Subphenotype–Specific Risk of Intracranial Hemorrhage During Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome

This study compared the incidence of intracranial hemorrhage (ICH) among three previously identified acute respiratory distress syndrome (ARDS) subphenotypes: fibrotic, dry, and wet. This retrospective, multicenter observational study used a Japanese database of adult patients with severe ARDS supported with venovenous extracorporeal membrane oxygenation (VV ECMO). The Fine-Gray competing risk models were applied with inverse probability of treatment weighting (IPTW) to evaluate the impact of ARDS subphenotypes on ICH incidence. Of 536 patients included in the analysis, 185 (34.5%) were classified as fibrotic, 185 (34.5%) as dry, and 166 (31.0%) as wet. Intracranial hemorrhage occurred in 3.7% (20/536) of patients during VV ECMO support and was associated with significantly higher mortality compared with patients without ICH (65.0% [13/20] vs. 27.5% [142/516]; p < 0.001). Intracranial hemorrhage incidence was 8.7% (16/185), 0.5% (1/185), and 1.8% (3/166) in the fibrotic, dry, and wet groups, respectively, with a significantly higher incidence in the fibrotic group (p < 0.001). The fibrotic type was independently associated with a higher ICH risk compared with the other two types (hazard ratio: 4.33, 95% confidence interval: 1.47-12.69; p = 0.015). Severe ARDS cases classified as fibrotic had a significantly higher ICH risk during VV ECMO, highlighting the need for increased vigilance in this subgroup.