Electrical impedance tomography is feasible to assess regional ventilation abnormalities in post-COVID-19 outpatients

Individuals with post-COVID-19 syndrome (PCS) frequently experience subjective dyspnea, while conventional diagnostic methods often fail to detect underlying abnormalities. Electrical impedance tomography (EIT) is a non-invasive imaging modality that enables dynamic real-time assessment of regional lung ventilation. This study aimed to determine whether EIT-derived ventilation abnormalities are associated with PCS and with self-reported dyspnea among patients with PCS. In this prospective, observational study, we included 100 spontaneously breathing patients and 50 healthy controls. Visual qualitative and MATLAB-derived quantitative EIT parameters were developed and investigated in logistic regression modelling. Patients were more likely to exhibit uneven ventilation distribution (adjusted OR [95% CI], 4.71 [1.66, 13.41]), non-ventilated areas (16.05 [6.42, 40.13]), concave lung rim (7.53 [3.31, 17.15]) and conspicuous lung appearance (5.25 [2.31, 11.90]) than healthy controls. Counter ventilation (95th percentile) (0.87 [(0.76, 0.99]) and RVD SD (0.86 [0.80, 0.92]) were decreased, while RVD (1.08 [1.02, 1.15]) and ventilation asynchrony (SD) (1.35 [1.01, 1.82]) were increased. In PCS subgroup, no statistically significant association with subjective dyspnea was identified. Patients with PCS frequently exhibit EIT-detectable regional ventilation abnormalities, highlighting EIT’s potential as a non-invasive diagnostic tool for assessing regional lung ventilation. These findings warrant further validation in longitudinal studies.