Comparison of regional lung mechanics using electrical impedance tomography in mechanically ventilated COVID-19 vs pre-pandemic patients: A retrospective study

Abstract

Background: Whether coronavirus disease 2019 acute respiratory distress syndrome (COVID-ARDS) and acute respiratory distress syndrome (ARDS) have a different phenotype remains subject of research and debate. We aimed to study the differences and similarities of electrical impedance tomography (EIT) parameters in patients with and without COVID-19.

Methods: This retrospective observational study included patients with an EIT measurement during ICU admission. EIT variables, including dynamic compliance, alveolar overdistension and collapse, were visualized for each positive end-expiratory pressure (PEEP) level of the EIT measurement using polynomial regression. Two-level linear mixed-effects regression with random intercept and slope for PEEP was performed for alveolar overdistension per PEEP level during EIT measurement in COVID-19 and non-COVID-19 patients.

Results: From October 2013 until October 2023, 131 COVID-19 patients and 128 non-COVID-19 patients underwent an EIT measurement. The overall pattern of dynamic compliance, alveolar overdistension and collapse was similar in COVID-19 and non-COVID-19 patients. Visual inspection of EIT variables showed a higher mean alveolar overdistension in COVID-19 patients compared to the non-COVID-19 patients (day 1-3: maximum 43.2 % vs maximum 26.1 %, day 4-6: maximum 46.8 % vs maximum 25.2 %, ≥7 days: maximum 41.4 % vs maximum 33.0 %). However, two-level linear mixed-effects regression with random intercept and slope for PEEP showed no statistically significant difference between COVID-19 and non-COVID-19 patients (-1.0 % [-3.5; 1.6], p = 0.459).

Conclusions: Regional lung dynamics were generally comparable in COVID-19 and non-COVID-19 patients when assessed by EIT. Based on these findings, mechanical ventilation protocols should be optimized for comparable parameters in COVID-19 and non-COVID-19 patients.

Keywords: Coronavirus Disease-19; Electrical impedance tomography; Mechanical ventilation; Positive end-expiratory pressure; Ventilator-induced lung injury.