title: Reduced mortality in injured adults transported by helicopter emergency medical services.
abstract: BACKGROUND
  Some studies have shown improved outcomes with helicopter emergency medical services (HEMS) transport, while others have not. Safety concerns and cost have prompted reevaluation of the widespread use of HEMS.
  
  
  OBJECTIVE
  To determine whether the mode of transport of trauma patients affects mortality.
  
  
  METHODS
  Data for 56,744 injured adults aged ≥ 18 years transported to 62 U.S. trauma centers by helicopter or ground ambulance were obtained from the National Sample Program of the 2007 National Trauma Data Bank. In-hospital mortality was calculated for different demographic and injury severity groups. Adjusted odds ratios (AOR) were produced by utilizing a logistic regression model measuring the association of mortality and type of transport, controlling for age, gender, and injury severity (Injury Severity Score [ISS] and Revised Trauma Score [RTS]).
  
  
  RESULTS
  The odds of death were 39% lower in those transported by HEMS compared with those transported by ground ambulance (AOR = 0.61, 95% confidence interval [CI] = 0.54-0.69). Among those aged ≥ 55 years, the odds of death were not significantly different (AOR = 0.92, 95% CI = 0.74-1.13). Among all transports, male patients had a higher odds of death (AOR = 1.23, 95% CI = 1.10-1.38) than female patients. The odds of death increased with each year of age (AOR = 1.040, 95% CI = 1.037-1.043) and each unit of ISS (AOR = 1.080, 95% CI = 1.075-1.084), and decreased with each unit of RTS (AOR = 0.46, 95% CI = 0.45-0.48).
  
  
  CONCLUSIONS
  The use of HEMS for the transport of adult trauma patients was associated with reduced mortality for patients aged 18-54 years. In this study, HEMS did not improve mortality in adults aged ≥ 55 years. Identification of additional variables in the selection of those patients who will benefit from HEMS transport is expected to enhance this reduction in mortality.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, Atlanta, Georgia 30341, USA.
authors.forename: Ernest E
authors.initials: EE
authors.lastname: Sullivent
authors.forename: Mark
authors.initials: M
authors.lastname: Faul
authors.forename: Marlena M
authors.initials: MM
authors.lastname: Wald
mesh_terms: D000293:Adolescent; D000328:Adult; D017732:Air Ambulances / Q000706:statistics & numerical data; D000401:Aircraft / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D004636:Emergency Service, Hospital / Q000458:organization & administration / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010360:Patient Transfer / Q000379:methods / Q000706:statistics & numerical data*; D014193:Trauma Centers / Q000706:statistics & numerical data; D015599:Trauma Severity Indices; D014481:United States; D055815:Young Adult