title: Assessing clinical probability of pulmonary embolism in the emergency ward: a simple score.
abstract: OBJECTIVE
  To develop a simple standardized clinical score to stratify emergency ward patients with clinically suspected pulmonary embolism (PE) into groups with a high, intermediate, or low probability of PE to improve and simplify the diagnostic approach.
  
  
  METHODS
  Analysis of a database of 1090 consecutive patients admitted to the emergency ward for suspected PE in whom diagnosis of PE was ruled in or out by a standard diagnostic algorithm. Logistic regression was used to predict clinical parameters associated with PE.
  
  
  RESULTS
  A total of 296 (27%) of 1090 patients were found to have PE. The optimal estimate of clinical probability was based on 8 variables: recent surgery, previous thromboembolic event, older age, hypocapnia, hypoxemia, tachycardia, band atelectasis, or elevation of a hemidiaphragm on chest x-ray film. A probability score was calculated by adding points assigned to these variables. A cutoff score of 4 best identified patients with low probability of PE. A total of 486 patients (49%) had a low clinical probability of PE (score </=4), of which 50 (10.3%) had a proven PE. The prevalence of PE was 38% in the 437 patients with an intermediate probability (score of 5-8; n = 437) and 81% in the 63 patients with a high probability (score >/=9).
  
  
  CONCLUSIONS
  This clinical score, based on easily available and objective variables, provides a standardized assessment of the clinical probability of PE. Applying this score to emergency ward patients suspected of having PE could allow a more effective diagnostic process.
authors.affiliation: Medical Clinic 1, Department of Internal Medicine, Geneva University Hospital, 24 Rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Wicki
authors.forename: T V
authors.initials: TV
authors.lastname: Perneger
authors.forename: A F
authors.initials: AF
authors.lastname: Junod
authors.forename: H
authors.initials: H
authors.lastname: Bounameaux
authors.forename: A
authors.initials: A
authors.lastname: Perrier
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019992:Databases as Topic; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012044:Regression Analysis