Electrical impedance tomography monitoring during spontaneous breathing trial: Physiological description and potential clinical utility

2019 ◽  
Vol 63 (8) ◽  
pp. 1019-1027 ◽  
Author(s):  
Júlia N. G. Lima ◽  
Melissa S. Fontes ◽  
Tatiana Szmuszkowicz ◽  
Alexandre M. Isola ◽  
Alexandre T. Maciel
2021 ◽  
Vol 10 (2) ◽  
pp. 192
Author(s):  
Ekaterina Krauss ◽  
Daniel van der Beck ◽  
Isabel Schmalz ◽  
Jochen Wilhelm ◽  
Silke Tello ◽  
...  

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.


2012 ◽  
Vol 116 (6) ◽  
pp. 1227-1234 ◽  
Author(s):  
Oliver C. Radke ◽  
Thomas Schneider ◽  
Axel R. Heller ◽  
Thea Koch

Background Positive-pressure ventilation causes a ventral redistribution of ventilation. Spontaneous breathing during general anesthesia with a laryngeal mask airway could prevent this redistribution of ventilation. We hypothesize that, compared with pressure-controlled ventilation, spontaneous breathing and pressure support ventilation reduce the extent of the redistribution of ventilation as detected by electrical impedance tomography. Methods The study was a randomized, three-armed, observational, clinical trial without blinding. With approval from the local ethics committee, we enrolled 30 nonobese patients without severe cardiac or pulmonary comorbidities who were scheduled for elective orthopedic surgery. All of the procedures were performed under general anesthesia with a laryngeal mask airway and a standardized anesthetic regimen. The center of ventilation (primary outcome) was calculated before the induction of anesthesia (AWAKE), after the placement of the laryngeal mask airway (BEGIN), before the end of anesthesia (END), and after arrival in the postanesthesia care unit (PACU). Results The center of ventilation during anesthesia (BEGIN) was higher than baseline (AWAKE) in both the pressure-controlled and pressure support ventilation groups (pressure control: 55.0 vs. 48.3, pressure support: 54.7 vs. 48.8, respectively; multivariate analysis of covariance, P &lt; 0.01), whereas the values in the spontaneous breathing group remained at baseline levels (47.9 vs. 48.5). In the postanesthesia care unit, the center of ventilation had returned to the baseline values in all groups. No adverse events were recorded. Conclusions Both pressure-controlled ventilation and pressure support ventilation induce a redistribution of ventilation toward the ventral region, as detected by electrical impedance tomography. Spontaneous breathing prevents this redistribution.


2019 ◽  
Vol 4 (1) ◽  
pp. 38-44 ◽  
Author(s):  
T. Rahman ◽  
M.M Hasan ◽  
A. Farooq ◽  
M. Z. Uddin

Abstract Electrical Impedance Tomography (EIT) has successive wide range in impedance imaging, but still it is difficult to extract cardiac-related conductivity changes and respiratory-related conductivity changes in spontaneous breathing subjects. Quite a few methods are attempted to extract these two signals such as electrocardiogram gated averaging, frequency domain filtering and principal component analysis. However, such methods are not able to take apart these components properly or put some effort in real time imaging and have their own limitations. The purpose of this paper is to introduce a new method in the EIT clinical application field, Independent Component Analysis (ICA) to extract cardiac and respiratory related signals in electrical impedance tomography. Independent component analysis has been introduced to use in electrical impedance tomography but this is the first attempt ever to implement this method to separate these two signals and image those independent conductivity distribution of respiration and cardiac changes independently. Data has been collected from a spontaneous breathing subject. Filtration technique has been used to remove random noise and multi level spatial ICA has been applied to obtain independent component signals which has been later used in reconstruction algorithm for imaging.


Sign in / Sign up

Export Citation Format

Share Document