Peripheral eosinophilia is associated with non-classical radiological patterns in acute respiratory distress syndrome

<bold>Background:</bold> The natural history of severe acute respiratory distress syndrome (ARDS) displays diverse longitudinal patterns on computed tomography (CT). We investigate traits which define two such patterns: non-dependent consolidation (NDC) and traction bronchiectasis (TrB). <bold>Aims and Objectives:</bold> To describe the prevalence, associations, and outcomes of NDC and TrB in patients with ARDS. <bold>Methods:</bold> Serial CT scans from 100 consecutive patients with ARDS on extracorporeal membrane oxygenation (ECMO) between 2018 and 2020 were included. Scans were scored for presence or absence of NDC and TrB (n=210). Multiple logistic regression was used to characterise associations between white cell differential count and each radiological phenotype. <bold>Results:</bold> 25 (12%) scans showed prevalent pattern NDC (extent of NDC >50% of consolidation) and 61 scans (30.5%) showed TrB. Baseline characteristics (age, sex and BMI, PEEP and peak inspiratory pressure) were comparable between groups. Using multiple regression, peripheral eosinophilia was associated with NDC (OR 3.5, p=0.02) and TrB (OR 5.4, p=0.003), but no other associations between white cell differentials and these radiological patterns were seen. Patients with TrB on their last scan spent more median days on ECMO (31 [20.5-36.5]) than those without (17 [12-27], p=0.001). No other difference in outcomes was seen between groups. <bold>Conclusions:</bold> Peripheral blood eosinophilia is associated with NDC and TrB patterns in ARDS CT scans. Further validation of these radiological patterns is required.