title: Inaccurate treatment decisions of automated external defibrillators used by emergency medical services personnel: incidence, cause and impact on outcome.
abstract: BACKGROUND
  The rhythm analysis algorithm (RAA) of automated external defibrillators (AEDs) may be deceived by many factors. In this observational study we assessed RAA accuracy in prehospital interventions. For every rhythm analysis judged to be inaccurate, we looked for causal factors and estimated the impact on outcome.
  
  
  METHODS
  In 135 consecutive patients, two physicians reviewed 837 rhythm analyses independently. When they disagreed, a third physician made the final decision.
  
  
  RESULTS
  Among 148 shockable episodes, 23 (16%) were not recognized by the RAA due to external artifacts (n=7), fine ventricular fibrillation (VF; n=7), RAA error without external artifacts (n=4) or a combination of factors (n=5). In six cases the omitted/delayed shock was judged to be of clinical relevance: survival with some neurological deficit (n=4), death without regaining consciousness (n=1) and no restoration of spontaneous circulation (n=1). In 689 non-shockable episodes, the RAA decided "shockable" 25 times (4%). This wrongful decision was due to external artifacts (n=9), a concurrent shock of an internal cardioverter defibrillator (n=1), RAA error without external artifacts (n=13) or a combination of factors (n=2). Fifteen spurious shocks were delivered. As these non-shockable rhythms did not deteriorate after the shock, we assumed that no significant harm was done.
  
  
  CONCLUSIONS
  Up to 16% of shockable rhythms were not detected and 4% of non-shockable rhythms were interpreted as shockable. Therefore, all AED interventions should be reviewed. Feedback to caregivers may avoid future deleterious interactions with the AED, whereas AED manufacturers may use this information to improve RAA accuracy. This approach may improve the outcome of some VF patients.
authors.affiliation: Ghent University, De Pintelaan 185, 9000 Ghent, Belgium; Department of Emergency Medicine, Maria Middelares General Hospital, Kortrijksesteenweg 1026, 9000 Ghent, Belgium. Electronic address: paul.calle@ugent.be.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Calle
authors.affiliation: Ghent University, De Pintelaan 185, 9000 Ghent, Belgium; Department of Emergency Medicine, Ghent Sint Lucas General Hospital, Groene Briel 1, 9000 Ghent, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mpotos
authors.affiliation: Ghent University, De Pintelaan 185, 9000 Ghent, Belgium.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Calle
authors.affiliation: Ghent University, De Pintelaan 185, 9000 Ghent, Belgium; Department of Emergency Medicine, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Koenraad G
authors.initials: KG
authors.lastname: Monsieurs
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001530:Belgium / Q000453:epidemiology; D016887:Cardiopulmonary Resuscitation; D003657:Decision Making; D047548:Defibrillators; D004562:Electrocardiography; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D006801:Humans; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D014693:Ventricular Fibrillation / Q000628:therapy*
keywords: Automated external defibrillators; Outcome; Quality assurance