title: Cardiac arrest diagnostic accuracy of 9-1-1 dispatchers: a prospective multi-center study.
abstract: BACKGROUND
  We sought to determine the ability of 9-1-1 dispatchers to accurately determine the presence of out-of-hospital cardiac arrest (OOHCA) over the telephone, and to determine the frequency with which CPR instructions are initiated and chest compressions delivered in patients not in cardiac arrest.
  
  
  METHODS
  We conducted a multi-center, prospective cohort study of adult OOHCA patients not witnessed by EMS for which resuscitation was attempted. Dispatchers were not health care professionals and received 6 weeks of training followed by a 6-month preceptorship. We reviewed 9-1-1 call digital recordings for all unconscious patients for which the possibility of cardiac arrest was considered using a piloted standardized data collection sheet.
  
  
  RESULTS
  We reviewed 2260 recordings occurring between January 2008 and October 2009. Among those, 1536 were confirmed OOHCA, and 724 were not. Among the 1536 confirmed OOHCA cases, 1012 were recognized by dispatchers and 524 were not. Among the 724 cases not in cardiac arrest, dispatchers suspected cardiac arrest was present in 490 and absent in 234. OOHCA diagnostic accuracy characteristics were: sensitivity 65.9% (95% CI 63.5-68.2%), specificity 32.3% (95% CI 29.0-35.9%), PPV 67.4%, and NPV 30.9%. Dispatchers believed that OOHCA was present in 490/2260 (21.7%) cases when it was not, resulting in 54/490 (11.0%) patients inappropriately receiving chest compressions, or 54/2260 (2.4%) of the whole cohort.
  
  
  CONCLUSIONS
  Dispatchers had a fair sensitivity and modest specificity for the recognition of OOHCA. We found a very small number of patients receiving CPR when not in cardiac arrest, supporting the current use of dispatch-assisted CPR instructions.
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, ON, Canada; Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada; Department of Epidemiology and Community Medicine, University of Ottawa, ON, Canada. Electronic address: cvaillancourt@ohri.ca.
authors.forename: Christian
authors.initials: C
authors.lastname: Vaillancourt
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Manya
authors.initials: M
authors.lastname: Charette
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Ann
authors.initials: A
authors.lastname: Kasaboski
authors.affiliation: Advanced Care Paramedic, Ottawa Paramedic Service, Ottawa, ON, Canada.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hoad
authors.affiliation: Ottawa Paramedic Service Central Ambulance Communication Center, Ottawa, ON, Canada.
authors.forename: Vivianne
authors.initials: V
authors.lastname: Larocque
authors.affiliation: Ottawa Paramedic Service Central Ambulance Communication Center, Ottawa, ON, Canada.
authors.forename: Denis
authors.initials: D
authors.lastname: Crête
authors.affiliation: Ottawa Paramedic Service Central Ambulance Communication Center, Ottawa, ON, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Logan
authors.affiliation: Ottawa Paramedic Service Central Ambulance Communication Center, Ottawa, ON, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lamoureux
authors.affiliation: Ottawa Paramedic Service Central Ambulance Communication Center, Ottawa, ON, Canada.
authors.forename: Jeff
authors.initials: J
authors.lastname: McBride
authors.affiliation: Sunnyrook Center for Prehospital Medicine, Department of Emergency Medicine, University of Toronto, ON, Canada.
authors.forename: Sheldon
authors.initials: S
authors.lastname: Cheskes
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada; Ottawa Heart Institute, Ottawa, ON, Canada; Department of Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, ON, Canada; Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada; Department of Epidemiology and Community Medicine, University of Ottawa, ON, Canada.
authors.forename: Ian G
authors.initials: IG
authors.lastname: Stiell
mesh_terms: D002170:Canada; D016887:Cardiopulmonary Resuscitation / Q000193:education / Q000706:statistics & numerical data; D004631:Emergency Medical Service Communication Systems; D006801:Humans; D058687:Out-of-Hospital Cardiac Arrest / Q000175:diagnosis* / Q000628:therapy; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
keywords: 9-1-1 dispatchers; CPR instructions; Cardiac arrest; Chest compressions; Dispatch-assisted CPR