B. W. Bonds1,2, M. J. Bradley3,4, S. S. Cai2, D. M. Stein1,2 3Naval Medical Research Center,Regenerative Medicine,Silver Spring, MD, USA 4Walter Reed Army Medical Center,Washington, DC, USA 1R Adams Cowley Shock Trauma Center,Trauma Surgery,Baltimore, MD, USA 2University Of Maryland,School Of Medicine,Baltimore, MD, USA
Introduction: Motor vehicle collisions (MVC) are one of the main mechanisms for traumatic brain injury (TBI) in the United States. In 2009, regulations modifying side impact crash testing from the National Highway Traffic Safety Administration were announced which effectively mandated the inclusion of side impact airbags on all vehicles as well as structural reinforcements aimed at minimizing sidewall intrusion. We sought to determine any effect these changes have had on the mortality, frequency and severity of TBI following MVC.
Methods: Data was retrospectively collected over ten years (2004-2013) on all patients admitted to a level one trauma center with a TBI following MVC. Patients were reviewed for severity of brain injury, post-resuscitation Glasgow Coma Scale (GCS), and mortality. The incidence of mild (GCS 13-15), moderate (GCS 9-12), and severe TBI (GCS ≤ 8) was calculated five years before (2004-08) and after (2009-13) the new regulations with a p-value < 0.05 considered significant.
Results: Over ten years, 2144 patients were admitted with a TBI secondary to a MVC. There were no significant demographic differences between patients admitted before or after 2009 (Age 39.67 vs 41.15 p = 0.086, Male 61.75% vs 64.07% p = 0.286, ISS 28.85 vs 28.87 p = 0.979, Brain AIS 3.76 vs 3.81 p = 0.119). While incidence of TBI from all causes increased by 15.59% since 2009, MVC as the mechanism of injury leading to hospital admission has declined by 4.70% (25.11% vs 20.41%, p < 0.0001). Severity of head injury also shifted with a reduction in the proportion of severe TBI (42.18% vs 37.09%, p = 0.0343) and an expansion of mild-moderate TBI (3.61% and 1.48% increase respectively). Early mortality (< 24 hrs of admission) decreased from 51.02% to 33.09% (p = 0.0034), while overall mortality was unchanged (Table 1).
Conclusion: Further work is needed to show a causal relationship, but since the widespread implementation of improved vehicle safety regulations there has been a significant reduction in severe TBI and proportionately higher rates of mild-moderate TBI after MVC. While overall mortality in this study was unchanged following 2009, those patients critically injured showed a significant improvement in early mortality.
