title: Use of Historical Surgical Times to Predict Duration of Primary Aortic Valve Replacement.
abstract: OBJECTIVE
  To test whether a model using a historical average of a surgeon's surgical times for primary aortic valve replacements is a more accurate predictor of actual surgical times than solely relying on a surgeon's estimate.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Single university hospital that serves as a tertiary referral center.
  
  
  METHODS
  All patients undergoing primary aortic valve replacement between October 2008 and September 2014.
  
  
  METHODS
  None.
  
  
  RESULTS
  Estimation biases, calculated as the difference between actual and predicted surgical time, were compared between the surgeon and the model, which included between 2 and 20 cases in the historical average. Kruskal-Wallis analysis of variance was used to compare all values. Pairwise comparisons were made using the Steel-Dwass test to determine whether using more cases in the model resulted in smaller estimation biases. Using the historical model reduced mean overestimation bias from 55.30 minutes to 0.90-to-4.67 minutes. No significant difference was seen based on the number of cases used.
  
  
  CONCLUSIONS
  An uncomplicated model can assist in providing comparatively unbiased estimations of surgical time for aortic valve replacements. The model can rely on a fewer number of cases (eg, 5) and does not benefit from including more cases (eg, 20).
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Albert
authors.initials: A
authors.lastname: Wu
authors.affiliation: Division of Cardiac Surgery, Brigham and Women's Hospital, Boston, MA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Rinewalt
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Lekowski
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA; Center for Perioperative Research, Brigham and Women's Hospital, Boston, MA. Electronic address: rurman@partners.org.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Urman
mesh_terms: D001024:Aortic Valve Stenosis / Q000453:epidemiology / Q000601:surgery*; D005544:Forecasting; D019918:Heart Valve Prosthesis Implantation / Q000379:methods / Q000639:trends*; D006801:Humans; D008962:Models, Theoretical; D061646:Operative Time; D012189:Retrospective Studies; D066231:Surgeons / Q000639:trends*; D062606:Tertiary Care Centers / Q000639:trends*
keywords: OR time; aortic valve replacement; estimation; prediction; scheduling; surgical time