title: Derivation of a termination-of-resuscitation guideline for emergency medical technicians using automated external defibrillators.
abstract: OBJECTIVE
  To determine the association between characteristics of cardiac arrest and survival to hospital discharge following failed resuscitation by defibrillation-trained emergency medical technicians (EMT-Ds), and to propose an out-of-hospital termination-of-resuscitation (TOR) guideline for EMT-Ds.
  
  
  METHODS
  A 22-month retrospective review of 700 out-of-hospital primary cardiac arrest patients in a large emergency medical services (EMS) system who received exclusively EMT-D care.
  
  
  RESULTS
  Seven hundred primary cardiac arrest patients were identified. Follow-up was obtained in 662 cases (94.6%). Of these, 36 (5.4%) achieved a return of spontaneous circulation (ROSC) prior to transport. Among the 626 patients who failed to achieve ROSC at any time, two (0.3%) survived to discharge. Multivariate analysis showed that ROSC at any time had the strongest association with survival [odds ratio (OR) 45.5; 95% confidence interval (95% CI) = 8.5 to 243.7]. A shock prior to transport (OR 6.9; 95% CI = 1.2 to 40.3) and cardiac arrest witnessed by EMS personnel (OR 4.4; 95% CI = 1.0 to 18.5) were also independently associated with survival. These variables were incorporated into a TOR guideline. The guideline was 100% sensitive (95% CI = 99.1 to 100) in identifying survivors and had 100% negative predictive value (95% CI = 75.3 to 100) for identifying nonsurvivors of out-of-hospital cardiac arrest in the study population.
  
  
  CONCLUSIONS
  In this EMS system, cardiac arrest patients may be considered for out-of-hospital TOR following EMT-D resuscitation attempts when there has been no ROSC, no shock has been given, and the arrest was not witnessed by EMS personnel. These guidelines require prospective validation.
authors.affiliation: Division of Prehospital Care, Department of Emergency Services, Sunnybrook & Women's College Health Sciences Centre, Toronto, Ontario, Canada. rverbeek@basehospital.on.ca
authors.forename: P Richard
authors.initials: PR
authors.lastname: Verbeek
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Vermeulen
authors.forename: Fahim H
authors.initials: FH
authors.lastname: Ali
authors.forename: David W
authors.initials: DW
authors.lastname: Messenger
authors.forename: Jim
authors.initials: J
authors.lastname: Summers
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Morrison
mesh_terms: D022561:Advanced Cardiac Life Support / Q000592:standards*; D000368:Aged; D000369:Aged, 80 and over; D004554:Electric Countershock / Q000592:standards*; D004632:Emergency Medical Services / Q000592:standards*; D004634:Emergency Medical Technicians / Q000592:standards*; D005260:Female; D006323:Heart Arrest / Q000628:therapy; D006801:Humans; D008297:Male; D017410:Practice Guidelines as Topic / Q000592:standards*; D016414:Resuscitation Orders; D012189:Retrospective Studies; D016019:Survival Analysis; D017211:Treatment Failure