BACKGROUND: The dominant feature of COVID-19-associated ARDS is gas exchange impairment. Extravascular lung water index is a surrogate for lung edema and reflects the level of alveolocapillary disruption. The primary aim was the prediction of extravascular lung water index by the alveolar-arterial oxygen difference. The secondary aims were in determining the relationship between the extravascular lung water index and other oxygenation parameters, the [Formula: see text], end-tidal oxygen concentration, pulmonary oxygen gradient ([Formula: see text] minus end-tidal oxygen concentration), and [Formula: see text]. METHODS: This observational prospective single-center study was performed at the Department of Anaesthesiology and Intensive Care, The University Hospital in Ostrava, The Czech Republic, during the COVID-19 pandemic, from March 20, 2020, until May 24, 2021. RESULTS: The relationship between the extravascular lung water index and alveolar-arterial oxygen difference showed only a mild-to-moderate correlation (r = 0.33, P < .001). Other extravascular lung water index correlations were as follows: [Formula: see text] (r = 0.33, P < .001), end-tidal oxygen concentration (r = 0.26, P = .0032), [Formula: see text] minus end-tidal oxygen concentration (r = 0.15, P = .0624), and [Formula: see text] (r = -0.15, P = .01). CONCLUSIONS: The alveolar-arterial oxygen difference does not reliably correlate with the extravascular lung water index and the degree of lung edema in COVID-19-associated ARDS.

Department of Anaesthesiology and Intensive Care Medicine University Hospital Ostrava and Faculty of Medicine University of Ostrava Ostrava Czech Republic

Department of Infectious Diseases University Hospital Ostrava Ostrava Czech Republic

Department of Pediatric Anaesthesiology and Intensive Care Medicine University Hospital Brno and Faculty of Medicine Masaryk University Brno Czech Republic

Department of Surgical Studies University Hospital Ostrava Ostrava Czech Republic

Institute for Research and Applications of Fuzzy Modeling Centre of Excellence IT4Innovations University of Ostrava Ostrava Czech Republic

Institute of Physiology and Pathophysiology Faculty of Medicine University of Ostrava Ostrava Czech Republic

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