title: Simulating changes to emergency care resources to compare system effectiveness.
abstract: OBJECTIVE
  To apply systems optimization methods to simulate and compare the most effective locations for emergency care resources as measured by access to care.
  
  
  METHODS
  This study was an optimization analysis of the locations of trauma centers (TCs), helicopter depots (HDs), and severely injured patients in need of time-critical care in select US states. Access was defined as the percentage of injured patients who could reach a level I/II TC within 45 or 60 minutes. Optimal locations were determined by a search algorithm that considered all candidate sites within a set of existing hospitals and airports in finding the best solutions that maximized access.
  
  
  RESULTS
  Across a dozen states, existing access to TCs within 60 minutes ranged from 31.1% to 95.6%, with a mean of 71.5%. Access increased from 0.8% to 35.0% after optimal addition of one or two TCs. Access increased from 1.0% to 15.3% after optimal addition of one or two HDs. Relocation of TCs and HDs (optimal removal followed by optimal addition) produced similar results.
  
  
  CONCLUSIONS
  Optimal changes to TCs produced greater increases in access to care than optimal changes to HDs although these results varied across states. Systems optimization methods can be used to compare the impacts of different resource configurations and their possible effects on access to care. These methods to determine optimal resource allocation can be applied to many domains, including comparative effectiveness and patient-centered outcomes research.
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, 423 Guardian Drive, Philadelphia, PA 19104, USA. cbranas@upenn.edu
authors.forename: Charles C
authors.initials: CC
authors.lastname: Branas
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Wolff
authors.forename: Justin
authors.initials: J
authors.lastname: Williams
authors.forename: Gregg
authors.initials: G
authors.lastname: Margolis
authors.forename: Brendan G
authors.initials: BG
authors.lastname: Carr
mesh_terms: D000465:Algorithms; D000552:Ambulances / Q000458:organization & administration*; D057186:Comparative Effectiveness Research; D003198:Computer Simulation; D004632:Emergency Medical Services / Q000458:organization & administration*; D005843:Geography; D015276:Health Care Rationing / Q000379:methods*; D006291:Health Policy; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand; D006801:Humans; D017146:Models, Organizational; D009874:Operations Research; D062206:Spatial Analysis; D013997:Time Factors; D014193:Trauma Centers / Q000458:organization & administration; D014481:United States; D014947:Wounds and Injuries / Q000628:therapy
keywords: Access to care; Geography; Health policy; Health system optimization; Location science; Trauma center; Wound and injuries