title: Does the use of dedicated dispatch criteria by Emergency Medical Services optimise appropriate allocation of advanced care resources in cases of high severity trauma? A systematic review.
abstract: OBJECTIVE
  The deployment of Enhanced Care Teams (ECTs) capable of delivering advanced clinical interventions for patients at the scene of incidents is commonplace by Emergency Medical Services in most developed countries. It is unclear whether primary dispatch models for ECT resources are more efficient at targeting deployment to patients with severe trauma than secondary dispatch, following requests from EMS personnel at scene. The objective of this study was to review the evidence for primary and secondary models in the targeted dispatch of ECT resources to patients with severe traumatic injury.
  
  
  METHODS
  This review was completed in accordance with a protocol developed using the PRISMA guidelines. We conducted a search of the MEDLINE, EmBase, Web of Knowledge/Science databases and the Cochrane library, focussed on subject headings and keywords involving the dispatch of ECT resources by Emergency Medical Services. Design and results of each study were described. Heterogeneity in the design of the included studies precluded the completion of a meta-analysis. A narrative synthesis of the results therefore was performed.
  
  
  RESULTS
  Five hundred and forty-eight articles were screened, and 16 were included. Only one study compared the performance of the different models of dispatch. A non-statistically significant reduction in the length of time for HEMS resources to reach incident scenes of 4min was found when primary dispatch protocols were utilised compared to requests from EMS personnel at scene. No effect on mortality; severity of injury or proportion of patients admitted to intensive care was observed. The remaining studies examined the processes utilised within current primary dispatch models but did not perform any comparative analysis with existing secondary dispatch models.
  
  
  CONCLUSIONS
  This review identifies a lack of evidence supporting the role of primary dispatch models in targeting the deployment of Enhanced Care Teams to patients with severe injuries. It is therefore not possible to identify a model for ECT dispatch within pre-hospital systems that optimises resource utilisation. Further studies are required to assess the efficiency of systems utilised at each stage of the process used to dispatch Enhanced Care Team resources to incidents within regionalised pre-hospital trauma systems.
authors: Clinical Trials Unit, University of Warwick Gibbet Hill, CV4 7AL Coventry, UK. Electronic address: carl_mcqueen@hotmail.com.
authors: Carl
authors: C
authors: McQueen
authors: Clinical Trials Unit, University of Warwick Gibbet Hill, CV4 7AL Coventry, UK. Electronic address: m.a.smyth@warwick.ac.uk.
authors: Mike
authors: M
authors: Smyth
authors: University of Warwick, Gibbet Hill, CV4 7AL Coventry, UK. Electronic address: joanne.fisher@warwick.ac.uk.
authors: Joanne
authors: J
authors: Fisher
authors: Clinical Trials Unit, University of Warwick Gibbet Hill, CV4 7AL Coventry, UK. Electronic address: g.d.perkins@warwick.ac.uk.
authors: Gavin
authors: G
authors: Perkins
mesh_terms: D017732:Air Ambulances / Q000706:statistics & numerical data; D002985:Clinical Protocols; D004632:Emergency Medical Services / Q000379:methods / Q000458:organization & administration*; D019983:Guideline Adherence; D017408:Guidelines as Topic; D006801:Humans; D015601:Injury Severity Score; D008020:Life Support Care; D009104:Multiple Trauma; D061665:Time-to-Treatment / Q000706:statistics & numerical data*; D014218:Triage; D014947:Wounds and Injuries / Q000628:therapy*
keywords: Dispatch; Emergency Medical Services; Enhanced Care Teams; Major Trauma