Electrical impedance tomography: a method for monitoring regional lung aeration and tidal volume distribution?

Electrical impedance tomography (EIT), a noninvasive and radiation-free medical imaging technique, has been used for continuous real-time regional lung aeration. However, adhesive electrodes could cause discomfort and increase the risk of skin injury during prolonged measurement. Additionally, the conductive gel between the electrodes and skin could evaporate in long-term usage and deteriorate the signal quality. To address these issues, in this work, textile electrodes integrated with a clothing belt are proposed to achieve EIT lung imaging along with a custom portable EIT system. The simulation and experimental results have verified the validity of the proposed portable EIT system. Furthermore, the imaging results of using the proposed textile electrodes were compared with commercial electrocardiogram electrodes to evaluate their performance.

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Dynamics of regional lung aeration determined by electrical impedance tomography in patients with acute respiratory distress syndrome

Multidisciplinary Respiratory Medicine ◽

10.4081/mrm.2012.631 ◽

2012 ◽

Vol 7 ◽

Author(s):

Sven Pulletz ◽

Matthias Kott ◽

Gunnar Elke ◽

Dirk Schädler ◽

Barbara Vogt ◽

...

Keyword(s):

Acute Respiratory Distress Syndrome ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Distress Syndrome ◽

Impedance Tomography ◽

Time Constants ◽

Lung Aeration ◽

Regional Lung

Background: Lung tissue of patients with acute respiratory distress syndrome (ARDS) is heterogeneously damaged and prone to develop atelectasis. During inflation, atelectatic regions may exhibit alveolar recruitment accompanied by prolonged filling with air in contrast to regions with already open alveoli with a fast increase in regional aeration. During deflation, derecruitment of injured regions is possible with ongoing loss in regional aeration. The aim of our study was to assess the dynamics of regional lung aeration in mechanically ventilated patients with ARDS and its dependency on positive end-expiratory pressure (PEEP) using electrical impedance tomography (EIT). Methods: Twelve lung healthy and twenty ARDS patients were examined by EIT during sustained step increases in airway pressure from 0, 8 and 15 cm H2O to 35 cm H2O and during subsequent step decrease to the corresponding PEEP. Regional EIT waveforms in the ventral and dorsal lung regions were fitted to bi-exponential equations. Regional fast and slow respiratory time constants and the sizes of the fast and slow compartments were subsequently calculated. Results: ARDS patients exhibited significantly lower fast and slow time constants than the lung healthy patients in ventral and dorsal regions. The time constants were significantly affected by PEEP and differed between the regions. The size of the fast compartment was significantly lower in ARDS patients than in patients with healthy lung under all studied conditions. Conclusion: These results show that regional lung mechanics can be assessed by EIT. They reflect the lower respiratory system compliance of injured lungs and imply more pronounced regional recruitment and derecruitment in ARDS patients.

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Effects of PEEP on the relationship between tidal volume and total impedance change measured via electrical impedance tomography (EIT)

Journal of Clinical Monitoring and Computing ◽

10.1007/s10877-021-00651-x ◽

2021 ◽

Author(s):

O. Brabant ◽

B. Crivellari ◽

G. Hosgood ◽

A. Raisis ◽

A. D. Waldmann ◽

...

Keyword(s):

Tidal Volume ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Impedance Change ◽

Impedance Tomography ◽

The Relationship ◽

Total Impedance

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EXPRESS: Rapid dynamic bedside assessment of pulmonary perfusion defect by electrical impedance tomography in a patient with acute massive pulmonary embolism

Pulmonary Circulation ◽

10.1177/2045894020984043 ◽

2020 ◽

pp. 204589402098404

Author(s):

Siyi Yuan ◽

Huaiwu He ◽

Yun Long ◽

Yi Chi ◽

InÃ©z Frerichs ◽

...

Keyword(s):

Pulmonary Embolism ◽

Electrical Impedance Tomography ◽

Perfusion Defect ◽

Electrical Impedance ◽

Massive Pulmonary Embolism ◽

Lung Perfusion ◽

Regional Perfusion ◽

Pulmonary Perfusion ◽

Impedance Tomography ◽

Regional Lung

Background: Several animal studies have shown that regional lung perfusion could be effectively estimated by the hypertonic saline contrast electrical impedance tomography (EIT) method. Here, we reported an application of this method to dynamically assess regional pulmonary perfusion defect in a patient with acute massive pulmonary embolism. Case presentation: A 68-year-old man experienced sudden dyspnea and cardiac arrest during out-of-bed physical activity on the first day after partial mediastinal tumor resection. Acute pulmonary embolism (PE) was suspected due to acute enlargement of right heart and fixed inferior venous cava measured with bedside ultrasound. The computed tomography pulmonary angiography further confirmed large embolism in both left and right main pulmonary arteries and branches. The regional time impedance curves, which were obtained by a bolus of 10ml 10% NaCl through the central venous catheter, were then analyzed to quantitatively assess regional perfusion. Normal ventilation distribution with massive defects in regional perfusion in both lungs was observed, leading to a ventilation-perfusion mismatch and low oxygenation index (PaO2/FiO2=86 mmHg) at the first day of PE. The anticoagulation was performed with heparin, and the patientâs condition (such as shock, dyspnea, hypoxemia etc.), regional lung perfusion defect and ventilation-perfusion mismatch continuously improved in the following days. Conclusions: This case implies that EIT might have the potential to assess and monitor regional perfusion for rapid diagnosis of fatal PE in clinical practice.

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