title: External Validation of the Universal Termination of Resuscitation Rule for Out-of-Hospital Cardiac Arrest in British Columbia.
abstract: OBJECTIVE
  The Universal Termination of Resuscitation Rule (TOR Rule) was developed to identify out-of-hospital cardiac arrests eligible for field termination of resuscitation, avoiding futile transportation to the hospital. The validity of the rule in emergency medical services (EMS) systems that do not routinely transport out-of-hospital cardiac arrest patients to the hospital is unknown. We seek to validate the TOR Rule in British Columbia.
  
  
  METHODS
  This study included consecutive, nontraumatic, adult, out-of-hospital cardiac arrests treated by EMS in British Columbia from April 2011 to September 2015. We excluded patients with active do-not-resuscitate orders and those with missing data. Following consensus guidelines, we examined the validity of the TOR Rule after 6 minutes of resuscitation (to approximate three 2-minute cycles of resuscitation). To ascertain rule performance at the different time junctures, we recalculated TOR Rule classification accuracy at subsequent 1-minute resuscitation increments.
  
  
  RESULTS
  Of 6,994 consecutive, adult, EMS-treated, out-of-hospital cardiac arrests, overall survival was 15%. At 6 minutes of resuscitation, rule performance was sensitivity 0.72, specificity 0.91, positive predictive value 0.98, and negative predictive value 0.36. The TOR Rule recommended care termination for 4,367 patients (62%); of these, 92 survived to hospital discharge (false-positive rate 2.1%; 95% confidence interval 1.7% to 2.5%); however, this proportion steadily decreased with later application. The TOR Rule recommended continuation of resuscitation in 2,627 patients (38%); of these, 1,674 died (false-negative rate 64%; 95% confidence interval 62% to 66%). Compared with 6-minute application, test characteristics at 30 minutes demonstrated nearly perfect positive predictive value (1.0) and specificity (1.0) but a lower sensitivity (0.46) and negative predictive value (0.25).
  
  
  CONCLUSIONS
  In this cohort of adult out-of-hospital cardiac arrest patients, the TOR Rule applied at 6 minutes falsely recommended care termination for 2.1% of patients; however, this decreased with later application. Systems using the TOR Rule to cease resuscitation in the field should consider rule application at points later than 6 minutes.
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada; Centre for Health Evaluation and Outcome Sciences, Vancouver, British Columbia, Canada. Electronic address: bgrunau@mail.ubc.ca.
authors.forename: Brian
authors.initials: B
authors.lastname: Grunau
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Taylor
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Frank X
authors.initials: FX
authors.lastname: Scheuermeyer
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada; Centre for Health Evaluation and Outcome Sciences, Vancouver, British Columbia, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Stenstrom
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; British Columbia Emergency Health Services.
authors.forename: William
authors.initials: W
authors.lastname: Dick
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada; Department of Emergency Medicine, University of Fukui Hospital, Fukui Prefecture, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kawano
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Barbic
authors.affiliation: Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Drennan
authors.affiliation: Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada; St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Jim
authors.initials: J
authors.lastname: Christenson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia; D016887:Cardiopulmonary Resuscitation / Q000941:ethics / Q000379:methods* / Q000401:mortality / Q000592:standards*; D003661:Decision Support Techniques; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D017410:Practice Guidelines as Topic / Q000592:standards*; D016414:Resuscitation Orders / Q000941:ethics; D015996:Survival Rate