title: The role of reduced heart rate volatility in predicting disposition from the emergency department.
abstract: OBJECTIVE
  Heart rate volatility (HRVO) is a physiological parameter that is believed to reflect the sympathetic activity of the autonomic nervous system. We explored the utility of HRVO as a predictive tool for declining physiological states, hypothesising that patients admitted from the resuscitation area of the ED to a high-dependency unit (HDU) experience low HRVO compared with patients who did not.
  
  
  METHODS
  We retrospectively reviewed HR data recordings, medical charts and disposition decisions from the ED of patients who were admitted to the five resuscitation beds in our adult ED between 29 April 2014 and 30 May 2015. HRVO was calculated for each 5 min interval; it was measured as the SD of all HRs within that interval. Logistic regression was used to model the odds of admission to a HDU given low HRVO during ED stay.
  
  
  RESULTS
  HR data from 2051 patients was collected and approximately 7 million HR data points were analysed. 402 patients experienced low HRVO. Patients who experienced low HRVO during their ED stay were twice as likely to be admitted to a HDU from the ED (OR=2.07, 95% CI 1.64 to 2.60; p<0.001).
  
  
  CONCLUSIONS
  Our result provides additional evidence supporting previously published data indicating that autonomic nervous system measures such as HRVO could serve as important and useful clinical tools in the early triage of critically ill patients in the ED.
authors.affiliation: Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Ya-El
authors.identifier: http://orcid.org/0000-0001-6937-2484
authors.initials: YE
authors.lastname: Mandel-Portnoy
authors.affiliation: Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.|Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: George T
authors.initials: GT
authors.lastname: Loo
authors.affiliation: Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Diana
authors.initials: D
authors.lastname: Gregoriou
authors.affiliation: Department of Cardiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Sameer
authors.initials: S
authors.lastname: Bansilal
authors.affiliation: Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.|Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Lynne D
authors.initials: LD
authors.lastname: Richardson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001341:Autonomic Nervous System / Q000503:physiopathology*; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000458:organization & administration / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends*; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000706:statistics & numerical data / Q000639:trends*; D012189:Retrospective Studies
keywords: cardiac care; emergency care systems, emergency departments; intensive care