</abbr><span>: </span><span>https://doi.org/10.1186/s13054-024-05137-1</span></p></li></ul><h3>Share this article</h3><p>Anyone you share the following link with will be able to read this content:</p><button data-track=\"click\" data-track-action=\"get shareable link\" data-track-external=\"\" data-track-label=\"button\" type=\"button\">Get shareable link</button><p>Sorry, a shareable link is not currently available for this article.</p><p data-track=\"click\" data-track-action=\"select share url\" data-track-label=\"button\"></p><button data-track=\"click\" data-track-action=\"copy share url\" data-track-external=\"\" data-track-label=\"button\" type=\"button\">Copy to clipboard</button><p> Provided by the Springer Nature SharedIt content-sharing initiative </p>","PeriodicalId":10811,"journal":{"name":"Critical Care","volume":null,"pages":null},"PeriodicalIF":8.8000,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Critical Care","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1186/s13054-024-05137-1","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CRITICAL CARE MEDICINE","Score":null,"Total":0}
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Abstract

To the Editor

Electrical impedance tomography (EIT) is increasingly utilized for tailoring positive end-expiratory pressure (PEEP). By non-invasively assessing lung collapse and over-distention [1], EIT helps adjust PEEP to minimize both conditions, assuming they are equally harmful. The EIT-guided PEEP selection approach may potentially provide more lung protection by reducing mechanical power [2].

Although the balance between over-distension and collapse may help individualize PEEP titration, the requirement for specialized EIT equipment limits its widespread application. Furthermore, EIT focuses on morphology without considering PEEP's impact on hemodynamics and ventilation-perfusion matching. Alternatively, PEEP can be titrated by calculating intrapulmonary shunt (Qs/Qt) and dead space (Vd/Vt) using blood gases [3]. High alveolar pressure can cause both lung over-distension (high stress and strain) and pulmonary capillary collapse and subsequently impaired CO2 elimination (namely functional over-distension). However, whether the calculated Vd/Vt and Qs/Qt are consistent with EIT-derived over-distension and collapse is unclear. In this pilot study, we attempted to compare these PEEP selection approaches.

The experiment protocol was approved by the Animal Care Committee of Fujian Provincial Hospital. The animals were treated in compliance with the hospital's guidelines for the care and utilization of laboratory animals.

Preparation and measurements

Eight male Bama miniatured pigs (weight 40.1 to 58.0 kg) were anesthetized with 10 mg·kg–1·h–1 pentobarbital. Rocuronium bromide boluses of 0.5 mg·kg–1 were administered as needed to suppress spontaneous breathing. After tracheotomy, mechanical ventilation was initiated. A catheter in the right carotid artery enabled blood pressure monitoring and gas sampling. A Swan-Ganz catheter, inserted via the internal jugular vein, facilitated mixed venous blood sampling and hemodynamic measurements. Mixed expired CO2 (PeCO2) was measured via a mainstream PeCO2 module. Vital signs and cardiac output (via thermodilution) were monitored. Collapse and over-distension were determined using EIT (PulmoVista 500, Dräger, Germany) at the 4th–5th intercostal space, with thresholds previously reported [1].

Experiment protocol

Lung injury was induced using a 'two-hits' model: surfactant depletion and injurious ventilation [4]. Saline lung lavage (30 ml·kg-1) was repeated until PaO2/FiO2 < 100 mmHg for 10 min at PEEP 5 cmH2O, followed by injurious ventilation for 60 min, with driving pressure/PEEP adjusted every 15 min [4].

After lung recruitment, a decremental PEEP trial (20 to 4 cmH2O, 2 cmH2O steps) was conducted. Static compliance, cardiac output, and blood gases were measured at each PEEP level. EIT data were continuously recorded for offline analysis. Pigs were euthanized post-experiment with pentobarbital overdose. Qs/Qt and Vd/Vt were calculated using established formulas (5). 'Optimal' PEEPs were determined by three methods: minimal sum of Vd/Vt and Qs/Qt, maximal compliance, and minimal sum of EIT-measured over-distension and collapse. The lower PEEP was selected in case of a tie.

As PEEP decreased, collapse and Qs/Qt increased in parallel. PaO2 exhibited a non-linear relationship with PEEP changes and did not correlate strongly with collapse (Fig. 1A). As PEEP was reduced, over-distension decreased, while Vd/Vt increased (Fig. 1B). Lung compliance peaked at PEEP of 16 cmH2O, while the sum of collapse and over-distension was minimized at PEEP of 18 cmH2O (Fig. 1C). Blood pressure and cardiac output increased following the decrement of PEEP (Fig. 1D). At the individual level, 'Optimal' PEEP values varied among the three approaches. The EIT-guided approach and Vd/Vt + Qs/Qt method based on blood gas analysis showed discrepancies in PEEP values for all animals. However, when comparing the EIT-guided approach with the best compliance method, two animals exhibited identical PEEP values, while differences remained in others (Fig. 1E). End-of-experiment lung pathology showed no differences among animals (Fig. 1F).

Fig. 1
Abstract Image

Panel A: Showing the change of intrapulmonary shunt (Qs/Qt), PaO2, and collapse (CL) in response to the decrement of positive end-expiratory pressure (PEEP). Intrapulmonary shunt (Qs/Qt) and collapse (CL) were displayed on the left y-axis, while PaO2 was displayed on the right y-axis. The trend indicates an increase in both Qs/Qt and CL with the decrement of PEEP, and the trend correlated well between Qs/Qt and CL. PaO2 demonstrated a biphasic response, initially ascending, followed by a subsequent decline. Panel B: Showing the change of arterial CO2 partial pressure (PaCO2), mixed expired CO2 partial pressure (PeCO2), dead space (Vd/Vt), over-distension (OD) in response to the decrement of PEEP. Vd/Vt and OD were displayed on the left y-axis, while PaCO2 and PeCO2 were displayed on the right y-axis. As PEEP decreased, the gap between PaCO2 and PeCO2 increased, resulting in an increasing Vd/Vt. In contrast, OD decreased following the decrement of PEEP. Panel C: CL and OD were plotted on the same graph, both displayed on the left y-axis, to illustrate the trend of their sum, which exhibited a U-shaped trend. Additionally, Qs/Qt and Vd/Vt were also plotted on the left y-axis. The right y-axis shows the changes in compliance (Crs), which demonstrated an inverse U-shaped trend. Panel D: Cardiac output (CO) and mean arterial pressure (MAP) gradually increased as PEEP decreased. Panel E: 'Optimal' PEEP selected by EIT (minimal sum of CL and OD, circle), minimal Vd/Vt + Qs/Qt (square), and the best Crs (diamond). The selected PEEP levels by the three approaches exhibited notable discrepancies. Panel F: Showing the lung injury scores at the end of the experiment for each animal. For each animal, six non-overlapping fields were collected and averaged. Briefly, hematoxylin and eosin–stained sections were analyzed for neutrophil infiltration, airway epithelial cell damage, interstitial edema, hyaline membrane formation, hemorrhage, and the total lung injury score as the sum of these criteria. Each criterion was scored on a scale of 0–4, where 0 = normal, 1 = minimal change, 2 = mild change, 3 = moderate change, and 4 = severe change. There were no significant differences in lung injury scores among the animals (p = 0.378)

Full size image

In this pilot experiment, we compared blood-gas-based PEEP titration with EIT to balance over-distension and collapse. Qs/Qt effectively evaluated collapsed tissue without EIT. In contrast, dead space was not effective in detecting over-distension. A notable discrepancy existed between PEEP titration approaches.

Pulmonary gas exchange depends not only on ventilation but also on matching the blood flow. High PEEP affects hemodynamics, lung perfusion, and ventilation-perfusion matching. Blood-gas-analysis-derived over-distension results from both "true" and "functional" over-distension (5). We found that Qs/Qt + Vd/Vt derived PEEP was occasionally higher than EIT-derived PEEP, contrary to expectations. While individual animals showed variable optimal PEEP values across methods, averaged data indicated a consistent range of 16–18 cmH₂O. This highlights individual heterogeneity, suggesting that averaged data may mask crucial individual differences. These findings underscore the importance of considering multiple parameters and personalizing PEEP settings.

This study has some limitations. It's a small, non-randomized pilot study. Second, we used the Enghoff formula to calculate dead space, which includes the shunt effect. PEEP can simultaneously affect true dead space and shunt oppositely, while we assumed minimal shunt effect at high PEEP. Additionally, we didn't compare injury degree (histological, biomarkers) from different PEEP approaches.

In conclusion, morphology-based and blood gas-based approaches yielded different optimal PEEP levels. The impact of these varying approaches on lung injury warrants further study.

No datasets were generated or analysed during the current study.

CL:

Collapse

CO:

Cardiac output

CO2 :

Carbon dioxide

Crs:

Compliance of respiratory system

EIT:

Electrical impedance tomography

FiO2 :

Fraction of inspired oxygen

MAP:

Mean arterial pressure

OD:

Over-distension

PaCO2 :

Arterial CO2 partial pressure

PaO2 :

Partial pressure of arterial oxygen

PeCO2 :

Mixed expired CO2 partial pressure

PEEP:

Positive end-expiratory pressure

Qs/Qt:

Intrapulmonary shunt

Vd/Vt:

Dead space

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HC is supported by the Youth Top Talent Project of Fujian Provincial Foal Eagle Program. The funding bodies had no role in the study design, data collection, analysis, interpretation, or manuscript writing.

Authors and Affiliations

  1. Department of Critical Care Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital Affiliated to Fuzhou University, Fujian Provincial Center for Critical Care Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Dongjie 134, Gulou District, Fuzhou, Fujian, China

    Han Chen

  2. Department of Anesthesiology and Intensive Care Medicine, Osaka University Graduate School of Medicine, Suita, Japan

    Takeshi Yoshida

  3. Beijing Shijitan Hospital, Capital Medical University, Beijing, China

    Jian-Xin Zhou

Authors
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Contributions

HC, TY, and JXZ conceived and designed the study. HC performed the experiments and data collection. HC and TY performed data analysis and interpretation. HC prepared the initial draft of the manuscript. All authors reviewed, contributed to, and approved the article’s final version. The corresponding author ultimately submitted the manuscript for publication.

Corresponding author

Correspondence to Han Chen.

Ethics approval and consent to participate

The experiment protocol was approved by the Animal Care Committee of Fujian Provincial Hospital. The animals were treated in compliance with the hospital's guidelines for the care and utilization of laboratory animals.

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Not applicable.

Competing interests

The authors declare no competing interests.

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Chen, H., Yoshida, T. & Zhou, JX. Comparison of electrical impedance tomography, blood gas analysis, and respiratory mechanics for positive end-expiratory pressure titration. Crit Care 28, 341 (2024). https://doi.org/10.1186/s13054-024-05137-1

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电阻抗断层扫描、血气分析和呼吸力学在呼气末正压滴定中的应用比较
致编辑电阻抗断层扫描(EIT)越来越多地被用于调整呼气末正压(PEEP)。通过无创评估肺塌陷和过度滞留[1],EIT 可帮助调整 PEEP 以尽量减少这两种情况(假设它们同样有害)。EIT 指导下的 PEEP 选择方法可能会通过减少机械力来提供更多的肺保护[2]。虽然过度张力和塌陷之间的平衡可能有助于个性化 PEEP 滴定,但对专业 EIT 设备的要求限制了其广泛应用。此外,EIT 只关注形态学,而不考虑 PEEP 对血液动力学和通气-灌注匹配的影响。另外,PEEP 也可以通过使用血气计算肺内分流(Qs/Qt)和死腔(Vd/Vt)来进行调节[3]。高肺泡压既可导致肺过度张力(高应力和应变),也可导致肺毛细血管塌陷,进而影响二氧化碳排出(即功能性过度张力)。然而,计算出的 Vd/Vt 和 Qs/Qt 是否与 EIT 导出的过度张力和塌陷一致尚不清楚。在这项试验性研究中,我们尝试比较这些 PEEP 选择方法。八头雄性巴马小型猪(体重 40.1 至 58.0 千克)用 10 毫克-千克-1-小时-1 戊巴比妥麻醉。根据需要注射 0.5 mg-kg-1 的罗库溴铵以抑制自主呼吸。气管切开后,开始机械通气。右颈动脉导管用于血压监测和气体采样。通过颈内静脉插入的 Swan-Ganz 导管有助于混合静脉血采样和血液动力学测量。混合呼出二氧化碳(PeCO2)通过主流 PeCO2 模块进行测量。对生命体征和心输出量(通过热稀释)进行监测。使用 EIT(PulmoVista 500,德国 Dräger)在第 4-5 肋间测定塌陷和过度张力,阈值先前已有报道[1]。实验方案使用 "两击 "模型诱导肺损伤:表面活性物质耗竭和损伤性通气[4]。盐水洗肺(30 ml-kg-1)重复进行,直到 PaO2/FiO2 &lt; 100 mmHg 为止,持续 10 分钟,PEEP 为 5 cmH2O,然后进行 60 分钟的损伤性通气,每 15 分钟调整一次驱动压力/PEEP[4]。在每个 PEEP 水平测量静态顺应性、心输出量和血气。连续记录 EIT 数据以进行离线分析。实验结束后,对猪实施戊巴比妥过量安乐死。Qs/Qt 和 Vd/Vt 采用既定公式计算 (5)。最佳 "PEEP 通过三种方法确定:Vd/Vt 和 Qs/Qt 的最小和、最大顺应性以及 EIT 测量的过张和塌陷的最小和。当 PEEP 下降时,塌陷度和 Qs/Qt 同步上升。PaO2 与 PEEP 的变化呈非线性关系,与塌陷的相关性不强(图 1A)。随着 PEEP 的降低,过度张力减少,而 Vd/Vt 增加(图 1B)。肺顺应性在 PEEP 为 16 cmH2O 时达到峰值,而在 PEEP 为 18 cmH2O 时,塌陷和过度张力之和最小(图 1C)。血压和心输出量随着 PEEP 的降低而增加(图 1D)。就个体而言,三种方法的 "最佳 "PEEP 值各不相同。EIT 引导法和基于血气分析的 Vd/Vt + Qs/Qt 法显示,所有动物的 PEEP 值都存在差异。然而,当将 EIT 引导法与最佳顺应性法进行比较时,有两只动物的 PEEP 值相同,而其他动物的 PEEP 值仍存在差异(图 1E)。图 1 面板 A:显示肺内分流(Qs/Qt)、PaO2 和塌陷(CL)对呼气末正压(PEEP)下降的响应变化。肺内分流(Qs/Qt)和塌陷(CL)显示在左侧 y 轴上,而 PaO2 显示在右侧 y 轴上。趋势表明,Qs/Qt 和 CL 均随 PEEP 的减小而增加,Qs/Qt 和 CL 之间的趋势相关性良好。PaO2 显示出双相反应,最初上升,随后下降。B 组:显示动脉 CO2 分压(PaCO2)、混合呼出 CO2 分压(PeCO2)、死腔(Vd/Vt)和过度张力(OD)对 PEEP 下降的响应变化。Vd/Vt 和 OD 显示在左侧 y 轴上,而 PaCO2 和 PeCO2 显示在右侧 y 轴上。
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来源期刊
Critical Care
Critical Care 医学-危重病医学
CiteScore
20.60
自引率
3.30%
发文量
348
审稿时长
1.5 months
期刊介绍: Critical Care is an esteemed international medical journal that undergoes a rigorous peer-review process to maintain its high quality standards. Its primary objective is to enhance the healthcare services offered to critically ill patients. To achieve this, the journal focuses on gathering, exchanging, disseminating, and endorsing evidence-based information that is highly relevant to intensivists. By doing so, Critical Care seeks to provide a thorough and inclusive examination of the intensive care field.
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