title: Time of day effects on the incidence of anesthetic adverse events.
abstract: BACKGROUND
  We hypothesized that time of day of surgery would influence the incidence of anesthetic adverse events (AEs).
  
  
  METHODS
  Clinical observations reported in a quality improvement database were categorized into different AEs that reflected (1) error, (2) harm, and (3) other AEs (error or harm could not be determined) and were analyzed for effects related to start hour of care.
  
  
  RESULTS
  As expected, there were differences in the rate of AEs depending on start hour of care. Compared with a reference start hour of 7 am, other AEs were more frequent for cases starting during the 3 pm and 4 pm hours (p < 0.0001). Post hoc inspection of data revealed that the predicted probability increased from a low of 1.0% at 9 am to a high of 4.2% at 4 pm. The two most common event types (pain management and postoperative nausea and vomiting) may be primary determinants of these effects.
  
  
  CONCLUSIONS
  Our results indicate that clinical outcomes may be different for patients anesthetized at the end of the work day compared with the beginning of the day. Although this may result from patient related factors, medical care delivery factors such as case load, fatigue, and care transitions may also be influencing the rate of anesthetic AEs for cases that start in the late afternoon.
authors.affiliation: Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710, USA. melanie.wright@duke.edu
authors.forename: M C
authors.initials: MC
authors.lastname: Wright
authors.forename: B
authors.initials: B
authors.lastname: Phillips-Bute
authors.forename: J B
authors.initials: JB
authors.lastname: Mark
authors.forename: M
authors.initials: M
authors.lastname: Stafford-Smith
authors.forename: K P
authors.initials: KP
authors.lastname: Grichnik
authors.forename: B C
authors.initials: BC
authors.lastname: Andregg
authors.forename: J M
authors.initials: JM
authors.lastname: Taekman
mesh_terms: D000776:Anesthesiology / Q000592:standards* / Q000706:statistics & numerical data; D001071:Appointments and Schedules; D005221:Fatigue; D005260:Female; D006785:Hospitals, University / Q000592:standards; D006801:Humans; D008297:Male; D008485:Medical Audit / Q000379:methods*; D008508:Medication Errors / Q000145:classification / Q000706:statistics & numerical data*; D009657:North Carolina; D019370:Observation; D009873:Operating Rooms / Q000592:standards* / Q000706:statistics & numerical data; D017063:Outcome Assessment, Health Care; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D016016:Proportional Hazards Models; D012308:Risk Management / Q000379:methods*; D018571:Sentinel Surveillance; D013997:Time Factors; D014940:Work Schedule Tolerance