title: Is it time to refine? An exploration and simulation of optimal antibiotic timing in general surgery.
abstract: BACKGROUND
  Postoperative infections increase morbidity, resource use, and costs. Our objective was to examine whether within guideline recommendations an optimal time exists for an initial dose of antibiotic to reduce postoperative infections in general surgery, and to simulate the magnitude of a reduction in infections should an optimal time be implemented.
  
  
  METHODS
  The population consisted of 6,731 patients who underwent 7,095 general surgery procedures between January 5, 2006 and June 25, 2012. Patients with pre-existing infections, such as pneumonia and sepsis, and patients with no recorded use of antibiotics were excluded, as were patients on vancomycin and surgical procedures longer than 4 hours in duration. The final analysis dataset included 4,453 patients. The National Surgical Quality Improvement Program was used for perioperative variables and outcomes. The end point was a composite of wound disruption; superficial, deep, organ space, surgical site infections; and sepsis. Semi-parametric logistic regression was used to study the association between antibiotic timing and infection.
  
  
  RESULTS
  There were 444 (10%) patients with a primary end point of infectious complication. A nonlinear "bowl-shaped" relationship between duration of interval from antibiotic administration and surgical incision and infection was observed; lowest risk corresponding to administration time close to incision was 4 minutes before incision (95% one-sided CI, 0-18 minutes). The model suggested optimal timing would result in an 11.3% reduction in the primary infection end point.
  
  
  CONCLUSIONS
  Risk of infectious complications decreased as antibiotic administration moved closer to incision time. These data suggest an opportunity to reduce infections by 11.3% by targeting initial antibiotic administration closer to incision.
authors.affiliation: Department of Cardiothoracic Anesthesia, Cleveland Clinic, Cleveland, OH; Quality and Patient Safety Institute, Cleveland Clinic, Cleveland, OH. Electronic address: kochc@ccf.org.
authors.forename: Colleen G
authors.initials: CG
authors.lastname: Koch
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Eric
authors.initials: E
authors.lastname: Hixson
authors.forename: Anne
authors.initials: A
authors.lastname: Tang
authors.forename: Steve
authors.initials: S
authors.lastname: Gordon
authors.forename: David
authors.initials: D
authors.lastname: Longworth
authors.forename: Shannon
authors.initials: S
authors.lastname: Phillips
authors.forename: Eugene
authors.initials: E
authors.lastname: Blackstone
authors.forename: J Michael
authors.initials: JM
authors.lastname: Henderson
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis; D015331:Cohort Studies; D004334:Drug Administration Schedule; D005260:Female; D013502:General Surgery; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D013530:Surgical Wound Infection / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000900:Anti-Bacterial Agents