title: The impact of computerized provider order entry on emergency department flow.
abstract: OBJECTIVE
  Computerized provider order entry (CPOE) has been established as a method to improve patient safety by avoiding medication errors; however, its effect on emergency department (ED) flow remains undefined. We examined the impact of CPOE implementation on three measures of ED throughput: wait time (WT), length of stay (LOS), and the proportion of patients that left without being seen (LWBS).
  
  
  METHODS
  We conducted a retrospective cohort study of all ED patients of 18 years and older presenting to London Health Sciences Centre during July and August 2013 and 2014, before and after implementation of a CPOE system. The three primary variables were compared between time periods. Subgroup analyses were also conducted within each Canadian Triage and Acuity Scale (CTAS) level (1-5) individually, as well as for admitted patients only.
  
  
  RESULTS
  A significant increase in WT of 5 minutes (p=0.036) and LOS of 10 minutes (p=0.001), and an increase in LWBS from 7.2% to 8.1% (p=0.002) was seen after CPOE implementation. Admitted patients' LOS increased by 63 minutes (p<0.001), the WT of CTAS 3 and 5 patients increased by 6 minutes (p=0.001) and 39 minutes (p=0.005), and LWBS proportion increased significantly for CTAS 3-5 patients, from 24.3% to 42.0% (p<0.001) for CTAS 5 patients specifically.
  
  
  CONCLUSIONS
  CPOE implementation detrimentally impacted all patient flow throughput measures that we examined. The most striking clinically relevant result was the increase in LOS of 63 minutes for admitted patients. This raises the question as to whether the potential detrimental effects to patient safety of CPOE implementation outweigh its benefits.
authors.affiliation: *Department of Emergency Medicine,London Health Sciences Centre,London,ON.
authors.forename: Andrew
authors.initials: A
authors.lastname: Gray
authors.affiliation: *Department of Emergency Medicine,London Health Sciences Centre,London,ON.
authors.forename: Christopher M B
authors.initials: CM
authors.lastname: Fernandes
authors.affiliation: *Department of Emergency Medicine,London Health Sciences Centre,London,ON.
authors.forename: Kristine
authors.initials: K
authors.lastname: Van Aarsen
authors.affiliation: *Department of Emergency Medicine,London Health Sciences Centre,London,ON.
authors.forename: Melanie
authors.initials: M
authors.lastname: Columbus
mesh_terms: D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D002170:Canada; D015331:Cohort Studies; D016208:Databases, Factual; D017598:Efficiency, Organizational; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D050316:Medical Order Entry Systems / Q000458:organization & administration*; D008875:Middle Aged; D061214:Patient Safety; D015397:Program Evaluation; D012189:Retrospective Studies; D014218:Triage / Q000379:methods*; D014850:Waiting Lists; D055815:Young Adult
keywords: computerized; electronic; emergency department; length of stay; orders; wait times