The Application of Electrical Impedance Tomography During the Ventilator Weaning Process

Abstract

Background: This study proposes the investigation of electrical impedance tomography (EIT) as a useful predictor for ventilator weaning. Methods: The study design was a nested case-control study and patients who were admitted to the intensive care unit and underwent their first tracheal intubation were enrolled. Those who successfully completed ventilator weaning and extubation after the first spontaneous breathing trial (SBT) were included in the weaning success group, while those who did not pass the SBT or received secondary intubation within 48 hours were included in the weaning failure group. In both groups, EIT was adopted to record the monitoring data in three phases: before the SBT (pre-SBT), during the SBT (SBT), and after the SBT (post-SBT). Results: A total of 53 patients were enrolled, including 41 cases in the weaning success group and 12 cases in the weaning failure group. The logistic regression analysis showed that the pre-SBT global impedance (GI) and the SBT region of interest 2 (ROI2) were significantly higher in the weaning success group than in the weaning failure group (p = 0.0001 and p = 0.002). The pre-SBT GI predicted weaning success with a sensitivity of 0.524, a specificity of 0.818, a p-value of 0.0496, and a 95% confidence interval (CI) of 0.001-0.978. The sensitivity, specificity, p-value, and 95% CI for the SBT ROI2 were 1, 0.595, 0.0164, and 1.010-1.108, respectively. Conclusion: For patients without contraindications to EIT, the application of EIT is recommended to be added to the existing evaluation system for ventilator weaning, as it could help improve the weaning success rate. Further cohort studies are needed to investigate the actual efficacy of EIT after it has been added to the evaluation system.

Expert opinion document: “Electrical impedance tomography: applications from the intensive care unit and beyond”

“…Moon et al recently found that GI was significantly greater in patients failing a T-piece SBT, in a population of 40 patients either with ( n =16) or without ( n =24) diaphragm dysfunction [ 83 ]. In keeping with these previous results [ 81 – 83 ], in 53 patients mechanically ventilated for more than 72 h and undergoing their first T-piece SBT, Wang et al further confirmed that GI prior to SBT helps to predict SBT outcome [ 84 ].…”

Roles of electrical impedance tomography in lung transplantation

“…It was shown that in patients with an initial GI > 41.5, an SBT was more likely to fail, with a sensitivity of 87.5% and a specificity of 60.9%, which suggested that EIT could predict the failure of weaning. Wang et al found that the EIT may be a useful adjunctive tool for evaluating ventilator weaning using pre-SBT GI and SBT ROI 2 (four ROIs were divided from the ventral to dorsal, with ROI 2 being the second region) as predictors ( Wang et al, 2021 ). In addition to weaning failure due to pulmonary system dysfunction, phrenic nerve injury can also lead to atelectasis, difficult weaning, and prolonged ventilation in lung transplantation ( Hernández-Hernández et al, 2022 ).…”