Related Experiment Video
Updated: Jun 12, 2026
Monitoring Lung Function with Electrical Impedance Tomography in the Intensive Care Unit
Published on: September 6, 2024
A lung area estimation method for analysis of ventilation inhomogeneity based on electrical impedance tomography
Zhanqi Zhao1, Daniel Steinmann, Danijela Müller-Zivkovic
1Department of Biomedical Engineering, Furtwangen University, Villingen-Schwenningen, Germany. zhanqi.zhao@hs-furtwangen.de
Purpose:
To evaluate a novel method for lung area estimation (LAE method) in electrical impedance tomography (EIT) images as a prerequisite of quantitative analysis of ventilation inhomogeneity.
Methods:
The LAE method mirrors the lung regions in the functional EIT (fEIT) image and subsequently subtracts the cardiac related areas. In this preliminary study, 51 mechanically ventilated patients were investigated, including 39~patients scheduled for thoracic surgery (test group); 10 patients scheduled for orthopedic surgery without pulmonary disease (control group) and 2 ICU patients undergoing chest computed tomography (CT) examination. EIT data was recorded in all groups. The results of the LAE method were compared to those obtained with the fEIT method and to CT images.
Results:
The lung area size determined with fEIT in control group is S(C,fEIT) = 361 +/- 35 (mean +/- SD) and in test group S(T,fEIT) = 299 +/- 61 (p< 0.01). The sizes estimated with the LAE method in control group S(C,LAE) = 353 +/- 27 and in test group S(T,LAE) = 353 +/- 61 (p=0.41). The result demonstrates that the novel LAE method improves the identification of lung region in EIT images, from which the analysis of ventilation distribution will benefit. The preliminary comparison with CT images exemplary indicates a closer match of the lung area shapes after the LAE than after the fEIT-based analysis.
Conclusion:
The LAE method is a robust lung area determination method, suitable for patients with healthy or seriously injured lungs.
Related Concept Videos
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement: