Real-time sample entropy predicts life-saving interventions after the Boston Marathon bombing

J Crit Care. 2013 Dec;28(6):1109.e1-4. doi: 10.1016/j.jcrc.2013.08.026. Epub 2013 Oct 10.


Purpose: 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.

Materials and 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.

Keywords: Bleeding; Bombing; Entropy; Trauma.

MeSH terms

  • Adult
  • Blast Injuries / physiopathology*
  • Blast Injuries / therapy*
  • Boston
  • Entropy
  • Female
  • Heart Rate / physiology*
  • Humans
  • Injury Severity Score
  • Length of Stay / statistics & numerical data
  • Male
  • Prospective Studies
  • Treatment Outcome
  • Triage / methods*