title: Prehospital helicopter transport and survival of patients with traumatic brain injury.
abstract: OBJECTIVE
  To investigate the association of helicopter transport with survival of patients with traumatic brain injury (TBI), in comparison with ground emergency medical services (EMS).
  
  
  BACKGROUND
  Helicopter utilization and its effect on the outcomes of TBI remain controversial.
  
  
  METHODS
  We performed a retrospective cohort study involving patients with TBI who were registered in the National Trauma Data Bank between 2009 and 2011. Regression techniques with propensity score matching were used to investigate the association of helicopter transport with survival of patients with TBI, in comparison with ground EMS.
  
  
  RESULTS
  During the study period, there were 209,529 patients with TBI who were registered in the National Trauma Data Bank and met the inclusion criteria. Of these patients, 35,334 were transported via helicopters and 174,195 via ground EMS. For patients transported to level I trauma centers, 2797 deaths (12%) were recorded after helicopter transport and 8161 (7.8%) after ground EMS. Multivariable logistic regression analysis demonstrated an association of helicopter transport with increased survival [OR (odds ratio), 1.95; 95% confidence interval (CI), 1.81-2.10; absolute risk reduction (ARR), 6.37%]. This persisted after propensity score matching (OR, 1.88; 95% CI, 1.74-2.03; ARR, 5.93%). For patients transported to level II trauma centers, 1282 deaths (10.6%) were recorded after helicopter transport and 5097 (7.3%) after ground EMS. Multivariable logistic regression analysis demonstrated an association of helicopter transport with increased survival (OR, 1.81; 95% CI, 1.64-2.00; ARR 5.17%). This again persisted after propensity score matching (OR, 1.73; 95% CI, 1.55-1.94; ARR, 4.69).
  
  
  CONCLUSIONS
  Helicopter transport of patients with TBI to level I and II trauma centers was associated with improved survival, in comparison with ground EMS.
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: Kimon
authors.initials: K
authors.lastname: Bekelis
authors.affiliation: Department of Neurosurgery, Cleveland Clinic, Cleveland, OH.
authors.forename: Symeon
authors.initials: S
authors.lastname: Missios
authors.affiliation: Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH.|Department of Community and Family Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH.|The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Mackenzie
mesh_terms: D017732:Air Ambulances; D000401:Aircraft; D001930:Brain Injuries / Q000401:mortality*; D004632:Emergency Medical Services / Q000458:organization & administration*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D057216:Propensity Score; D012307:Risk Factors; D016019:Survival Analysis; D014193:Trauma Centers; D014481:United States / Q000453:epidemiology
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