The effect of prehospital transport time, injury severity, and blood transfusion on survival of US military casualties in Iraq

Abstract

Background: Reducing time from injury to care can optimize trauma patient outcomes. A previous study of prehospital transport of US military casualties during the Afghanistan conflict demonstrated the importance of time and treatment capability for combat casualty survival.

Methods: A retrospective descriptive analysis was conducted to analyze battlefield data collected on US military combat casualties during the Iraq conflict from March 19, 2003, to August 31, 2010. All casualties were analyzed by mortality outcome (killed in action, died of wounds, case fatality rate) and compared with Afghanistan conflict. Detailed data for those who underwent prehospital transport were analyzed for effects of transport time, injury severity, and blood transfusion on survival.

Results: For the total population, percent killed in action (16.6% vs. 11.1%), percent died of wounds (5.9% vs. 4.3%), and case fatality rate (10.0 vs. 8.6) were higher for Iraq versus Afghanistan (p < 0.001). Among 1,692 casualties (mean New Injury Severity Score, 22.5; mortality, 17.6%) with detailed data, the injury mechanism included 77.7% from explosions and 22.1% from gunshot wounds. For prehospital transport, 67.6% of casualties were transported within 60 minutes, and 32.4% of casualties were transported in greater than 60 minutes. Although 97.0% of deaths occurred in critical casualties (New Injury Severity Score, 25-75), 52.7% of critical casualties survived. Critical casualties were transported more rapidly (p < 0.01) and more frequently within 60 minutes (p < 0.01) than other casualties. Critical casualties had lower mortality when blood was received (p < 0.01). Among critical casualties, blood transfusion was associated with survival irrespective of transport time within or greater than 60 minutes (p < 0.01).

Conclusion: Although data were limited, early blood transfusion was associated with battlefield survival in Iraq as it was in Afghanistan.

Level of evidence: Performance improvement and epidemiological, level IV.