title: Real-time sample entropy predicts life-saving interventions after the Boston Marathon bombing.
abstract: OBJECTIVE
  Identifying patients in need of a life-saving intervention (LSI) during a mass casualty event is a priority. We hypothesized that real-time, instantaneous sample entropy (SampEn) could predict the need for LSI in the Boston Marathon bombing victims.
  
  
  METHODS
  Severely injured Boston Marathon bombing victims (n = 10) had sample entropy (SampEn) recorded upon presentation using a continuous 200-beat rolling average in real time. Treating clinicians were blinded to real-time results. The correlation between SampEn, injury severity, number, and type of LSI was examined.
  
  
  RESULTS
  Victims were males (60%) with a mean age of 39.1 years. Injuries involved lower extremities (50.0%), head and neck (24.2%), or upper extremities (9.7%). Sample entropy negatively correlated with Injury Severity Score (r = -0.70; P = .023), number of injuries (r = -0.70; P = .026), and the number and need for LSI (r = -0.82; P = .004). Sample entropy was reduced under a variety of conditions. (Table see text).
  
  
  CONCLUSIONS
  Sample entropy strongly correlates with injury severity and predicts LSI after blast injuries sustained in the Boston Marathon bombings. Sample entropy may be a useful triage tool after blast injury.
authors.affiliation: Department of Surgery, Division of Trauma, Emergency Surgery and Surgical Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Miroslav P
authors.initials: MP
authors.lastname: Peev
authors.forename: Leily
authors.initials: L
authors.lastname: Naraghi
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.forename: Marc
authors.initials: M
authors.lastname: Demoya
authors.forename: Peter
authors.initials: P
authors.lastname: Fagenholz
authors.forename: Daniel
authors.initials: D
authors.lastname: Yeh
authors.forename: George
authors.initials: G
authors.lastname: Velmahos
authors.forename: David R
authors.initials: DR
authors.lastname: King
mesh_terms: D000328:Adult; D001753:Blast Injuries / Q000503:physiopathology* / Q000628:therapy*; D001900:Boston; D019277:Entropy; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D015601:Injury Severity Score; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome; D014218:Triage / Q000379:methods*
keywords: Bleeding; Bombing; Entropy; Trauma