The epidemiology of noncompressible torso hemorrhage in the wars in Iraq and Afghanistan

Background: Noncompressible torso hemorrhage (NCTH) is the leading cause of potentially survivable trauma in the battlefield and has recently been defined using anatomic and physiologic criteria. The objective of this study was to characterize the frequency and mortality in combat of NCTH using a contemporary definition. Methods: Four categories of torso injury, each based on vascular disruption, were identified in US military casualties from the Department of Defense Trauma Registry (2002-2010): (1) thoracic, including lung; (2) solid organ (high-grade spleen, liver, and kidney); (3) named axial vessel; and (4) pelvic fracture with ring disruption. Injuries within these categories were evaluated in the context of physiologic indicator of shock and/or the need for operative hemorrhage control. Results: Of 15,209 battle injuries sustained during the study period, 12.7% (n = 1,936) had sustained one or more categories of torso injury. Of these, 331 (17.1%) had evidence of shock or the need for urgent hemorrhage control, with a mean (SD) Injury Severity Score (ISS) and mortality rate of 30 (13) and 18.7%, respectively. Pulmonary injuries were most numerous (41.7%), followed by solid-organ (29.3%), vascular (25.7%), and pelvic (15.1%) injuries. Following multivariate analysis, the most mortal injury complexes were identified as major arterial injury (odds ratio, 3.38; 95% confidence interval, 1.17-9.74) and pulmonary injury (odds ratio, 2.23; 95% confidence interval, 1.23-4.98). Conclusion: NCTH can be defined using anatomic parameters combined with physiologic and operative interventions suggestive of hemorrhage. Major arterial and pulmonary injuries contribute most significantly to the mortality burden.