title: The value of the difference between ED and prehospital vital signs in predicting outcome in trauma.
abstract: BACKGROUND
  Traditional vital signs are seen as an important part of trauma assessment, despite their poor predictive value in this regard.
  
  
  OBJECTIVE
  This study evaluated whether the difference between systolic blood pressure (SBP), heart rate (HR), respiratory rate (RR) and shock index (SI) taken in the emergency department (ED) and prehospital can predict 48 h mortality postadmission following trauma.
  
  
  METHODS
  Retrospective cohort was obtained from the Trauma Audit and Research Network. Subjects were excluded if head or spinal injuries, prehospital intubation or CPR were present. Main outcome was 48 h mortality. The difference (delta, Δ) between ED and prehospital values were used as study variables (ie, ΔSI=SI-ED minus SI-prehospital). Accuracy was assessed using area under receiver operator characteristic curve (AUROC). AUROC coordinates were used to identify 95% specificity cut points and described further using sensitivity and likelihood ratios (LRs).
  
  
  RESULTS
  Significant AUROC statistics were revealed for ΔSBP (0.57) and ΔRR (0.56) for the full sample, ΔSBP (0.62) and ΔSI (0.65) for moderate, and ΔRR (0.6) for severe injury. Best LRs were 3.4 and 2.4 for ΔRR and ΔSI, respectively, but sensitivities were low (<=26%). Cut point values for ΔSBP, ΔRR and ΔSI were 37 mm Hg, 8 breaths/min and 0.2, respectively.
  
  
  CONCLUSIONS
  ΔSBP and ΔRR performed best overall, but ΔSI performed best in the moderate injury group, suggesting earlier identification with ΔSI. Use of Δ values result in good rule-in of 48 h mortality and may supplement trauma treatment decisions.
authors.affiliation: Division of Emergency Medicine, University of Cape Town, Karl Bremer Hospital, Mike Pienaar Blvd, Bellville, South Africa.|Emergency Department, Derriford Hospital, Plymouth Hospitals NHS Trust, Plymouth, UK.
authors.forename: Stevan R
authors.initials: SR
authors.lastname: Bruijns
authors.affiliation: Emergency Department, Derriford Hospital, Plymouth Hospitals NHS Trust, Plymouth, UK.
authors.forename: Henry R
authors.initials: HR
authors.lastname: Guly
authors.affiliation: Trauma Audit and Research Network, Health Sciences Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Salford Royal Hospital, Salford, UK.
authors.forename: Omar
authors.initials: O
authors.lastname: Bouamra
authors.affiliation: Emergency Department, Derriford Hospital, Plymouth Hospitals NHS Trust, Plymouth, UK.|Emergency Medicine Research in Sheffield (EMRiS), Health Services Research, School of Health and Related Research, University of Sheffield, Regent's Court, Salford, UK.
authors.forename: Fiona
authors.initials: F
authors.lastname: Lecky
authors.affiliation: Division of Emergency Medicine, University of Cape Town, Karl Bremer Hospital, Mike Pienaar Blvd, Bellville, South Africa.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Wallis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004632:Emergency Medical Services; D004636:Emergency Service, Hospital; D004739:England; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055986:Vital Signs; D014852:Wales; D014947:Wounds and Injuries / Q000401:mortality*
keywords: Trauma, research; assessment; basic ambulance care; resuscitation