Monitoring postoperative lung recovery using electrical impedance tomography in post anesthesia care unit: an observational study

AbstractWith electrical impedance tomography (EIT) recruitment and de-recruitment phenomena can be quantified and monitored at bedside. The aim was to examine the feasibility of EIT with respect to monitor atelectasis formation and resolution in the post anesthesia care unit (PACU). In this observational study, 107 postoperative patients were investigated regarding the presence and recovery of atelectasis described by the EIT-derived parameters Global Inhomogeneity Index (GI Index), tidal impedance variation (TIV), and the changes in end-expiratory lung impedance (ΔEELI). We examined whether the presence of obesity (ADP group) has an influence on pulmonary recovery compared to normal weight patients (NWP group). During the stay at PACU, measurements were taken every 15 min. GI Index, TIV, and ΔEELI were calculated for each time point. 107 patients were monitored and EIT-data of 16 patients were excluded for various reasons. EIT-data of 91 patients were analyzed off-line. Their length of stay averaged 80 min (25th and 75th quartile 52–112). The ADP group demonstrated a significantly higher GI Index at PACU arrival (p < 0.001). This finding disappeared during their stay at the PACU. Additionally, the ADP group showed a significant increase in ΔEELI between PACU arrival and discharge (p = 0.025). Furthermore, TIV showed a significantly lower value during the first 90 min of PACU stay as compared to the time period thereafter (p = 0.036). Our findings demonstrate that obesity has an influence on intraoperative atelectasis formation and de-recruitment during PACU stay. The application of EIT in spontaneously breathing PACU patients seems meaningful in monitoring pulmonary recovery.

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Evaluation of Regional Pulmonary Ventilation in Spontaneously Breathing Patients with Idiopathic Pulmonary Fibrosis (IPF) Employing Electrical Impedance Tomography (EIT): A Pilot Study from the European IPF Registry (eurIPFreg)

Journal of Clinical Medicine ◽

10.3390/jcm10020192 ◽

2021 ◽

Vol 10 (2) ◽

pp. 192

Author(s):

Ekaterina Krauss ◽

Daniel van der Beck ◽

Isabel Schmalz ◽

Jochen Wilhelm ◽

Silke Tello ◽

...

Keyword(s):

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Electrical Impedance Tomography ◽

Spontaneous Breathing ◽

Electrical Impedance ◽

Statistical Significance ◽

Pulmonary Ventilation ◽

Healthy Controls ◽

Impedance Tomography ◽

Spontaneously Breathing

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.

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Electrical Impedance Tomography for Assessment of Pendelluft and Work of Breathing in Spontaneously Breathing Mechanically Ventilated Patients

10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a2803 ◽

2021 ◽

Author(s):

E. Kistler ◽

M.S. Schaefer ◽

E. Baedorf Kassis

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Work Of Breathing ◽

Impedance Tomography ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Spontaneously Breathing ◽

Ventilated Patients

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Freezing resistance evaluation of rose stems during frost dehardening using electrical impedance tomography

10.21203/rs.3.rs-107439/v1 ◽

2020 ◽

Author(s):

Ji Qian ◽

Juan Zhou ◽

Juan Rui Gong ◽

Yang Liu ◽

Gang Zhang

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Freezing Resistance ◽

Impedance Tomography ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses ◽

Impedance Variation ◽

Destructive Measurement ◽

Non Destructive ◽

Best Fit

Abstract Background Electrical impedance tomography (EIT) has rarely been applied in plant science, particularly to study plant resistance to abiotic and biotic stresses. In this study, we evaluated the freezing resistance of floribunda roses (Rosa Floribunda) during frost dehardening using the EIT technique to identify a new method for rapid and non-destructive measurement of plant freezing resistance. Results The current was the excitation source, the boundary voltage value was measured, and then the boundary voltage reconstructed value was formed. Using an imaging algorithm, the two-dimensional (2D) distribution of impedance or impedance variation is reconstructed. The EIT reconstructed values decreased obviously with the decline in freezing temperatures. The EIT reconstructed values of stems had the best fit to the logistic equation, and subsequently, the semi-lethal temperatures were calculated. The freezing resistance results evaluated using EIT reconstructed values were linearly correlated with the results of the traditional electrolyte leakage (EL) method (r = 0.93, P<0.01). Conclusions In conclusion, after freezing tests, the reconstructed values of EIT images could be used to quantitatively evaluate the freezing resistance of floribunda rose stems. The present study provides a reference for the further application of the EIT technique for non-destructive and rapid detection of plant freezing resistance.

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