title: Occupant- and collision-related risk factors for blunt thoracic aorta injury.
abstract: BACKGROUND
  Blunt thoracic aortic injury (BAI) is a rare and highly lethal injury. We sought to identify occupant and collision characteristics associated with motor vehicle collision (MVC)-related BAI.
  
  
  METHODS
  The 1995 to 2000 National Automotive Sampling System data files were used. The National Automotive Sampling System is a national probability sample of passenger vehicles involved in police-reported tow-away MVCs. The risk of BAI was calculated according to specific occupant (e.g., age, seat belt use) and collision (e.g., delta-V [estimated change in velocity], vehicular intrusion) characteristics. The association between BAI and these characteristics was calculated using risk ratios (RRs) and associated 95% confidence intervals (CIs).
  
  
  RESULTS
  Specific occupant and collision characteristics demonstrated independent association with BAI. Occupant characteristics included age >or= 60 (RR, 3.6; 95% CI, 2.5-5.2), seat belt use (RR, 0.3; 95% CI, 0.2-0.5), and being a front-seat occupant (RR, 3.1; 95% CI, 1.5-6.3). Frontal and near-side MVCs were associated with an increased risk (RR, 3.1; 95% CI, 1.9-5.1; and RR, 4.3; 95% CI, 2.6-7.2, respectively) relative to other collision types. Collisions with a delta-V >or= 40 km/h (RR, 3.8; 95% CI, 2.6-5.6) or that produce extensive vehicle crush (>or= 40 cm) (RR, 4.1; 95% CI, 2.7-6.3) or intrusion (>or= 15 cm) (RR, 5.0; 95% CI, 3.5-7.3) also increase the risk of BAI.
  
  
  CONCLUSIONS
  The risk factors for BAI identified in this study support generally accepted etiologic mechanisms for this injury.
authors.affiliation: Department of Surgery, School of Medicine, Center for Injury Sciences, University of Alabama at Birmingham, 35294-0016, USA. gerald.mcgwin@ccc.uab.edu
authors.forename: Gerald
authors.initials: G
authors.lastname: McGwin
authors.forename: Jesse
authors.initials: J
authors.lastname: Metzger
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Moran
authors.forename: Loring W
authors.initials: LW
authors.lastname: Rue
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001013:Aorta, Thoracic / Q000293:injuries*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014949:Wounds, Nonpenetrating / Q000453:epidemiology / Q000209:etiology*