ARDS: Hohe Aussagekraft der elektrischen Impedanztomographie für Diagnostik und Therapie

2021 ◽  
pp. 1-3
Author(s):  
Johannes Knoch
Keyword(s):  
Electrical Impedance ◽  
Prospective Observational Study ◽  
Distress Syndrome ◽  
Regional Distribution ◽  
Impedance Tomography ◽  
Mechanically Ventilated ◽  
Risk Of Death ◽  
Diagnostik Und Therapie ◽  
Ventilation Induced Lung Injury ◽  
Ventilation And Perfusion

<b>Background:</b> In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO<sub>2</sub>/FiO<sub>2</sub> and compliance. <b>Methods:</b> Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. <b>Results:</b> Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32 [27–47]% vs. 21 [17–27]%, <i>p</i> &#x3c; 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07–1.39, <i>p</i> = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79–0.97, <i>p</i> &#x3c; 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27–38]% vs. 18 [13–21]%, <i>p</i> &#x3c; 0.001), while the opposite was true for perfusion (28 [22–38]% vs. 36 [32–44]%, <i>p</i> &#x3c; 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (<i>r</i> = − 0.486, <i>p</i> &#x3c; 0.001) and with lower PaO<sub>2</sub>/FiO<sub>2</sub> ratio (<i>r</i> = -0.293, <i>p</i> = 0.039). <b>Conclusions:</b> EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.

scholarly journals Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Elena Spinelli ◽  
Michael Kircher ◽  
Birgit Stender ◽  
Irene Ottaviani ◽  
Maria C. Basile ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Prospective Observational Study ◽  
Distress Syndrome ◽  
Regional Distribution ◽  
Impedance Tomography ◽  
Mechanically Ventilated ◽  
Risk Of Death ◽  
Ventilation Induced Lung Injury ◽  
Ventilation And Perfusion

Abstract Background In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. Methods Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. Results Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27–47]% vs. 21[17–27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07–1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79–0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27–38]% vs. 18 [13–21]%, p < 0.001), while the opposite was true for perfusion (28 [22–38]% vs. 36 [32–44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r =  − 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r =  − 0.293, p = 0.039). Conclusions EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.

scholarly journals Helping students to understand physiological aspects of regional distribution of ventilation in humans: a experience from the electrical impedance tomography

2018 ◽  
Vol 42 (4) ◽  
pp. 655-660
Author(s):  
Marcelo Alcantara Holanda ◽  
Nathalia Parente de Sousa ◽  
Luana Torres Melo ◽  
Liégina Silveira Marinho ◽  
Helder Veras Ribeiro-Filho ◽  
...  
Keyword(s):  
Medical Students ◽  
Electrical Impedance ◽  
Respiratory Mechanics ◽  
Pulmonary Ventilation ◽  
Regional Distribution ◽  
Lung Ventilation ◽  
Respiratory Physiology ◽  
Impedance Tomography ◽  
Lateral Decubitus ◽  
Basic Concepts

Undergraduate biomedical students often have difficulties in understanding basic concepts of respiratory physiology, particularly respiratory mechanics. In this study, we report the use of electrical impedance tomography (EIT) to improve and consolidate the knowledge about physiological aspects of normal regional distribution of ventilation in humans. Initially, we assessed the previous knowledge of a group of medical students ( n = 39) about regional differences in lung ventilation. Thereafter, we recorded the regional distribution of ventilation through surface electrodes on a healthy volunteer adopting four different decubitus positions: supine, prone, and right and left lateral. The recordings clearly showed greater pulmonary ventilation in the dependent lung, mainly in the lateral decubitus. Considering the differences in pulmonary ventilation between right and left lateral decubitus, only 33% of students were able to notice it correctly beforehand. This percentage increased to 84 and 100%, respectively ( P < 0.01), after the results of the ventilation measurements obtained with EIT were examined and discussed. A self-assessment questionnaire showed that students considered the practical activity as an important tool to assist in the understanding of the basic concepts of respiratory mechanics. Experimental demonstration of the physiological variations of regional lung ventilation in volunteers by using EIT is feasible, effective, and stimulating for undergraduate medical students. Therefore, this practical activity may help faculty and students to overcome the challenges in the field of respiratory physiology learning.

What hinders pulmonary gas exchange and changes distribution of ventilation in immobilized white rhinoceroses (Ceratotherium simum) in lateral recumbency?

2020 ◽  
Vol 129 (5) ◽  
pp. 1140-1149
Author(s):  
Martina Mosing ◽  
Andreas D. Waldmann ◽  
Muriel Sacks ◽  
Peter Buss ◽  
Jordyn M. Boesch ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Breath Holding ◽  
Dependent Lung ◽  
Regional Ventilation ◽  
Impedance Tomography ◽  
Ventilation And Perfusion ◽  
Lateral Recumbency ◽  
Nondependent Lung

Electrical impedance tomography measurements of regional ventilation and perfusion applied to etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional shift of the measured ventilation and perfusion toward the nondependent lung. The dependent lung was minimally ventilated and perfused, but still aerated. Perfusion was found primarily around the hilum of the nondependent lung. These shifts can explain the gas exchange impairments found in this study. Breath holding can redistribute ventilation.

Sign in / Sign up

Export Citation Format

Share Document