title: Application of an evidence-based decision rule to patients with suspected pulmonary embolism.
abstract: BACKGROUND
  To support doctors in diagnosing patients who are suspected to have pulmonary embolism, the Christopher evidence-based decision rule was implemented in hospitals in the Netherlands. This study examines whether the Christopher evidence-based decision rule is applied in clinical practice. In addition, doctors' considerations for not applying the decision rule are explored.
  
  
  METHODS
  Dyspnoea patients were included in the study prospectively. The diagnostic process of the patients with suspected pulmonary embolism, as judged by the treating doctor, was compared with the Christopher evidence-based decision rule using patient record reviews. In addition, 14 interviews were conducted with doctors who did not follow the Christopher evidence-based decision rule to obtain insights into their considerations.
  
  
  RESULTS
  In 80 of 247 dyspnoea cases, the treating doctors suspected pulmonary embolism. The Christopher evidence-based decision rule was applied in 17 out of 80 cases. In 22 cases, more tests were performed than was suggested by the decision rule [i.e. computer-assisted tomographic angiography (CTa) or D-dimer], while in 41 cases fewer tests were performed than suggested by the decision rule. Considerations for not following the decision rule included judging another diagnosis to be more likely and not wanting to expose the patient to CTa radiation.
  
  
  CONCLUSIONS
  The Christopher evidence-based decision rule for diagnosing pulmonary embolism was not always followed in everyday clinical practice. Doctors seem to base their diagnostic strategy on their own estimate of the likelihood of pulmonary embolism, rather than the whole decision rule. Better adherence to the decision rule could be beneficial by making doctors aware that pulmonary embolism is more likely than they initially thought. However, in a substantial number of cases, it seemed justifiable that doctors deviated from the decision rule. Therefore, further research is needed to determine the value of the Christopher evidence-based decision rule in clinical practice.
authors.affiliation: Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands. laura.zwaan@vumc.nl
authors.forename: Laura
authors.initials: L
authors.lastname: Zwaan
authors.forename: Abel
authors.initials: A
authors.lastname: Thijs
authors.forename: Cordula
authors.initials: C
authors.lastname: Wagner
authors.forename: Daniëlle R M
authors.initials: DR
authors.lastname: Timmermans
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003657:Decision Making; D003937:Diagnosis, Differential; D004417:Dyspnea / Q000175:diagnosis; D055317:Evidence-Based Practice; D005260:Female; D006339:Heart Rate; D006469:Hemoptysis / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000453:epidemiology
keywords: clinical decision rules; diagnosis; dyspnoea; evidence-based medicine; medical-decision making; pulmonary embolism