Lung distribution of gas and blood volume in critically ill COVID-19 patients: a quantitative dual-energy computed tomography study

• Published in: Critical care (London, England) England), 2021-06, Vol.25 (1), p.214-214, Article 214
• Main Authors: Ball, Lorenzo, Robba, Chiara, Herrmann, Jacob, Gerard, Sarah E, Xin, Yi, Mandelli, Maura, Battaglini, Denise, Brunetti, Iole, Minetti, Giuseppe, Seitun, Sara, Bovio, Giulio, Vena, Antonio, Giacobbe, Daniele Roberto, Bassetti, Matteo, Rocco, Patricia R M, Cereda, Maurizio, Rizi, Rahim R, Castellan, Lucio, Patroniti, Nicolò, Pelosi, Paolo
• Format: Article
• Language: English
• Subjects: Aged; ARDS; Blood; Blood Gas Analysis - methods; Blood Volume - physiology; Cohort Studies; Coronaviruses; COVID-19; COVID-19 - diagnostic imaging; COVID-19 - epidemiology; COVID-19 - metabolism; Critical care; Critical Illness - epidemiology; Dual energy computed tomography; Epidemiology; Female; Humans; Iodine; Italy - epidemiology; Lung - diagnostic imaging; Lung - metabolism; Lung imaging; Male; Middle Aged; Pandemics; Pneumonia; Pulmonary embolisms; Pulmonary Gas Exchange - physiology; Respiration, Artificial - methods; Retrospective Studies; Severe acute respiratory syndrome coronavirus 2; Tomography, X-Ray Computed - methods; Ventilation; Ventilators
• ISSN: 1364-8535; 1466-609X; 1364-8535; 1366-609X
• DOI: 10.1186/s13054-021-03610-9

Critically ill COVID-19 patients have pathophysiological lung features characterized by perfusion abnormalities. However, to date no study has evaluated whether the changes in the distribution of pulmonary gas and blood volume are associated with the severity of gas-exchange impairment and the type of respiratory support (non-invasive versus invasive) in patients with severe COVID-19 pneumonia. This was a single-center, retrospective cohort study conducted in a tertiary care hospital in Northern Italy during the first pandemic wave. Pulmonary gas and blood distribution was assessed using a technique for quantitative analysis of dual-energy computed tomography. Lung aeration loss (reflected by percentage of normally aerated lung tissue) and the extent of gas:blood volume mismatch (percentage of non-aerated, perfused lung tissue-shunt; aerated, non-perfused dead space; and non-aerated/non-perfused regions) were evaluated in critically ill COVID-19 patients with different clinical severity as reflected by the need for non-invasive or invasive respiratory support. Thirty-five patients admitted to the intensive care unit between February 29th and May 30th, 2020 were included. Patients requiring invasive versus non-invasive mechanical ventilation had both a lower percentage of normally aerated lung tissue (median [interquartile range] 33% [24-49%] vs. 63% [44-68%], p