Comparison of two experimental ARDS models in pigs using electrical impedance tomography.

Background: Animal trials contribute to major achievements in medical science. The so-called lavage model is frequently used to evaluate ventilation strategies in acute respiratory distress syndrome (ARDS) using electrical impedance tomography (EIT). But, the lavage model itself might have systematic impacts on EIT parameters.

Reconstruction algorithm for frequency-differential EIT using absolute values.

Objective: Tissues in the body differ by their frequency-dependent conductivity. Frequency-differential electrical impedance tomography (fdEIT) is a promising technique to reconstruct the distribution of tissue inside the body by injecting current at two frequencies and measuring the resulting surface-potential.

Approach: The Gauss-Newton method is one way to map the surface measurements to a conductivity image.

Three-dimensional Pulmonary Monitoring Using Focused Electrical Impedance Measurements.

Lung pathologies such as edema, atelectasis or pneumonia are potentially life threatening conditions. Especially in critically ill and mechanically ventilated patients, an early diagnosis and treatment is crucial to prevent an Acute Respiratory Distress Syndrome [1]. Thus, continuous monitoring tool for the lung condition available at the bedside would be highly appreciated.

Lung pathologies analyzed with multi-frequency electrical impedance tomography: Pilot animal study.

In critically ill patients, correct diagnosis of lung disease is essential for successful therapy. Therefore, this study investigated whether new multi-frequency electrical impedance tomography (mfEIT) can detect, monitor and differentiate between pathologies associated with the acute respiratory distress syndrome (ARDS). For this pilot study, 12 pigs were randomized into an ARDS (bronchoalveolar lavage) group (n = 7) and a healthy control group (n = 5).

Addition of internal electrodes is beneficial for focused bioimpedance measurements in the lung.

Objective: Bioimpedance measurements such as bioimpedance spectroscopy (BIS) or electrical impedance tomography (EIT) are used in many biomedical applications. While BIS measures and analyzes the impedance in a frequency range at constant electrode positions, EIT aims to reconstruct images of the conductivity distribution from multiple measurements at different electrode positions. Our aim is to add spatial information to tetrapolar BIS measurements by using electrode positions that focus measurements on desired regions of interest.

Improved electrode positions for local impedance measurements in the lung-a simulation study.

Impedance spectroscopy can be used to analyze the dielectric properties of various materials. In the biomedical domain, it is used as bioimpedance spectroscopy (BIS) to analyze the composition of body tissue. Being a non-invasive, real-time capable technique, it is a promising modality, especially in the field of lung monitoring.