title: Using lean-based systems engineering to increase capacity in the emergency department.
abstract: BACKGROUND
  While emergency department (ED) crowding has myriad causes and negative downstream effects, applying systems engineering science and targeting throughput remains a potential solution to increase functional capacity. However, the most effective techniques for broad application in the ED remain unclear. We examined the hypothesis that Lean-based reorganization of Fast Track process flow would improve length of stay (LOS), percent of patients discharged within one hour, and room use, without added expense.
  
  
  METHODS
  This study was a prospective, controlled, before-and-after analysis of Fast Track process improvements in a Level 1 tertiary care academic medical center with >95,000 annual patient visits. We included all adult patients seen during the study periods of 6/2010-10/2010 and 6/2011-10/2011, and data were collected from an electronic tracking system. We used concurrent patients seen in another care area used as a control group. The intervention consisted of a simple reorganization of patient flow through existing rooms, based in systems engineering science and modeling, including queuing theory, demand-capacity matching, and Lean methodologies. No modifications to staffing or physical space were made. Primary outcomes included LOS of discharged patients, percent of patients discharged within one hour, and time in exam room. We compared LOS and exam room time using Wilcoxon rank sum tests, and chi-square tests for percent of patients discharged within one hour.
  
  
  RESULTS
  Following the intervention, median LOS among discharged patients was reduced by 15 minutes (158 to 143 min, 95%CI 12 to 19 min, p<0.0001). The number of patients discharged in <1 hr increased by 2.8% (from 6.9% to 9.7%, 95%CI 2.1% to 3.5%, p<0.0001), and median exam room time decreased by 34 minutes (90 to 56 min, 95%CI 31 to 38 min, p<0.0001). In comparison, the control group had no change in LOS (265 to 267 min) or proportion of patients discharged in <1 hr (2.9% to 2.9%), and an increase in exam room time (28 to 36 min, p<0.0001).
  
  
  CONCLUSIONS
  In this single center trial, a focused Lean-based reorganization of patient flow improved Fast Track ED performance measures and capacity, without added expense. Broad multi-centered application of systems engineering science might further improve ED throughput and capacity.
authors.affiliation: Massachusetts General Hospital, Department of Emergency Medicine, Boston, Massachusetts.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: White
authors.affiliation: Massachusetts General Hospital, Department of Emergency Medicine, Boston, Massachusetts.
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Massachusetts General Hospital, Department of Emergency Medicine, Boston, Massachusetts.
authors.forename: Beth G
authors.initials: BG
authors.lastname: Grabowski
authors.affiliation: Massachusetts General Hospital, Department of Emergency Medicine, Boston, Massachusetts.
authors.forename: David F M
authors.initials: DF
authors.lastname: Brown
mesh_terms: D016022:Case-Control Studies; D003441:Crowding; D017598:Efficiency, Organizational / Q000191:economics; D004632:Emergency Medical Services / Q000191:economics / Q000458:organization & administration*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D010351:Patient Discharge; D017060:Patient Satisfaction; D011446:Prospective Studies; D017749:Total Quality Management; D014218:Triage; D014481:United States / Q000453:epidemiology