Impact of EIT-based regional ventilation distribution on outcomes in different types of critical illness: a retrospective cohort study

BACKGROUND: Electrical impedance tomography (EIT) is a non-invasive bedside tool for real-time regional ventilation data, but its correlation with outcomes in different critical illnesses remains unclear. METHODS: This retrospective study included 108 ICU patients (liver disease, n = 48; respiratory failure, n = 36; gastrointestinal bleeding, n = 24) who underwent EIT monitoring between December 2023 and March 2025. EIT measured tidal volume percentage in four regions of interest (ROIs), with 28-day mortality as the primary outcome. Multivariate logistic regression adjusted for key confounders was used for analysis. RESULTS: Ventilation distribution patterns differed significantly among the three disease groups. The liver disease group showed predominant ventilation in ROI 1-2 (anterior regions), with a mean dorsal-to-ventral ratio (DVR) of 0.41 ± 0.18. The respiratory failure group exhibited more homogeneous distribution with a DVR of 0.76 ± 0.34. Patients with higher ventilation heterogeneity (coefficient of variation > 40%) had significantly higher 28-day mortality (29.5% vs 16.7%, p = 0.022), longer duration of mechanical ventilation (8.7 vs 5.4 days, p = 0.012), and fewer ventilator-free days (14.3 vs 19.6 days, p = 0.009). Multivariate analysis identified DVR < 0.4 (OR 2.84, 95% CI 1.46-5.53, p = 0.002) and ventilation heterogeneity (OR 2.31, 95% CI 1.18-4.52, p = 0.014) as independent predictors of 28-day mortality after adjusting for disease severity, age, and mechanical ventilation parameters. CONCLUSIONS: Regional ventilation patterns vary by underlying disease. Greater heterogeneity and lower DVR independently correlate with worse outcomes. EIT-derived parameters may be prognostic indicators and therapeutic targets for optimizing ventilation in critical illness.