Brian J. Eastridge

Understanding the epidemiology of death after battlefield injury is vital to combat casualty care performance improvement. The current analysis was undertaken to develop a comprehensive perspective of deaths that occurred after casualties reached a medical treatment facility. Battle injury died of wounds (DOW) deaths that occurred after casualties reached a medical treatment facility from October 2001 to June 2009 were evaluated by reviewing autopsy and other postmortem records at the Office of the Armed Forces Medical Examiners (OAFME). A panel of military trauma experts classified the injuries as nonsurvivable (NS) or potentially survivable (PS), in consultation with an OAFME forensic pathologist. Data including demographics, mechanism of injury, physiologic and laboratory variables, and cause of death were obtained from the Joint Theater Trauma Registry and the OAFME Mortality Trauma Registry. DOW casualties (n = 558) accounted for 4.56% of the nonreturn to duty battle injuries over the study period. DOW casualties were classified as NS in 271 (48.6%) cases and PS in 287 (51.4%) cases. Traumatic brain injury was the predominant injury leading to death in 225 of 271 (83%) NS cases, whereas hemorrhage from major trauma was the predominant mechanism of death in 230 of 287 (80%) PS cases. In the hemorrhage mechanism PS cases, the major body region bleeding focus accounting for mortality were torso (48%), extremity (31%), and junctional (neck, axilla, and groin) (21%). Fifty-one percent of DOW casualties presented in extremis with cardiopulmonary resuscitation upon presentation. Hemorrhage is a major mechanism of death in PS combat injuries, underscoring the necessity for initiatives to mitigate bleeding, particularly in the prehospital environment.

Derived from the necessity to improve the outcomes of soldiers injured on the battlefield, the U.S. military forces developed and implemented the Joint Theater Trauma System (JTTS) and the Joint Theater Trauma Registry based on U.S. civilian trauma system models. The purpose of this analysis was to develop battlefield injury outcome benchmark metrics and to evaluate the impact of JTTS-driven performance improvement interventions. To quantify these achievements, the Joint Theater Trauma Registry captured mechanistic, physiologic, diagnostic, therapeutic, and outcome data on 18,377 injured patients from January 2004 to May 2008 for analysis. Benchmarks were developed and statistically validated by using control chart methodology. The majority (66.4%) of battlefield wounds were penetrating mechanism, 23.3% of all patients had an Injury Severity Score of ≥16, 21.8% had a base deficit of ≥5, 30.5% of patients required blood, and 6.8% required massive transfusion (≥10 units red blood cell per 24 hours). In this severely injured population from the battlefield, the JTTS developed several pertinent benchmark metrics to assess quality of care associated with postinjury complications and mortality. The implementation of 27 JTTS-developed evidenced-based clinical practice guidelines and an improved information dissemination process was associated with a decrease in aggregate postinjury complications by 54%. Despite the numerous challenges of a global trauma system, the JTTS has set the standard for trauma care on the modern battlefield utilizing evidence-based medicine. The development of injury care benchmarks enhanced the evolution of the combat casualty care performance improvement process within the trauma system.

Background: Forward Surgical Teams (FST) provide forward deployed surgical care within the battle space. The next level of care in theater, the Combat Support Hospitals (CSH), are distinguished from the FST by advanced resource capabilities including more complex diagnostic imaging, laboratory support with blood banking, and intensive care units. This study was intended to assess the effect of FST capability on the outcome of seriously injured casualties in comparison to the CSH. Methods: We reviewed all casualty records in the Joint Theater Trauma Registry database from April 2004 to April 2006. The study cohort included all US military battle casualties who were admitted to either a FST or a CSH and were not returned to duty within 72 hours. Data were tabulated and assessed for basic demographics, mechanism of injury, injury severity score, ventilator and critical care days, and mortality. Statistical inferences were made using Chi square and Student’s t tests. Results: As of April 2006, the above information was available in the Joint Theater Trauma Registry on 2,617 US military battle casualties who survived to reach care at a FST and/or CSH. Of this population, 77 subsequently died of wounds and 2,540 survived. We found no significant difference in died of wounds rates between the sample populations or rates of ventilator or critical care days between the two groups, nor did controlling for injury severity score alter this picture. The most significant predictor of mortality in both these groups was head injury. Conclusions: The disparity between the availability of the highest level of injury care and the ability to care for injury as soon as possible is an issue of central importance to both the civilian and military trauma care communities. Our analysis demonstrates that despite the operational and logistic challenges that burden the FST, this level of surgical care confers equivalent battlefield injury outcome results compared with the CSH.

Clinicians routinely refer to hypotension as a systolic blood pressure (SBP) ≤90 mm Hg. However, few data exist to support the rigid adherence to this arbitrary cutoff. We hypothesized that the physiologic hypoperfusion and mortality outcomes classically associated with hypotension were manifest at higher SBPs. A total of 870,634 patient records from the National Trauma Data Bank with emergency department SBP and mortality data were analyzed. Patients (140,898) with severe head injuries, a Glasgow Coma Score ≤8, and base deficit (BD) <5, or missing data items were excluded from analysis. Admission BD, as a measure of metabolic hypoperfusion, was evaluated in 81,134 patients and mortality was plotted against SBP. Baseline mortality was <2.5%. However, at 110 mm Hg, the slope of the mortality curve increased such that mortality was 4.8% greater for every 10-mm Hg decrement in SBP. This effect was consistent to a maximum of 26% mortality at a SBP of 60 mm Hg. Hypoperfusion (change in the slope of BD curve) began to increase above baseline of 4.5 at a SBP 118 mm Hg. Taking the BD and mortality measurements together, this analysis shows that a SBP ≤110 mm Hg is a more clinically relevant definition of hypotension and hypoperfusion than is 90 mm Hg. This analysis will also be useful for developing appropriately powered studies of hemorrhagic shock.

Background: Medical lessons learned from Vietnam and previous military conflicts led to the development of civilian trauma systems in the United States. Operation Iraqi Freedom represents the first protracted, large-scale, armed conflict since the advent of civilian trauma systems in which to evaluate a similar paradigm on the battlefield. Methods: Collaborative efforts between the joint military forces of the United States initiated development of a theater trauma system in May 2004. Formal implementation of the system occurred in November 2004, the collaborative effort of the three Surgeons General of the U.S. military, the United States Army Institute of Surgical Research, and the American College of Surgeons Committee on Trauma. One trauma surgeon (Trauma System Director) and a team of six trauma nurse coordinators were deployed to theater to evaluate trauma system component issues. Demographic, mechanistic, physiologic, diagnostic, therapeutic, and outcome data were gathered for 4,700 injured patients using the Joint Theater Trauma Registry. Interview and survey methods were utilized to evaluate logistic aspects of the system. Results: System implementation identified more than 30 systemic issues requiring policy development, research, education, evaluation of medical resource allocation, and alterations in clinical care. Among the issues were transfer of casualties from point of injury to the most appropriate level of care, trauma clinical practice guidelines, standard forms, prophylactic antibiotic regimens, morbidity/mortality reporting, on-line medical evacuation regulation, improved data capture for the trauma registry, and implementation of a performance improvement program. Conclusions: The implementation of a theater trauma system demonstrated numerous opportunities to improve the outcome of soldiers wounded on the battlefield.