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Physiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>The effects of obesity on pulmonary gas and blood distribution in patients with acute respiratory failure remain unknown. Dual-energy computed tomography (DECT) is a X-ray-based method used to study regional distribution of gas and blood within the lung. We hypothesized that 1) regional gas\/blood mismatch can be quantified by DECT; 2) obesity influences the global and regional distribution of pulmonary gas and blood; 3) regardless of ventilation modality (invasive vs. non-invasive ventilation), patients\u2019 body mass index (BMI) has an impact on pulmonary gas\/blood mismatch.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>This single-centre prospective observational study enrolled 118 hypoxic COVID-19 patients (92 male) in need of respiratory support and intensive care who underwent DECT. The cohort was divided into three groups according to BMI: 1. BMI&amp;lt;25\u00a0kg\/m<jats:sup>2<\/jats:sup> (non-obese), 2. BMI = 25\u201340\u00a0kg\/m<jats:sup>2<\/jats:sup> (overweight to obese), and 3. BMI&amp;gt;40\u00a0kg\/m<jats:sup>2<\/jats:sup> (morbidly obese). Gravitational analysis of Hounsfield unit distribution of gas and blood was derived from DECT and used to calculate regional gas\/blood mismatch. A sensitivity analysis was performed to investigate the influence of the chosen ventilatory modality and BMI on gas\/blood mismatch and adjust for other possible confounders (i.e., age and sex).<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>1) Regional pulmonary distribution of gas and blood and their mismatch were quantified using DECT imaging. 2) The BMI&amp;gt;40\u00a0kg\/m<jats:sup>2<\/jats:sup> group had less hyperinflation in the non-dependent regions and more lung collapse in the dependent regions compared to the other BMI groups. In morbidly obese patients, gas and blood were more evenly distributed; therefore, the mismatch was lower than in other patients (30% vs. 36%, <jats:italic>p<\/jats:italic> &amp;lt; 0.05). 3) An increase in BMI of 5\u00a0kg\/m<jats:sup>2<\/jats:sup> was associated with a decrease in mismatch of 3.3% (CI: 3.67% to \u22122.93%, <jats:italic>p<\/jats:italic> &amp;lt; 0.05). Neither the ventilatory modality nor age and sex affected the gas\/blood mismatch (<jats:italic>p<\/jats:italic> &amp;gt; 0.05).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>1) In a hypoxic COVID-19 population needing intensive care, pulmonary gas\/blood mismatch can be quantified at a global and regional level using DECT. 2) Obesity influences the global and regional distribution of gas and blood within the lung, and BMI&amp;gt;40\u00a0kg\/m<jats:sup>2<\/jats:sup> improves pulmonary gas\/blood mismatch. 3) This is true regardless of the ventilatory mode and other possible confounders, i.e., age and sex.<\/jats:p><\/jats:sec><jats:sec><jats:title>Trial Registration<\/jats:title><jats:p><jats:ext-link>Clinicaltrials.gov<\/jats:ext-link>, identifier NCT04316884, NCT04474249.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fphys.2024.1399407","type":"journal-article","created":{"date-parts":[[2024,7,10]],"date-time":"2024-07-10T05:06:21Z","timestamp":1720587981000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":6,"title":["Body mass index is associated with pulmonary gas and blood distribution mismatch in COVID-19 acute respiratory failure. 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