Methods: Data from a prospective multi-institution StO₂ monitoring study were analyzed to determine the current epidemiology of MT (defined as transfusion volume ¡Ý10 units packed red blood cells in 24 hours of hospitalization). Multivariate logistic regression was used to develop prediction models.

Results: Seven US level I trauma centers (TC) enrolled 383 patients. 114 (30%) required MT. MT progressed rapidly (40% exceeded MT threshold 2 hours after TC arrival, 80% after 6 hours). One third of MT patients died. Two thirds of deaths were due to early exsanguination and two thirds of early exsanguination patients died within 6 hours. One third of the early MT survivors developed multiple organ dysfunction syndrome. MT could be predicted with standard, readily available clinical data within 30 minutes and 60 minutes of TC arrival (area under the receiver operating characteristic curve = 0.78 and 0.80). In patients who required MT, StO₂ was the only consistent predictor of poor outcome (multiple organ dysfunction syndrome or death).

Conclusion: MT progresses rapidly to significant morbidity and mortality despite level I TC care. Patients who require MT can be predicted early, and persistent low StO₂ identifies those MT patients destined to have poor outcome. The ultimate goal is to identify these high risk patients as early as possible to test new strategies to improve outcome. Further validation studies are needed to analyze appropriate allocation and study appropriate use of damage control interventions.