title: Timing of elective surgery as a perioperative outcome variable: analysis of pancreaticoduodenectomy.
abstract: OBJECTIVE
  The timing of major elective operations is a potentially important but rarely examined outcome variable. This study examined elective pancreaticoduodenectomy (PD) timing as a perioperative outcome variable.
  
  
  METHODS
  Consecutive patients submitted to PD were identified. Determinants of 90-day morbidity (prospectively graded and tracked), anastomotic leak or fistula, and mortality, including operation start time (time of day), day of week and month, were assessed in univariate and multivariate analyses. Operation start time was analysed as a continuous and a categorical variable.
  
  
  RESULTS
  Of the 819 patients identified, 405 (49.5%) experienced one or more complications (total number of events = 684); 90-day mortality was 3.5%. On multivariate analysis, predictors of any morbidity included male gender (P = 0.009) and estimated blood loss (P = 0.017). Male gender (P = 0.002), benign diagnosis (P = 0.002), presence of comorbidities (P = 0.002), American Society of Anesthesiologists (ASA) score (P = 0.025), larger tumour size (P = 0.013) and positive resection margin status (P = 0.005) were associated with the occurrence of anastomotic leak or fistula. Cardiac and pulmonary comorbidities were the only variables associated with 90-day mortality. Variables pertaining to procedure scheduling were not associated with perioperative morbidity or mortality. Operation start time was not significant when analysed as a continuous or a categorical variable, or when stratified by surgeon.
  
  
  CONCLUSIONS
  Perioperative outcome after PD is determined by patient, disease and operative factors and does not appear to be influenced by procedure timing.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Raphael L C
authors.initials: RL
authors.lastname: Araujo
authors.forename: Ami M
authors.initials: AM
authors.lastname: Karkar
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Allen
authors.forename: Mithat
authors.initials: M
authors.lastname: Gönen
authors.forename: Joanne F
authors.initials: JF
authors.lastname: Chou
authors.forename: Murray F
authors.initials: MF
authors.lastname: Brennan
authors.forename: Leslie H
authors.initials: LH
authors.lastname: Blumgart
authors.forename: Michael I
authors.initials: MI
authors.lastname: D'Angelica
authors.forename: Ronald P
authors.initials: RP
authors.lastname: DeMatteo
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Coit
authors.forename: Yuman
authors.initials: Y
authors.lastname: Fong
authors.forename: William R
authors.initials: WR
authors.lastname: Jarnagin
mesh_terms: D000328:Adult; D039602:After-Hours Care; D000368:Aged; D000369:Aged, 80 and over; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D016577:Pancreaticoduodenectomy / Q000009:adverse effects / Q000401:mortality; D010561:Personnel Staffing and Scheduling; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome; D016526:Workload