scholarly journals AN INTEGRATED PHYSIOLOGICAL MODEL OF THE LUNG MECHANICS AND GAS EXCHANGE USING ELECTRICAL IMPEDANCE TOMOGRAPHY IN THE ANALYSIS OF VENTILATION STRATEGIES IN ARDS PATIENTS

2010 ◽  
Keyword(s):  
Gas Exchange ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Physiological Model ◽  
Lung Mechanics ◽  
Impedance Tomography ◽  
Ventilation Strategies

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.

Assessing regional lung mechanics by combining electrical impedance tomography and forced oscillation technique

2018 ◽  
Vol 63 (6) ◽  
pp. 673-681 ◽  
Author(s):  
Chuong Ngo ◽  
Sarah Spagnesi ◽  
Carlos Munoz ◽  
Sylvia Lehmann ◽  
Thomas Vollmer ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Electrical Impedance Tomography ◽  
High Frequency ◽  
Electrical Impedance ◽  
Forced Oscillation ◽  
Pulmonary Function Tests ◽  
Lung Mechanics ◽  
Forced Oscillation Technique ◽  
Impedance Tomography ◽  
Regional Lung

Abstract There is a lack of noninvasive pulmonary function tests which can assess regional information of the lungs. Electrical impedance tomography (EIT) is a radiation-free, non-invasive real-time imaging that provides regional information of ventilation volume regarding the measurement of electrical impedance distribution. Forced oscillation technique (FOT) is a pulmonary function test which is based on the measurement of respiratory mechanical impedance over a frequency range. In this article, we introduce a new measurement approach by combining FOT and EIT, named the oscillatory electrical impedance tomography (oEIT). Our oEIT measurement system consists of a valve-based FOT device, an EIT device, pressure and flow sensors, and a computer fusing the data streams. Measurements were performed on five healthy volunteers at the frequencies 3, 4, 5, 6, 7, 8, 10, 15, and 20 Hz. The measurements suggest that the combination of FOT and EIT is a promising approach. High frequency responses are visible in the derivative of the global impedance index $\Delta {Z_{{\text{eit}}}}(t,{f_{{\text{os}}}}).$ The oEIT signals consist of three main components: forced oscillation, spontaneous breathing, and heart activity. The amplitude of the oscillation component decreases with increasing frequency. The band-pass filtered oEIT signal might be a new tool in regional lung function diagnostics, since local responses to high frequency perturbation could be distinguished between different lung regions.

scholarly journals Personalisation of Therapies in COVID-19 Associated Acute Respiratory Distress Syndrome, Using Electrical Impedance Tomography

2021 ◽  
Vol 7 (1) ◽  
pp. 62-66
Author(s):  
Atsuko Shono ◽  
Toru Kotani ◽  
Inéz Frerichs
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Electrical Impedance Tomography ◽  
Prone Position ◽  
Electrical Impedance ◽  
Distress Syndrome ◽  
Lung Mechanics ◽  
Ventilation Distribution ◽  
Impedance Tomography

Abstract Introduction Each patient suffering from severe coronavirus COVID-19-associated acute respiratory distress syndrome (ARDS), requiring mechanical ventilation, shows different lung mechanics and disease evolution. Therefore, lung protective strategies should be personalised for the individual patient. Case presentation A 64-year-old male patient was intubated ten days after the symptoms of COVID-19 infection presented. He was placed in the prone position for sixteen hours, resulting in a marked improvement in oxygenation. However, after being returned to the supine position, his SpO2 rapidly dropped from 98% to 91%, and electrical impedance tomography showed less ventilation at the dorsal region and a ventral shift of ventilation distribution. An incremental and decremental PEEP trial under electrical impedance tomography monitoring was carried out, confirming that the dependent lung regions were recruited with increased pressures and homogenous ventilation distribution could be provided with 14 cmH2O of PEEP. The optimal settings were reassessed next day after returning from the second session of the prone position. After four prone position-sessions in five days, oxygenation was stabilised and eventually the patient was discharged. Conclusions Patients with COVID-19 associated ARDS require individualised ventilation support depending on the stage of their disease. Daily PEEP trial monitored by electrical impedance tomography can provide important information to tailor the respiratory therapies.

scholarly journals Time-based pulmonary features from electrical impedance tomography demonstrate ventilation heterogeneity in chronic obstructive pulmonary disease

2019 ◽  
Vol 127 (5) ◽  
pp. 1441-1452 ◽  
Author(s):  
Stephen Milne ◽  
Jacqueline Huvanandana ◽  
Chinh Nguyen ◽  
Joseph M. Duncan ◽  
David G. Chapman ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Real Time ◽  
Pulmonary Disease ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Lung Mechanics ◽  
Chronic Obstructive ◽  
Impedance Tomography ◽  
Obstructive Pulmonary Disease ◽  
Ventilation Heterogeneity

Pulmonary electrical impedance tomography (EIT) is a functional imaging technique that allows real-time monitoring of ventilation distribution. Ventilation heterogeneity (VH) is a characteristic feature of chronic obstructive pulmonary disease (COPD) and has previously been quantified using features derived from tidal variations in the amplitude of the EIT signal. However, VH may be better described by time-based metrics, the measurement of which is made possible by the high temporal resolution of EIT. We aimed 1) to quantify VH using novel time-based EIT metrics and 2) to determine the physiological relevance of these metrics by exploring their relationships with complex lung mechanics measured by the forced oscillation technique (FOT). We performed FOT, spirometry, and tidal-breathing EIT measurements in 11 healthy controls and 9 volunteers with COPD. Through offline signal processing, we derived 3 features from the impedance-time ( Z- t) curve for each image pixel: 1) tE, mean expiratory time; 2) PHASE, mean time difference between pixel and global Z- t curves; and 3) AMP, mean amplitude of Z- t curve tidal variation. Distribution was quantified by the coefficient of variation (CV) and the heterogeneity index (HI). Both CV and HI of the tE and PHASE features were significantly increased in COPD compared with controls, and both related to spirometry and FOT resistance and reactance measurements. In contrast, distribution of the AMP feature showed no relationships with lung mechanics. These novel time-based EIT metrics of VH reflect complex lung mechanics in COPD and have the potential to allow real-time visualization of pulmonary physiology in spontaneously breathing subjects. NEW & NOTEWORTHY Pulmonary electrical impedance tomography (EIT) is a real-time imaging technique capable of monitoring ventilation with exquisite temporal resolution. We report novel, time-based EIT measurements that not only demonstrate ventilation heterogeneity in chronic obstructive pulmonary disease (COPD), but also reflect oscillatory lung mechanics. These EIT measurements are noninvasive, radiation-free, easy to obtain, and provide real-time visualization of the complex pathophysiology of COPD.

Sign in / Sign up

Export Citation Format

Share Document