Combined effects of body positioning and noninvasive ventilation on the regional distribution of pulmonary ventilation evaluated by electrical impedance tomography in the young and the elderly

2019 ◽  
Author(s):  
Liegina Silveira Marinho ◽  
Andrea Nobrega Cirino Nogueira Da Nobrega Cirino Nogueira ◽  
Juliana Arcanjo Lino ◽  
Gabriela De Carvalho Gomes Frota ◽  
Renata Dos Santos Vasconcelos ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Noninvasive Ventilation ◽  
Electrical Impedance ◽  
Pulmonary Ventilation ◽  
Regional Distribution ◽  
The Elderly ◽  
Combined Effects ◽  
Impedance Tomography ◽  
Body Positioning

scholarly journals Evaluation of Regional Pulmonary Ventilation in Spontaneously Breathing Patients with Idiopathic Pulmonary Fibrosis (IPF) Employing Electrical Impedance Tomography (EIT): A Pilot Study from the European IPF Registry (eurIPFreg)

2021 ◽  
Vol 10 (2) ◽  
pp. 192
Author(s):  
Ekaterina Krauss ◽  
Daniel van der Beck ◽  
Isabel Schmalz ◽  
Jochen Wilhelm ◽  
Silke Tello ◽  
...  
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Electrical Impedance Tomography ◽  
Spontaneous Breathing ◽  
Electrical Impedance ◽  
Statistical Significance ◽  
Pulmonary Ventilation ◽  
Healthy Controls ◽  
Impedance Tomography ◽  
Spontaneously Breathing

Objectives: In idiopathic pulmonary fibrosis (IPF), alterations in the pulmonary surfactant system result in an increased alveolar surface tension and favor repetitive alveolar collapse. This study aimed to assess the usefulness of electrical impedance tomography (EIT) in characterization of regional ventilation in IPF. Materials and methods: We investigated 17 patients with IPF and 15 healthy controls from the University of Giessen and Marburg Lung Center (UGMLC), Germany, for differences in the following EIT parameters: distribution of ventilation (TID), global inhomogeneity index (GI), regional impedance differences through the delta of end-expiratory lung impedance (dEELI), differences in surface of ventilated area (SURF), as well as center of ventilation (CG) and intratidal gas distribution (ITV). These parameters were assessed under spontaneous breathing and following a predefined escalation protocol of the positive end-expiratory pressure (PEEP), applied through a face mask by an intensive care respirator (EVITA, Draeger, Germany). Results: Individual slopes of dEELI over the PEEP increment protocol were found to be highly significantly increased in both groups (p < 0.001) but were not found to be significantly different between groups. Similarly, dTID slopes were increasing in response to PEEP, but this did not reach statistical significance within or between groups. Individual breathing patterns were very heterogeneous. There were no relevant differences of SURF, GI or CGVD over the PEEP escalation range. A correlation of dEELI to FVC, BMI, age, or weight did not forward significant results. Conclusions: In this study, we did see a significant increase in dEELI and a non-significant increase in dTID in IPF patients as well as in healthy controls in response to an increase of PEEP under spontaneous breathing. We propose the combined measurements of EIT and lung function to assess regional lung ventilation in spontaneously breathing subjects.

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.

scholarly journals Redistribution of pulmonary ventilation after lung surgery detected with electrical impedance tomography

2019 ◽  
Vol 64 (4) ◽  
pp. 517-525 ◽  
Author(s):  
Martin Lehmann ◽  
Beatrice Oehler ◽  
Jonas Zuber ◽  
Uwe Malzahn ◽  
Thorsten Walles ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Pulmonary Ventilation ◽  
Lung Surgery ◽  
Impedance Tomography

scholarly journals Gravitational distribution of regional opening and closing pressures, hysteresis and atelectrauma in ARDS evaluated by electrical impedance tomography

Critical Care ◽  
2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Gaetano Scaramuzzo ◽  
Elena Spinelli ◽  
Savino Spadaro ◽  
Alessandro Santini ◽  
Donatella Tortolani ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Regional Distribution ◽  
Low Flow ◽  
Dependent Lung ◽  
Impedance Tomography ◽  
Lung Physiology ◽  
Volume Curve ◽  
Opening And Closing ◽  
Closing Pressure

Abstract Background The physiological behavior of lungs affected by the acute respiratory distress syndrome (ARDS) differs between inspiration and expiration and presents heterogeneous gravity-dependent distribution. This phenomenon, highlighted by the different distribution of opening/closing pressure and by the hysteresis of the pressure–volume curve, can be studied by CT scan, but the technique expose the patient to radiations, cannot track changes during time and is not feasible at the bedside. Electrical impedance tomography (EIT) could help in assessing at the bedside regional inspiratory and expiratory mechanical properties. We evaluated regional opening/closing pressures, hysteresis and atelectrauma during inspiratory and expiratory low-flow pressure–volume curves in ARDS using electrical impedance tomography. Methods Pixel-level inspiratory and expiratory PV curves (PVpixel) between 5 and 40 cmH2O were constructed integrating EIT images and airway opening pressure signal from 8 ARDS patients. The lower inflection point in the inspiratory and expiratory PVpixel were used to find opening (OPpixel) and closing (CPpixel) pressures. A novel atelectrauma index (AtI) was calculated as the percentage of pixels opening during the inspiratory and closing during the expiratory PV curves. The maximal hysteresis (HysMax) was calculated as the maximal difference between normalized expiratory and inspiratory PV curves. Analyses were conducted in the global, dependent and non-dependent lung regions. Results Gaussian distribution was confirmed for both global OPpixel (r2 = 0.90) and global CPpixel (r2 = 0.94). The two distributions were significantly different with higher values for OPpixel (p < 0.0001). Regional OPpixel and CPpixel distributions were Gaussian, and in the dependent lung regions, both were significantly higher than in the non-dependent ones (p < 0.001). Both AtI and the HysMax were significantly higher in the dependent regions compared to the non-dependent ones (p < 0.05 for both). Conclusions Gravity impacts the regional distribution of opening and closing pressure, hysteresis and atelectrauma, with higher values in the dorsal lung. Regional differences between inspiratory and expiratory lung physiology are detectable at the bedside using EIT and could allow in-depth characterization of ARDS phenotypes and guide personalized ventilation settings. Graphic abstract

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.

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