title: Heart rate variability as a triage tool in patients with trauma during prehospital helicopter transport.
abstract: BACKGROUND
  Prehospital triage of patients with trauma is routinely challenging, but more so in mass casualty situations and military operations. The purpose of this study was to prospectively test whether heart rate variability (HRV) could be used as a triage tool during helicopter transport of civilian patients with trauma.
  
  
  METHODS
  After institutional review board approval and waiver of informed consent, 75 patients with trauma requiring prehospital helicopter transport to our level I center (from December 2007 to November 2008) were prospectively instrumented with a 2-Channel SEER Light recorder (GE Healthcare, Milwaukee, WI). HRV was analyzed with a Mars Holter monitor system and proprietary software. SDNN (standard deviation [SD] of the normal-to-normal R-R interval), as an index of HRV, was correlated with prehospital trauma triage criteria, base deficit, seriousness of injury, operative interventions, outcome, and other data extracted from the patients' medical records. There were no interventions or medical decisions based on HRV. Data were excluded only if there was measurement artifact or technical problems with the recordings.
  
  
  RESULTS
  The demographics were mean age 47 years, 63% men, 88% blunt, 25% traumatic brain injury, 9% mortality. Prehospital SDNN predicted patients with base excess < or = -6, those defined as seriously injured and benefiting from trauma center care, as well as patients requiring a life-saving procedure in the operating room. No other available data, including prehospital en-route vital signs, predicted any of these. The sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 33%, 96%, respectively, with and an overall accuracy of 76% for predicting a life-saving intervention in the operating room.
  
  
  CONCLUSIONS
  This is the first demonstration that prehospital HRV (specifically SDNN) predicts base excess and operating room life-saving opportunities. HRV triages and discriminates severely injured patients better than routine trauma criteria or en-route prehospital vital signs. HRV may be a useful civilian or military triage tool to avoid unnecessary helicopter evacuation for minimally injured patients. A prospective, randomized trial in a larger patient population is indicated.
authors.affiliation: Division of Trauma, Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital andHarvard Medical School, 165 Cambridge Street, Suite 810, Boston, MA 02141, USA. Dking3@partners.org
authors.forename: David R
authors.initials: DR
authors.lastname: King
authors.forename: Michael P
authors.initials: MP
authors.lastname: Ogilvie
authors.forename: Bruno M T
authors.initials: BM
authors.lastname: Pereira
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Manning
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Conner
authors.forename: Carl I
authors.initials: CI
authors.lastname: Schulman
authors.forename: Mark G
authors.initials: MG
authors.lastname: McKenney
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Proctor
mesh_terms: D000328:Adult; D000368:Aged; D017732:Air Ambulances; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014218:Triage / Q000379:methods*; D014947:Wounds and Injuries / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy