Electrical Impedance Tomography Predicts Weaning Success in Adult Patients With Delayed Upper Abdominal Surgery: A Single-Center Retrospective Study

Objective: To evaluate the predictive value of electrical impedance tomography (EIT) in patients with delayed ventilator withdrawal after upper abdominal surgery.Methods: We retrospectively analyzed data of patients who were ventilated >24 h after upper abdominal surgery between January 2018 and August 2019. The patients were divided into successful (group S) and failed (group F) weaning groups. EIT recordings were obtained at 0, 5, 15, and 30 min of spontaneous breathing trials (SBTs) with SBT at 0 min set as baseline. We assessed the change in delta end-expiratory lung impedance and tidal volume ratio (ΔEELI/VT) from baseline, the change in compliance change percentage variation (|Δ(CW-CL)|) from baseline, the standard deviation of regional ventilation delay index (RVDSD), and global inhomogeneity (GI) using generalized estimation equation analyses. Receiver operating characteristic curve analyses were performed to evaluate the predictive value of parameters indicating weaning success.Results: Among the 32 included patients, ventilation weaning was successful in 23 patients but failed in nine. Generalized estimation equation analysis showed that compared with group F, the ΔEELI/VT was lower, and the GI, RVDSD, and (|Δ(CW-CL)|) were higher in group S. For predicting withdrawal failure, the areas under the curve of the ΔEELI/VT, (|Δ(CW-CL)|), and the RVDSD were 0.819, 0.918, and 0.918, and 0.816, 0.884, and 0.918 at 15 and 30 min during the SBTs, respectively.Conclusion: The electrical impedance tomography may predict the success rate of ventilator weaning in patients with delayed ventilator withdrawal after upper abdominal surgery.

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Monitoring intraoperative tidal volume distribution using electrical impedance tomography during upper abdominal surgery

European Journal of Anaesthesiology ◽

10.1097/00003643-201006121-00315 ◽

2010 ◽

Vol 27 ◽

pp. 99

Author(s):

M. S. Schaefer ◽

B. Bastin ◽

U. Schmalz ◽

V. Wania ◽

T. A. Treschan

Keyword(s):

Abdominal Surgery ◽

Tidal Volume ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Volume Distribution ◽

Impedance Tomography ◽

Upper Abdominal Surgery ◽

Upper Abdominal

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Electrical impedance tomography during major open upper abdominal surgery: a pilot-study

BMC Anesthesiology ◽

10.1186/1471-2253-14-51 ◽

2014 ◽

Vol 14 (1) ◽

Cited By ~ 16

Author(s):

Maximilian S Schaefer ◽

Viktoria Wania ◽

Bea Bastin ◽

Ursula Schmalz ◽

Peter Kienbaum ◽

...

Keyword(s):

Pilot Study ◽

Abdominal Surgery ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Impedance Tomography ◽

Upper Abdominal Surgery ◽

Upper Abdominal

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Effect of Electrical Impedance Tomography-Guided Early Mobilization in Patients After Major Upper Abdominal Surgery: Protocol for a Prospective Cohort Study

Frontiers in Medicine ◽

10.3389/fmed.2021.710463 ◽

2021 ◽

Vol 8 ◽

Author(s):

Xuan Song ◽

Daqiang Yang ◽

Maopeng Yang ◽

Yahu Bai ◽

Bingxin Qin ◽

...

Keyword(s):

Abdominal Surgery ◽

Electrical Impedance ◽

Early Mobilization ◽

Institutional Review Board ◽

Ventilation Distribution ◽

Impedance Tomography ◽

Upper Abdominal Surgery ◽

Institutional Review ◽

Before And After ◽

Upper Abdominal

Background: Pulmonary complications are common in patients after upper abdominal surgery, resulting in poor clinical outcomes and increased costs of hospitalization. Enhanced Recovery After Surgery Guidelines strongly recommend early mobilization post-operatively; however, the quality of the evidence is poor, and indicators for quantifying the effectiveness of early mobilization are lacking. This study will evaluate the effectiveness of early mobilization in patients undergoing an upper abdominal surgery using electrical impedance tomography (EIT). Specifically, we will use EIT to assess and compare the lung ventilation distribution among various regions of interest (ROI) before and after mobilization in this patient population. Additionally, we will assess the temporal differences in the distribution of ventilation in various ROI during mobilization in an effort to develop personalized activity programs for this patient population.Methods: In this prospective, single-center cohort study, we aim to recruit 50 patients after upper abdominal surgery between July 1, 2021 and June 30, 2022. This study will use EIT to quantify the ventilation distribution among different ROI. On post-operative day 1, the nurses will assist the patient to sit on the chair beside the bed. Patient's heart rate, blood pressure, oxygen saturation, respiratory rate, and ROI 1-4 will be recorded before the mobilization as baseline. These data will be recorded again at 15, 30, 60, 90, and 120 min after mobilization, and the changes in vital signs and ROI 1-4 values at each time point before and after mobilization will be compared.Ethics and Dissemination: The study protocol has been approved by the Institutional Review Board of Liaocheng Cardiac Hospital (2020036). The trial is registered at chictr.org.cn with identifier ChiCTR2100042877, registered on January 31, 2021. The results of the study will be presented at relevant national and international conferences and submitted to international peer-reviewed journals. There are no plans to communicate results specifically to participants. Important protocol modifications, such as changes to eligibility criteria, outcomes, or analyses, will be communicated to all relevant parties (including investigators, Institutional Review Board, trial participants, trial registries, journals, and regulators) as needed via email or in-person communication.

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A Modified Method to Assess Tidal Recruitment by Electrical Impedance Tomography

Journal of Clinical Medicine ◽

10.3390/jcm8081161 ◽

2019 ◽

Vol 8 (8) ◽

pp. 1161 ◽

Cited By ~ 3

Author(s):

Thomas Muders ◽

Benjamin Hentze ◽

Philipp Simon ◽

Felix Girrbach ◽

Michael R.G. Doebler ◽

...

Keyword(s):

Lung Injury ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Characteristic Curve ◽

Receiver Operator Characteristic Curve ◽

Positive End Expiratory Pressure ◽

Regional Ventilation ◽

Impedance Tomography ◽

Modified Method ◽

Tidal Recruitment

Avoiding tidal recruitment and collapse during mechanical ventilation should reduce the risk of lung injury. Electrical impedance tomography (EIT) enables detection of tidal recruitment by measuring regional ventilation delay inhomogeneity (RVDI) during a slow inflation breath with a tidal volume (VT) of 12 mL/kg body weight (BW). Clinical applicability might be limited by such high VTs resulting in high end-inspiratory pressures (PEI) during positive end-expiratory pressure (PEEP) titration. We hypothesized that RVDI can be obtained with acceptable accuracy from reduced slow inflation VTs. In seven ventilated pigs with experimental lung injury, tidal recruitment was quantified by computed tomography at PEEP levels changed stepwise between 0 and 25 cmH2O. RVDI was measured by EIT during slow inflation VTs of 12, 9, 7.5, and 6 mL/kg BW. Linear correlation of tidal recruitment and RVDI was excellent for VTs of 12 (R2 = 0.83, p < 0.001) and 9 mL/kg BW (R2 = 0.83, p < 0.001) but decreased for VTs of 7.5 (R2 = 0.76, p < 0.001) and 6 mL/kg BW (R2 = 0.71, p < 0.001). With any reduction in slow inflation VT, PEI decreased at all PEEP levels. Receiver-Operator-Characteristic curve analyses revealed that RVDI-thresholds to predict distinct amounts of tidal recruitment differ when obtained from different slow inflation VTs. In conclusion, tidal recruitment can sufficiently be monitored by EIT-based RVDI-calculation with a slow inflation of 9 mL/kg BW.

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The Role of Chest Electrical Impedance Tomography in the Pediatric Ventilator Weaning

Case Medical Research ◽

10.31525/ct1-nct04011852 ◽

2019 ◽

Author(s):

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Ventilator Weaning ◽

Impedance Tomography

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Abstract 293: Detection of Pseudo-Pulseless Electrical Activity with Electrical Impedance Tomography

Circulation ◽

10.1161/circ.142.suppl_4.293 ◽

2020 ◽

Vol 142 (Suppl_4) ◽

Author(s):

Alexander L Lindqwister ◽

Weiyi Wu ◽

Alexander Ivanov ◽

Ethan K Murphy ◽

Samuel B Klein ◽

...

Keyword(s):

Machine Learning ◽

Electrical Activity ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Characteristic Curve ◽

Pulseless Electrical Activity ◽

Training Data ◽

Mechanical Activity ◽

Electrode Arrays ◽

Impedance Tomography

Introduction: Pseudo-Pulseless Electrical Activity (p-PEA) is a lifeless form of profound cardiac shock characterized by measurable cardiac mechanical activity without clinically detectable pulses. p-PEA may constitute up to 40% of reported cases of cardiac arrest and its management may be different from ventricular fibrillation or even true-PEA. Currently, diagnosis of p-PEA requires either echocardiography or intravascular catheterization, neither of which are ideal in the prehospital setting. Electrical impedance tomography (EIT) uses skin surface electrodes to generate images based on cross sectional resistance. We investigated the ability of EIT and machine learning (ML) to detect p-PEA. Methods: Female swine (N = 14) under intravenous anesthesia were instrumented with aortic and central venous micromanometer catheters. p-PEA was induced by ventilation with 6% O 2 in 94% N 2 , defined as a systolic aortic pressure less than 40 mmHg. Continuous EIT renderings were obtained from circumferential thoracic and abdominal electrode arrays. A deep learning model was utilized to detect p-PEA using EIT sequences. Twelve pigs were randomly selected as training data and 2 pigs as a test set. EIT images were saved as 30 second clips, resulting in 3033 clips generated. To increase generalizability, random epochs ranging from 30 - 100% of the total clip length were generated, resulting in a model capable of detecting this disease state with limited video fragments. Results: This technique yielded a receiver operator characteristic curve - area under the curve (ROC-AUC) of 0.91 for detection of p-PEA in the testing dataset (Figure 1), with 84% accuracy, 88% sensitivity, and 84% specificity. Conclusions: EIT combined with machine learning may be able to reliably delineate p-PEA in a hypoxic porcine model. This approach may be promising for non-invasive operator-independent p-PEA detection.

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The Application of Electrical Impedance Tomography During the Ventilator Weaning Process

International Journal of General Medicine ◽

10.2147/ijgm.s331772 ◽

2021 ◽

Vol Volume 14 ◽

pp. 6875-6883

Author(s):

Guan Wang ◽

Lei Zhang ◽

Bin Li ◽

Bingyin Niu ◽

Jian Jiang ◽

...

Keyword(s):

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Ventilator Weaning ◽

Impedance Tomography

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Individual Positive End-expiratory Pressure Settings Optimize Intraoperative Mechanical Ventilation and Reduce Postoperative Atelectasis

Anesthesiology ◽

10.1097/aln.0000000000002435 ◽

2018 ◽

Vol 129 (6) ◽

pp. 1070-1081 ◽

Cited By ~ 59

Author(s):

Sérgio M. Pereira ◽

Mauro R. Tucci ◽

Caio C. A. Morais ◽

Claudia M. Simões ◽

Bruno F. F. Tonelotto ◽

...

Keyword(s):

Computed Tomography ◽

Abdominal Surgery ◽

Electrical Impedance Tomography ◽

Electrical Impedance ◽

Lung Protective Ventilation ◽

Positive End Expiratory Pressure ◽

Lung Collapse ◽

Tissue Mass ◽

Impedance Tomography ◽

Postoperative Atelectasis

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications after abdominal surgery. Although the protective role of a more physiologic tidal volume has been established, the added protection afforded by positive end-expiratory pressure (PEEP) remains uncertain. The authors hypothesized that a low fixed PEEP might not fit all patients and that an individually titrated PEEP during anesthesia might improve lung function during and after surgery. Methods Forty patients were studied in the operating room (20 laparoscopic and 20 open-abdominal). They underwent elective abdominal surgery and were randomized to institutional PEEP (4 cm H2O) or electrical impedance tomography–guided PEEP (applied after recruitment maneuvers and targeted at minimizing lung collapse and hyperdistension, simultaneously). Patients were extubated without changing selected PEEP or fractional inspired oxygen tension while under anesthesia and submitted to chest computed tomography after extubation. Our primary goal was to individually identify the electrical impedance tomography–guided PEEP value producing the best compromise of lung collapse and hyperdistention. Results Electrical impedance tomography–guided PEEP varied markedly across individuals (median, 12 cm H2O; range, 6 to 16 cm H2O; 95% CI, 10–14). Compared with PEEP of 4 cm H2O, patients randomized to the electrical impedance tomography–guided strategy had less postoperative atelectasis (6.2 ± 4.1 vs. 10.8 ± 7.1% of lung tissue mass; P = 0.017) and lower intraoperative driving pressures (mean values during surgery of 8.0 ± 1.7 vs. 11.6 ± 3.8 cm H2O; P < 0.001). The electrical impedance tomography–guided PEEP arm had higher intraoperative oxygenation (435 ± 62 vs. 266 ± 76 mmHg for laparoscopic group; P < 0.001), while presenting equivalent hemodynamics (mean arterial pressure during surgery of 80 ± 14 vs. 78 ± 15 mmHg; P = 0.821). Conclusions PEEP requirements vary widely among patients receiving protective tidal volumes during anesthesia for abdominal surgery. Individualized PEEP settings could reduce postoperative atelectasis (measured by computed tomography) while improving intraoperative oxygenation and driving pressures, causing minimum side effects.

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