Characteristics of the pulmonary opacities on chest CT associated with difficulty in short-term liberation from veno-venous ECMO in patients with severe ARDS

Background It is clinically important to predict difficulty in short-term liberation from veno-venous extracorporeal membrane oxygenation (V-V ECMO) in patients with severe acute respiratory distress syndrome (ARDS) at the time of initiation of the support. The aim of this study was to identify the characteristics of pulmonary opacities on chest CT that is associated with difficulty in short-term liberation from V-V ECMO (< 14 days). Methods This multicenter retrospective study was conducted in adult patients initiated on V-V ECMO for severe ARDS between January 2014 and June 2022. The pulmonary opacities on CT at the time of initiation of the ECMO support were evaluated in a blinded manner, focusing on the following three characteristics of the opacities: (1) their distribution (focal/diffuse on the dorso-ventral axis or unilateral/bilateral on the left-right axis); (2) their intensity (pure ground glass/pure consolidation/mixed pattern); and (3) the degree of fibroproliferation (signs of traction bronchiectasis or reticular opacities). Results Among the 153 patients, 72 (47%) were successfully liberated from ECMO in the short term, while short-term liberation failed in the remaining 81 (53%) patients. Multivariate logistic regression analysis showed that the presence of mixed-pattern pulmonary opacities and signs of traction bronchiectasis, but not the distribution of the opacities, were independently associated with difficulty in short-term liberation (OR [95% CI]; 4.8 [1.4–16.5] and 3.9 [1.4–11.2], respectively). Conclusions The presence of a mixed pattern of the pulmonary opacities and signs of traction bronchiectasis on the chest CT were independently associated with difficulty in short-term liberation from V-V ECMO in severe ARDS patients.