title: Evaluation of an emergency department lean process improvement program to reduce length of stay.
abstract: OBJECTIVE
  In recent years, lean principles have been applied to improve wait times in the emergency department (ED). In 2009, an ED process improvement program based on lean methods was introduced in Ontario as part of a broad strategy to reduce ED length of stay and improve patient flow. This study seeks to determine the effect of this program on ED wait times and quality of care.
  
  
  METHODS
  We conducted a retrospective cohort study of all ED visits at program and control sites during 3 program waves from April 1, 2007, to June 30, 2011, in Ontario, Canada. Time series analyses of outcomes before and after the program and difference-in-differences analyses comparing changes in program sites with control sites were conducted.
  
  
  RESULTS
  In before-after models among program sites alone, 90th percentile ED length of stay did not change in wave 1 (-14 minutes [95% confidence interval {CI} -47 to 20]) but decreased after wave 2 (-87 [95% CI -108 to -66]) and wave 3 (-33 [95% CI -50 to -17]); median ED length of stay decreased after wave 1 (-18 [95% CI -24 to -12]), wave 2 (-23 [95% CI -27 to -19]), and wave 3 (-15 [95% CI -18 to -12]). In all waves, decreases were observed in time to physician assessment, left-without-being-seen rates, and 72-hour ED revisit rates. In the difference-in-difference models, in which changes in program sites were compared with controls, the program was associated with no change in 90th percentile ED length of stay in wave 2 (17 [95% CI -0.2 to 33]) and increases in wave 1 (23 [95% CI 0.9 to 45]) and wave 3 (31 [95% CI 10 to 51]), modest reductions in median ED length of stay in waves 2 and 3 alone, and a decrease in time to physician assessment in wave 3 alone.
  
  
  CONCLUSIONS
  Although the program reduced ED waiting times, it appeared that its benefits were diminished or disappeared when compared with that of control sites, which were exposed to system-wide initiatives such as public reporting and pay for performance. This study suggests that further evaluation of the effectiveness of lean methods in the ED is warranted before widespread implementation.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada. Electronic address: marian.vermeulen@ices.on.ca.
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Vermeulen
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; Dartmouth Institute for Health Policy and Clinical Practice, Giesel School of Medicine at Dartmouth, Hanover, NH.
authors.forename: Therese A
authors.initials: TA
authors.lastname: Stukel
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; Division of Paediatric and Emergency Medicine, Hospital for Sick Children, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Astrid
authors.initials: A
authors.lastname: Guttmann
authors.affiliation: Department of Emergency Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Rowe
authors.affiliation: Centre for Studies in Family Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: Merrick
authors.initials: M
authors.lastname: Zwarenstein
authors.affiliation: Rotman School of Management, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: Golden
authors.affiliation: Cass Business School, City University, London, UK.
authors.forename: Amit
authors.initials: A
authors.lastname: Nigam
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Geoff
authors.initials: G
authors.lastname: Anderson
authors.affiliation: University Health Network, Toronto, Ontario, Canada.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Bell
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; Division of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Trauma, Emergency and Critical Care Program, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schull
mesh_terms: D004636:Emergency Service, Hospital / Q000458:organization & administration* / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D009864:Ontario; D015397:Program Evaluation; D058996:Quality Improvement / Q000458:organization & administration; D012189:Retrospective Studies