title: Levels of evidence and grades of recommendations in general thoracic surgery.
abstract: OBJECTIVE
  To determine the grades of recommendations and levels of evidence available if the formal practice of evidence-based medicine is applied to general thoracic surgery.
  
  
  METHODS
  Three general thoracic surgeons, by consensus, developed a sample of 10 clinically important questions. The first 3 steps of evidence-based medicine (creation of answerable clinical questions, search for best external evidence, and critical appraisal of literature) were performed. Abstracts and appropriate articles were identified through Medline from January 1999 through December 2001. A hierarchical series of search strategies was employed to identify the best level of evidence. The best evidence found was categorized according to the Oxford Centre for Evidence-Based Medicine into 4 grades of recommendations (A-D) and 5 levels of evidence (1-5).
  
  
  RESULTS
  The best evidence found for the 10 sample questions was categorized as grade A recommendations in 5 and grade B, also in 5 questions. The levels of evidence found were la in 3 studies, 1b in 5, and 2b in 2.
  
  
  CONCLUSIONS
  A formal evidence-based-medicine approach to general thoracic surgery found the grades of recommendation and levels of evidence for a sample of clinically important questions to be high.
authors.affiliation: Division of Thoracic Surgery, University of Calgary, Calgary, Alta. andrew.graham@calgaryhealthregion.ca
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Graham
authors.forename: Gary
authors.initials: G
authors.lastname: Gelfand
authors.forename: Sean D
authors.initials: SD
authors.lastname: McFadden
authors.forename: Sean C
authors.initials: SC
authors.lastname: Grondin
mesh_terms: D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D011364:Professional Practice / Q000592:standards; D013903:Thoracic Surgery / Q000592:standards*