Defining Rotational Thromboelastometry Thresholds for Fibrinolysis Phenotyping and Massive Transfusion Prediction in Trauma

Introduction Fibrinolysis, or clot breakdown, is a major contributor to death in severely injured patients. Thromboelastography (TEG) has established cutoffs for fibrinolysis phenotypes, hyperfibrinolysis, physiologic fibrinolysis, and fibrinolytic shutdown, but analogous thresholds for rotational thromboelastometry (ROTEM) remain limited. This study aimed to characterize fibrinolysis phenotypes using ROTEM and identify predictors of massive transfusion (MT) in trauma patients.Methods Among 2474 trauma patients who underwent ROTEM testing at an adult level I trauma center from 2018 to 2024, 2257 had an available EXTEM maximum lysis (ML) value and were included in the fibrinolysis phenotype analysis. Patients were categorized by EXTEM ML: shutdown (ML 15%). The primary outcome was MT within 4 h; secondary outcomes included 24-h transfusion requirements, length of stay, and mortality.Results The median age was 46 y; 70.9% were male, and the median Injury Severity Score was 24.3. Hyperfibrinolysis occurred in 5.3% (n = 119), physiologic fibrinolysis in 64.6% (n = 1458), and shutdown in 30.1% (n = 680). Mortality was highest in hyperfibrinolysis (58.0%; 95% confidence interval [CI]: 49.0-66.5%) versus physiologic (10.6%; 95% CI: 9.2-12.3%) and shutdown (20.4%; 95% CI: 17.6-23.6%) (P Conclusions This study externally validates previously described ROTEM-specific EXTEM ML thresholds for fibrinolysis phenotyping in an independent trauma cohort. Hyperfibrinolysis strongly predicted MT and was associated with high mortality, whereas shutdown identified a distinct high-risk group. These findings support integration of ROTEM-specific fibrinolysis criteria into trauma protocols and prospective evaluation of phenotype-directed resuscitation strategies.