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Lean Thinking in Emergency Departments: A Critical Review

  • Richard J. Holden
    Correspondence
    Address for correspondence: Richard J. Holden, PhD, Center for Quality and Productivity Improvement, University of Wisconsin-Madison, 1550 Engineering Dr, Madison, WI 53706; 46-0-72-200-6013, fax 608-262-8454
    Affiliations
    School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI, and the Division of Ergonomics, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
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      Emergency departments (EDs) face problems with crowding, delays, cost containment, and patient safety. To address these and other problems, EDs increasingly implement an approach called Lean thinking. This study critically reviewed 18 articles describing the implementation of Lean in 15 EDs in the United States, Australia, and Canada. An analytic framework based on human factors engineering and occupational research generated 6 core questions about the effects of Lean on ED work structures and processes, patient care, and employees, as well as the factors on which Lean's success is contingent. The review revealed numerous ED process changes, often involving separate patient streams, accompanied by structural changes such as new technologies, communication systems, staffing changes, and the reorganization of physical space. Patient care usually improved after implementation of Lean, with many EDs reporting decreases in length of stay, waiting times, and proportion of patients leaving the ED without being seen. Few null or negative patient care effects were reported, and studies typically did not report patient quality or safety outcomes beyond patient satisfaction. The effects of Lean on employees were rarely discussed or measured systematically, but there were some indications of positive effects on employees and organizational culture. Success factors included employee involvement, management support, and preparedness for change. Despite some methodological, practical, and theoretic concerns, Lean appears to offer significant improvement opportunities. Many questions remain about Lean's effects on patient health and employees and how Lean can be best implemented in health care.
      SEE EDITORIAL, P. 279.

      Introduction

      The need for improvement in emergency departments (EDs) with respect to the cost of care, the speed of service, crowding, and patient safety is now widely accepted.
      Institute of Medicine
      Hospital-Based Emergency Care: At the Breaking Point.
      • Berger E.
      A $9,000 bill to diagnose shingles?.
      • Kellerman A.L.
      Crisis in the emergency department.
      • Smits M.
      • Groenewegen P.P.
      • Timmermans D.R.M.
      • et al.
      The nature and causes of unintended events reported at ten emergency departments.
      In an attempt to achieve broad improvement, health care organizations worldwide increasingly adopt an approach called “Lean thinking” (see Figure 1 for a description of Lean).
      • Young T.P.
      • McClean S.I.
      A critical look at Lean thinking in healthcare.
      In a 2009 survey of US hospitals, 53% reported having implemented Lean to some extent; of those hospitals, 60% reported implementing Lean in the ED.
      American Society for Quality
      Hospitals see benefits of Lean and Six Sigma [press release].
      Furthermore, some public health care systems, including the UK National Health Service,
      • Jones D.
      • Mitchell A.
      Lean Thinking for the NHS.
      have adopted or are planning to adopt Lean as a key lever for decreasing costs and improving the quality and safety of care.
      Lean thinking is a bundle of concepts, methods, and tools derived from the Toyota Production System, the production philosophy of Toyota Motor Corporation. Lean was first implemented in US auto manufacturing in an attempt to replicate Toyota's success and has subsequently spread to other manufacturers (eg, Boeing), to service industry (eg, Tesco), and to the public sector (eg, UK National Health Service). Key principles of Lean are listed in Figure 1. Chief among them is the need to eliminate unnecessary waste. Waste is anything that does not add value to the customer. For example, if the ED patient is the customer, 2 wastes might be waiting to be seen or undergoing (and paying for) a duplicate test. As waste is eliminated, products (or patients) flow smoothly, continuously, and without errors from one step to another. After work is completed at one step, it is not pushed to the next step; instead, work is pulled when it is ready to be processed at the next step so that work does not pile up. Problems that arise in the process are to be identified immediately, their causes understood, and a solution applied. Both frontline workers and management are responsible for the quality of work, and both are involved in the problem solving process, often by participating in rapid continuous improvement sessions called kaizen. Indeed, although the support and participation of leadership is crucial, contemporary prescriptions of Lean insist that workers be involved and empowered to inspect and improve their own work. Workers and management have at their disposal numerous tools and methods to implement the above principles (Figure 1).
      The much-celebrated success of Lean in manufacturing
      • Womack J.P.
      • Jones D.T.
      • Roos D.
      The Machine That Changed the World.
      and success stories of Lean in the National Health Service and other health care systems
      • Spear S.J.
      Fixing health care from the inside, today.
      • Toussaint J.
      Writing the new playbook for US health care: lessons from Wisconsin.
      • Nelson-Peterson D.L.
      • Leppa C.J.
      Creating an environment for caring using Lean principles of the Virginia Mason Production System.
      • Fillingham D.
      Lean Healthcare: Improving the Patient's Experience.
      have resulted in a strong push for introducing Lean to health care
      • Cooper R.G.
      • Mohabeersingh C.
      Lean thinking for medical practices.
      • Ben-Tovim D.I.
      Letters Seeing the picture through “Lean thinking.”.
      • Miller D.
      Going Lean in Health Care.
      • Bush R.W.
      Reducing waste in US health care systems.
      and more particularly to the ED.
      • Decker W.W.
      • Stead L.G.
      Application of Lean thinking in health care: a role in emergency departments globally.
      • Eitel D.R.
      • Rudkin S.E.
      • Malvehy M.A.
      • et al.
      Improving service quality by understanding emergency department flow: a white paper and position statement prepared for the American Academy of Emergency Medicine.
      • Horwitz L.I.
      • Meredith T.
      • Schuur J.D.
      • et al.
      Dropping the baton: a qualitative analysis of failures during the transition from emergency department to inpatient care.
      • Kulkarni R.G.
      Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.
      • Smallbane S.
      Lean thinking redesign: a weighty matter.
      Given enthusiasm about Lean as an approach to improving emergency care, this article critically reviews and analyzes the empirical literature on the implementation of Lean in the ED. The present review differs from previous work
      • Spear S.J.
      Fixing health care from the inside, today.
      • Vest J.R.
      • Gamm L.D.
      A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare.
      • Hughes R.G.
      Tools and strategies for quality improvement and patient safety.
      • Cooper R.G.
      • Mohabeersingh C.
      Lean thinking in a healthcare system—innovative roles.
      • Brandao de Souza L.
      Trends and approaches in Lean healthcare.
      in 5 ways. First, it focuses specifically on the ED. Second, it reviews how Lean affects health care employees in addition to patients. Third, it assesses previous studies for evidence of undesirable and null effects of Lean in addition to desirable effects and in general takes a much-needed critical approach.
      • Brandao de Souza L.
      Trends and approaches in Lean healthcare.
      • Winch S.
      • Henderson A.J.
      Making cars and making health care: a critical review.
      • Young T.P.
      • McClean S.I.
      Some challenges facing Lean thinking in healthcare.
      Fourth, it analyzes the factors that may contribute to variability in Lean's success. Fifth, this study systematically analyzes each previous study according to an analytic framework, rather than using studies to build a narrative about Lean in health care. That framework, described below, is based on human factors/systems engineering principles and on occupational research on Lean outside of health care.

      Methods

      The analytic framework used to generate the core research questions for this review (Figure 2) depicts Lean as having transformative effects on the structure and process of ED work. Structure refers to work system elements such as tools and technology, worker factors (eg, education/training, responsibilities), organizational factors (eg, policy, staffing, incentives), communication systems, and the physical environment (eg, spatial arrangement, noise, lighting).
      • Carayon P.
      • Schoofs Hundt A.
      • Karsh B.
      • et al.
      Work system design for patient safety: the SEIPS model.
      • Karsh B.
      • Holden R.J.
      • Alper S.J.
      • et al.
      A human factors engineering paradigm for patient safety—designing to support the performance of the health care professional.
      Process refers to the actual activities of patient care and related work
      • Karsh B.
      • Holden R.J.
      • Alper S.J.
      • et al.
      A human factors engineering paradigm for patient safety—designing to support the performance of the health care professional.
      and the “flow” of the patient through the ED or broader care delivery system.
      • Ben-Tovim D.I.
      • Dougherty M.L.
      • O'Connell T.J.
      • et al.
      Patient journeys: the process of clinical redesign.
      Figure thumbnail gr2
      Figure 2A model of Lean in health care, proposing that (a) Lean affects patient care and employees indirectly by changing work structure and process, (b) Lean affects employees directly, (c) employee and patient care changes can affect one another, and (d) Lean is implemented in a particular context and that the success of Lean is contingent on how a particular Lean implementation fits into the local context.
      Understanding how Lean transforms work structure and process is important because those transformations will determine patient care quality and safety indicators such as length of stay, medication errors, and patient satisfaction.
      • Karsh B.
      • Holden R.J.
      • Alper S.J.
      • et al.
      A human factors engineering paradigm for patient safety—designing to support the performance of the health care professional.

      Holden RJ. Cognitive performance-altering effects of electronic medical records: an application of the human factors paradigm for patient safety. Cognition Technol Work. In press. doi:10.1007/s10111-10010-10141-10118 .

      How Lean affects patient care, albeit indirectly through structure and process change, ultimately determines the success of Lean.
      Arguably, another necessary, perhaps sufficient, indicator of Lean's success is the efficient use of limited resources (eg, financial, material, human resources).
      By transforming work structures and processes, Lean also affects the employees responsible for carrying out the work, as studies of Lean outside of health care demonstrate.
      • Conti R.
      • Angelis J.
      • Cooper C.
      • et al.
      The effects of Lean production on worker job stress.
      • Parker S.K.
      Longitudinal effects of Lean production on employee outcomes and the mediating role of work characteristics.
      • Jackson P.R.
      • Mullarkey S.
      Lean production teams and health in garment manufacture.
      • Landsbergis P.A.
      The changing organization of work and the safety and health of working people: a commentary.
      • Landsbergis P.A.
      • Cahill J.
      • Schnall P.
      The impact of Lean production and related new systems of work organization on worker health.
      A representative finding comes from the study by Sprigg and Jackson
      • Sprigg C.A.
      • Jackson P.R.
      Call centers as Lean service environments: job-related strain and the mediating role of work design.
      of call center employees: the introduction of Lean imposed dialog scripting and performance monitoring; this led to lower job control, task variety, skill use, and role clarity and higher workload and role conflict; those changes in working conditions were then found to relate to employees' job strain outcomes (job-related anxiety and depression). The effects of Lean on employees may also be desirable ones.
      • de Treville S.
      • Antonakis J.
      Could Lean production job design be intrinsically motivating? contextual, configurational, and levels-of-analysis issues.
      • Schouteten R.
      • Benders J.
      Lean production assessed by Karasek's job demand-job control model.
      Apart from the employee effects of Lean-related changes to the actual work, there may also be a direct path by which Lean affects employees. For example, 2 intended effects of implementing Lean are to shift employees from merely doing their work to looking for ways to improve it and the empowerment of workers to suggest and implement changes.
      • Ohno T.
      Toyota Production System: Beyond Large-Scale Production.
      Similarly, changes in motivation, information, and social standing, to give 3 examples, might result from the mere involvement of workers in Lean projects, independent of the work changes brought about by the actual projects. Another possible direct effect of Lean is the anxiety brought about by fears of losing one's job or having a less satisfying job after clinical work is made more efficient.
      If workers are affected by Lean, resulting in higher or lower motivation, satisfaction, anxiety, task control, and more, it is reasonable to suggest that patient care, and thus patient outcomes, will improve or suffer. Following this logic, the Mehta and Shah
      • Mehta V.
      • Shah H.
      Characteristics of a work organization from a Lean perspective.
      model of employee effects of Lean proposes that employee outcomes both affect and are affected by “organizational outcomes” such as “productivity” and “performance.” In the health care setting, however, the relationship of interest is between employee conditions and outcomes on one hand and the quality, safety, and efficiency of patient care on the other.
      • Carayon P.
      • Schoofs Hundt A.
      • Karsh B.
      • et al.
      Work system design for patient safety: the SEIPS model.
      “Lean production is … not a single unitary production concept, either in its design or in its implementation.”
      • Parker S.K.
      Longitudinal effects of Lean production on employee outcomes and the mediating role of work characteristics.
      Instead, organizations select among numerous principles, tools, methods, and philosophies.
      • Pettersen J.
      Defining Lean production: some conceptual and practical issues.
      Generic Lean principles are interpreted and adapted for each organization's unique local context.
      • Black J.
      Transforming the patient care environment with Lean Six Sigma and realistic evaluation.
      This has led researchers to propose that the effects of Lean are contingent on how and where Lean is implemented.
      • Parker S.K.
      Longitudinal effects of Lean production on employee outcomes and the mediating role of work characteristics.
      • Sprigg C.A.
      • Jackson P.R.
      Call centers as Lean service environments: job-related strain and the mediating role of work design.
      • Mehta V.
      • Shah H.
      Characteristics of a work organization from a Lean perspective.
      The components of the analytic framework discussed above yield 6 study questions that guided the analysis of reviewed studies of Lean in the ED:
      • How does Lean transform work structures and work processes?
      • How does Lean affect patient care (quality, safety, efficiency)?
      • How does Lean affect employee working conditions (eg, autonomy, workload) and outcomes (eg, motivation, satisfaction) indirectly by transforming work structures and processes?
      • How does Lean affect employee outcomes directly, independent of changes to work structures and processes?
      • How are patient care effects and employee effects of Lean linked?
      • How are patient care and employee effects of Lean contingent on the features of (a) the organization implementing Lean and (b) the design and implementation of Lean?
      The scholarly literature spanning January 2005 to January 2010 was searched for articles describing Lean implementation in the ED. Three database searches were conducted: (1) the medical database PubMed, using the search string “Lean OR Toyota Production System;” (2) the business/management database ABI/INFORM (Scholarly Journals) using “Lean OR Toyota Production System” and a collection of health care terms (eg, hospital*, patient*, health care, clinic*, emergency department*); and (3) the interdisciplinary database Google Scholar using “emergency room OR emergency medicine OR accident & emergency OR emergency department AND Lean production OR Lean thinking.” Twelve specific journals, including Annals of Emergency Medicine, Journal of Emergency Medicine, Emergency Medicine Journal, American Journal of Emergency Medicine, and International Journal of Emergency Medicine, were searched using the terms “Lean” and “Toyota.” Finally, the references of retrieved articles and of existing articles from a broad literature collection on Lean in health care were searched for other relevant articles.
      Nonempirical articles and articles reporting on work design or improvement projects not identified as Lean
      • Rodriguez K.L.
      • Burkitt K.H.
      • Sevick M.A.
      • et al.
      Assessing processes of care to promote timely initiation of antibiotic therapy for emergency department patients hospitalized for pneumonia.
      • Banerjee A.
      • Mbamalu D.
      • Hinchley G.
      The impact of process re-engineering on patient throughput in emergency departments in the UK.
      • Travers J.P.
      • Lee F.C.Y.
      Avoiding prolonged waiting time during busy periods in the emergency department: is there a role for the senior emergency physician in triage?.
      were excluded from the review. Conference abstracts
      • Farley H.
      • Hines D.
      • Ross E.
      • et al.
      A Lean-based triage redesign process improves door-to-room times and decreases number of patients at triage [abstract].
      • Leaver C.
      • Guttmann A.
      • Rowe B.H.
      • et al.
      Qualitative results from an Ontario hospital patient flow improvement program pilot to improve emergency department waiting times [abstract].
      • Kaale R.L.
      • Vega D.D.
      • Messner K.
      • et al.
      Time value stream mapping as a tool to measure patient flow through emergency department triage [abstract].
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      Initiatives in redesigning emergency care to improve patient flow [abstract].
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      Red and blue teams: changing processes to improve patient flow [abstract].
      • Massucci J.L.
      • Farley H.
      • Laskowski Jones L.
      • et al.
      Reduction in emergency department fast track length of stay [abstract].
      • Munro P.T.
      • Gillespie C.
      • Begbie K.
      • et al.
      Resource-neutral performance improvement in an urban general hospital emergency department [abstract].
      • Retallick N.
      Patient process improvements in the emergency department [abstract].
      • Schuur J.D.
      • Collins D.
      • Smith A.
      • et al.
      Use of Lean techniques to simplify admission procedures and decreased ED process time [abstract].

      Stratton R, Knight A. Utilising buffer management to manage patient flow. 16th International Annual EurOMA Conference; June 14-17, 2009; Goteborg, Sweden.

      and similar condensed publications
      • Weinstock M.
      How one hospital slashed ED waits.
      • Foster R.
      Windsor Regional Hospital emergency department revolutionized.
      were excluded because they provided insufficient information. Larger-scale (eg, hospital-wide) studies that included the ED were excluded because of space limitations and difficulty extracting ED-specific content.
      • Toussaint J.
      Writing the new playbook for US health care: lessons from Wisconsin.
      • Stuenkel K.
      • Faulkner T.
      A community hospital's journey into Lean Six Sigma.
      • Burkitt K.H.
      • Mor M.K.
      • Jain R.
      • et al.
      Toyota Production System quality improvement initiative improves perioperative antibiotic therapy.
      • Stapleton F.B.
      • Hendricks J.
      • Hagan P.
      • et al.
      Modifying the Toyota Production System for continuous performance improvement in an academic children's hospital.
      • Fine B.A.
      • Golden B.
      • Hannam R.
      • et al.
      Leading Lean: a Canadian healthcare leader's guide.
      • Kim C.S.
      • Spahlinger D.A.
      • Kin J.M.
      • et al.
      Implementation of Lean thinking: one health system's journey.
      • Van den Heuvel J.
      • Does R.J.M.M.
      • de Koning H.
      Lean Six Sigma in a hospital.
      • MacLeod H.
      • Bell B.
      • Deane K.
      • et al.
      Creating sustained improvements in patient access and flow: experiences from three Ontario healthcare institutions.
      • Slunecka F.
      • Farris D.
      Lean principles provide opportunities for Catholic health care organizations.
      • Fillingham D.
      Can Lean save lives?.
      Studies of pre-ED triage only were also excluded.
      • Isaacs A.A.
      • Hellenberg D.A.
      Implementing a structured triage system at a community health centre using Kaizen.
      Finally, studies not published in the English language were excluded.

      Results

      Eighteen articles describing Lean initiatives in 15 EDs met inclusion criteria (Table 1).
      Table 1List of reviewed studies and descriptions of study sites and Lean project teams.
      StudyStudy SiteProject Team Composition
      Al Darrab et al, 2006
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      EDs at Hamilton Health Sciences, a 3-site tertiary/quaternary care facility, CanadaEmergency medicine/cardiology leaders and quality improvement facilitators set improvement goals. Project team included pharmacists, staff nurses, managers, educators, residents, nursing program directors, project coleaders from the ED and cardiology, quality improvement facilitators, emergency medical services representatives.
      Ben-Tovim et al, 2007,
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bolch D.
      • et al.
      Lean thinking across a hospital: redesigning care at the Flinders Medical Centre.
      2008,
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bennett D.M.
      • et al.
      Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      ED at Flinders Medical Centre, a 500-bed community teaching hospital, AustraliaFacilitators worked with senior staff to make initial assessments and then involved multidisciplinary groups of frontline staff to diagnose problems, document the process, and implement and evaluate process redesign. “Participants were drawn from the full range of staff working within the ED, from patient care assistants and clerical staff to junior and senior nursing and medical staff.”
      King et al, 2006
      • King D.L.
      • Ben-Tovim D.I.
      • Bassham J.
      Redesigning emergency department patient flows: application of Lean thinking to health care.
      Reviewed in Cooper and Mohabeersingh.24
      Dickson et al, 2008,
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      2009
      • Dickson E.W.
      • Singh S.
      • Cheung D.S.
      • et al.
      Application of Lean manufacturing techniques in the emergency department.
      Level I trauma center at University of Iowa Hospitals and Clinics, a 700-bed teaching hospitalImprovement team composed of 2 ED physicians, 2 ED nurses, an ED physician assistant, 2 non-ED physicians, 2 radiology technicians, a laboratory technician, 5 industrial engineers, and 5 external participants from a local business council (representing the patient perspective)
      Dickson et al, 2009
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      Hospital A likely refers to Eller76 and Hospital D to Dickson et al.73,74
      • Hospital A: ED at a 690-bed teaching hospital, unspecified urban location
      • Hospital B: ED at an 889-bed community hospital, unspecified urban location
      • Hospital C: Level II trauma center at a 461-bed community hospital, unspecified location
      • Hospital D: Level I trauma center at a 700-bed teaching hospital, unspecified rural location
      • Hospital A: Improvement driven by consultant and focus area leader. “Frontline workers not initially asked to provide ideas for process redesign but in the course of implementation were inspired to suggest incremental process improvements.”
      • Hospital B: “Frontline workers,” “led by a consultant team”
      • Hospital C: ED management. “Ideas of frontline workers not sought.”
      • Hospital D: See Dickson et al, 2008,
        • Dickson E.W.
        • Anguelov Z.
        • Bott P.
        • et al.
        The sustainable improvement of patient flow in an emergency treatment centre using Lean.
        2009,
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
        above
      Eller, 2009
      • Eller A.
      Rapid assessment and disposition: applying Lean in the emergency department.
      ED at St. Luke's Episcopal Hospital, a 900-bed faith-based teaching hospital“Staff members”
      Ieraci et al, 2008
      • Ieraci S.
      • Digiusto E.
      • Sonntag P.
      • et al.
      Streaming by case complexity: evaluation of a model for emergency department fast track.
      Reviewed in Cooper and Mohabeersingh.24
      ED at Bankstown Hospital, a 400-bed referral hospital, AustraliaIntervention developed in “workshop sessions involving key clinical and management staff within the ED”
      Jacobson et al, 2009
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      Level I trauma center at Vanderbilt University Medical Center, a 600-bed teaching hospitalAny physician (resident or attending) wanting to submit an idea, concern, or observation. Although 17% of submissions were from nurses and other staff, the system was initially aimed at physicians.
      Kelly et al, 2007
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      • et al.
      Improving emergency department efficiency by patient streaming to outcomes-based teams.
      Reviewed in Cooper and Mohabeersingh.24
      ED at Western Hospital, a 300-bed community teaching hospital serving adult patients only, Australia“Collaborative design and implementation process involving all professional groups and grades of staff”
      Kulkarni, 2007,
      • Kulkarni R.G.
      Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.
      2008
      • Kulkarni R.G.
      A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      ED at Yale–New Haven Hospital, a 950-bed teaching hospitalTeam included “representatives from the emergency department, such as nursing, midlevel staff, staff physicians, resident physicians, greeters, registration, security, and technicians/patient care assistants” and “hospital leadership and representatives from inpatient physician and nursing leadership as well as general hospital departments—such as transport and environmental services.”
      Ng et al, 2010
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      ED at Hôtel-Dieu Grace Hospital, a 300-bed faith-based tertiary care hospital, CanadaA Lean consultant and “emergency physicians; nurses; nurse practitioners; porters; clerks; cleaning staff; administrators; the ED director, unit manager and educator; the hospital's senior vice-president; and representatives from diagnostic imaging, laboratory, respiratory therapy, home care and information services.”
      Parks et al, 2008
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      Level I trauma center at Parkland Memorial Hospital, a 950-bed community teaching hospitalProject team included hospital administration, trauma surgeons and nursing staff, and performance improvement personnel trained in Lean Six Sigma
      Schooley, 2008
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      ED at Presbyterian Hospital, a 531-bed regional medical center, part of a not-for-profit integrated health care systemAt first, Lean consultant and managers only. Later, physician, nurses, and other staff were interviewed and became involved in suggesting and implementing changes. Improvement teams included both supporters of change and resistors who were also social leaders in the organization.
      Stephens-Lee, 2006
      • Stephens-Lee C.
      Work flow analysis of admitted patients.
      ED at Dartmouth General Hospital, a 131-bed community hospitalLean consultant and “nurses and clerks from the ED and inpatient units, the bed manager, an inpatient Health Services manager, chief of staff and engineers.”
      Woodward et al, 2007
      • Woodward G.A.
      • Godt M.G.
      • Fisher K.
      • et al.
      Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      ED at Seattle Children's Hospital, a 250-bed pediatric teaching hospitalNot described
      low asterisk Reviewed in Cooper and Mohabeersingh.
      • Cooper R.G.
      • Mohabeersingh C.
      Lean thinking in a healthcare system—innovative roles.
      Hospital A likely refers to Eller
      • Eller A.
      Rapid assessment and disposition: applying Lean in the emergency department.
      and Hospital D to Dickson et al.
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Dickson E.W.
      • Singh S.
      • Cheung D.S.
      • et al.
      Application of Lean manufacturing techniques in the emergency department.
      Study sites tended to be larger teaching hospitals in the United States, Australia, or Canada. Project team composition varied among sites, but with one exception (Dickson et al
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      ), all Lean involved frontline staff in some way. The staff involved ranged from clinicians to clerks, assistants, engineers, and representatives of the patient community. Their involvement ranged from providing suggestions to designing and implementing changes. Usually, a quality improvement facilitator or Lean consultant was involved, and management or senior staff were often involved throughout Lean initiatives.
      In most cases, Lean was the sole approach used. Three studies
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      combined Lean with Six Sigma, a quality improvement method based on minimizing variability. Another “borrowed from many other manufacturing philosophies.”
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bennett D.M.
      • et al.
      Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      In other studies, changes such as new leadership,
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      increased staffing,
      • Ieraci S.
      • Digiusto E.
      • Sonntag P.
      • et al.
      Streaming by case complexity: evaluation of a model for emergency department fast track.
      or other ongoing quality improvement projects
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      were concomitant with Lean.
      The typical approach to Lean began with process mapping, wherein the current process steps were diagramed. Time consumed for each step was measured
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Stephens-Lee C.
      Work flow analysis of admitted patients.
      or estimated,
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      and in one study the location of staff at each step was diagrammed.
      • Kulkarni R.G.
      A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      Some type of analysis typically followed, wherein bottlenecks, waste, or other problems were identified and causes or correlates of those problems were sought. After brainstorming and sometimes future-state mapping of possible improvements, project teams undertook process redesign. Often, changes were evaluated and adjusted in an iterative way; such iteration is a vital component of the plan-do-study-act cycle adopted by some studies
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • King D.L.
      • Ben-Tovim D.I.
      • Bassham J.
      Redesigning emergency department patient flows: application of Lean thinking to health care.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      and of the kaizen rapid process improvement workshops reported in other studies.
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Woodward G.A.
      • Godt M.G.
      • Fisher K.
      • et al.
      Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      Kaizen, or “small, low-cost, low-risk improvements that can be easily implemented,”
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      is a cornerstone of Lean and is not surprisingly the chief and sometimes sole Lean tool used in health care.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      Other components of Lean included education on Lean,
      • King D.L.
      • Ben-Tovim D.I.
      • Bassham J.
      Redesigning emergency department patient flows: application of Lean thinking to health care.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      goal setting,
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      • et al.
      Improving emergency department efficiency by patient streaming to outcomes-based teams.
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      formal root cause analysis,
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      • et al.
      Improving emergency department efficiency by patient streaming to outcomes-based teams.
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      and various types of data collection.
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Stephens-Lee C.
      Work flow analysis of admitted patients.
      Table 2 depicts how Lean changed work structure and process in the studied EDs. Process redesign was a formal component of all EDs' Lean initiatives except in one ED in which redesign was planned but not yet implemented.
      • Stephens-Lee C.
      Work flow analysis of admitted patients.
      Table 2 lists examples of process change, many of which involved some separation of patients into “streams” or “tracks.” New or transformed processes were accompanied by new standard operating procedures, consistent with the focus of Lean on creating standard work. As depicted in Figure 2, Lean does not simply alter the process of work: numerous work structure changes accompanied process change. These included (a) new data collection and monitoring systems, (b) education and training, (c) changes to tools and technologies, (d) new systems for communication and teamwork, (e) changes in staffing, roles, and responsibilities, and (f) reassignment or reorganization of physical space. Table 2 provides examples of work system changes within each category.
      Table 2Work process and work structure changes resulting from implementation of Lean.
      Process ChangesSpecific Examples
      New processes and related operating procedures
      • Rapid assessment and disposition process
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Separate express care track for patients to be treated more quickly during high-volume times
        • Schooley J.
        No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Fast track process for low-complexity patients
        • Ieraci S.
        • Digiusto E.
        • Sonntag P.
        • et al.
        Streaming by case complexity: evaluation of a model for emergency department fast track.
      • Separate streaming of likely-admitted versus likely-discharged patients
        • King D.L.
        • Ben-Tovim D.I.
        • Bassham J.
        Redesigning emergency department patient flows: application of Lean thinking to health care.
        • Kelly A.-M.
        • Bryant M.
        • Cox L.
        • et al.
        Improving emergency department efficiency by patient streaming to outcomes-based teams.
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
        and likely-discharged patients treated in order of arrival
        • King D.L.
        • Ben-Tovim D.I.
        • Bassham J.
        Redesigning emergency department patient flows: application of Lean thinking to health care.
      • Streaming of patients into 3 “pods” (complex, medium, and fast)
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Script for calling ambulance
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Immediate rooming of patients and bedside registration, when possible
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • Test orders
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
        or other work (eg, identifying need for home care)
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
        conducted earlier in the process
      • Involvement of other services conducted earlier in the process
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • Workflow improvement for disposition, ancillary services, and documentation
        • Jacobson G.H.
        • McCoin N.S.
        • Lescallette R.
        • et al.
        Kaizen: a method of process improvement in the emergency department.
      • Patient sees triage nurse first, completes other processes (eg, registration) later
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Eliminating or combining steps in process
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Eliminating of outdated policies
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • New specific guidelines for “medical holds”
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Physicians and nurses encouraged to complete discharge procedures as quickly as possible
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Standardized medication storage and labeling process
        • Ben-Tovim D.I.
        • Bassham J.E.
        • Bennett D.M.
        • et al.
        Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      • New process for “pulling” patients into inpatient wards
        • Ben-Tovim D.I.
        • Bassham J.E.
        • Bennett D.M.
        • et al.
        Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      System ChangesSpecific Examples
      Data collection and monitoring
      • Daily monitoring and monthly reporting of patient and process data
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Weekly review and public posting of outcome metrics
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Performance benchmarking and feedback
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Quality improvement measurements taken and shared with staff
        • Dickson E.W.
        • Anguelov Z.
        • Bott P.
        • et al.
        The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Charts and diagrams of unit performance publicly displayed
        • Schooley J.
        No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Quarterly audits (Hospital B)
        • Dickson E.W.
        • Anguelov Z.
        • Vetterick D.
        • et al.
        Use of Lean in the emergency department: a case series of 4 hospitals.
      Education/training
      • Brief orientation to new process
        • Ben-Tovim D.I.
        • Bassham J.E.
        • Bolch D.
        • et al.
        Lean thinking across a hospital: redesigning care at the Flinders Medical Centre.
      • Training on new rapid assessment and disposition process
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Posting of process map in public areas
        • Dickson E.W.
        • Anguelov Z.
        • Bott P.
        • et al.
        The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Education day on specific areas of improvement
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Residents encouraged to attend cardiology rounds for educational reasons
        • Young T.P.
        • McClean S.I.
        A critical look at Lean thinking in healthcare.
      • Training of nurse to coordinate communications
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      Tools/technologies
      • Communication tools
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Automated telephone system
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Patient chart combining documentation from nurses and physicians
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Checklists
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Standardized forms
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Exploring new medical technology (out-of-hospital 12-lead ECG)
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • New equipment (eg, thyroid shields) and maintenance on existing equipment (eg, fixing computer order problem)
        • Jacobson G.H.
        • McCoin N.S.
        • Lescallette R.
        • et al.
        Kaizen: a method of process improvement in the emergency department.
      • Marked locations for returning equipment to right place
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • New procedure for moving charts served as a workflow-facilitating technology
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      Communication and teamwork
      • Communication tools
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Use of voicemail dictation system instead of paging
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Telephone hotline to heart investigation unit
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Communication center and dedicated nurse coordinator for communication about patient arrival, care, and disposition
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Team assessment of patient history
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • Improved communication with radiology department
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Rerouting of laboratory results to different printers
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      Staffing reassignment/new roles/new responsibilities
      • Physicians and nurses reassigned to match peak patient volume
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
        or arrival rates, generally
        • Dickson E.W.
        • Anguelov Z.
        • Bott P.
        • et al.
        The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Allocation of dedicated fast track medical and nursing staff
        • Ieraci S.
        • Digiusto E.
        • Sonntag P.
        • et al.
        Streaming by case complexity: evaluation of a model for emergency department fast track.
      • Division of medical and nursing staff to work on different patient streams
        • King D.L.
        • Ben-Tovim D.I.
        • Bassham J.
        Redesigning emergency department patient flows: application of Lean thinking to health care.
        • Kelly A.-M.
        • Bryant M.
        • Cox L.
        • et al.
        Improving emergency department efficiency by patient streaming to outcomes-based teams.
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Dedicated ECG and laboratory technician in ED
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • New screening nurse position
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • New communication specialist position
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Increased radiology staff availability on nights and weekends
        • Parks J.K.
        • Klein J.
        • Frankel H.L.
        • et al.
        Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Adding technicians and transport staff
        • Parks J.K.
        • Klein J.
        • Frankel H.L.
        • et al.
        Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      • Staff with cardiopulmonary resuscitation and automated external defibrillation skills to transport patients
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Triage nurse made responsible for determining assignment of patients to streams
        • King D.L.
        • Ben-Tovim D.I.
        • Bassham J.
        Redesigning emergency department patient flows: application of Lean thinking to health care.
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Redefined responsibilities of nurse, nursing assistant, and intake coordinator
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • Triage nurse limited to doing triage and other staff assigned to do work previously done by triage nurse (eg, checking on treatment space availability)
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Ambulatory patients encouraged to self-porter
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      Reassignment/reorganization of space
      • Dedicated spare bed
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Space reallocated for rapidly assessing and holding patients
        • Eller A.
        Rapid assessment and disposition: applying Lean in the emergency department.
      • Reorganization of ED space to create a centrally located fast track treatment area
        • Ieraci S.
        • Digiusto E.
        • Sonntag P.
        • et al.
        Streaming by case complexity: evaluation of a model for emergency department fast track.
        or 3 separate areas for different tracks
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Design of new ED space divided into 3 pods
        • Woodward G.A.
        • Godt M.G.
        • Fisher K.
        • et al.
        Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      • Dedicated express area where patients were treated sitting in chairs, not separate rooms
        • Schooley J.
        No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Use of all examination rooms
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • Redesigned staff work areas (Hospital B)
        • Dickson E.W.
        • Anguelov Z.
        • Vetterick D.
        • et al.
        Use of Lean in the emergency department: a case series of 4 hospitals.
      • Designated physician examination rooms (Hospital B)
        • Dickson E.W.
        • Anguelov Z.
        • Vetterick D.
        • et al.
        Use of Lean in the emergency department: a case series of 4 hospitals.
      • Space created for housing transport staff in ED
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Some processes (eg, registration) conducted in patient treatment area, using mobile workstations
        • Kulkarni R.G.
        A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      • Stocking of all physician-required material to the patient's right
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Reorganizing and standardizing stock carts so that commonly used items were most easily accessible
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      Other
      • Stocking conducted more on as-needed basis rather than bulk deliveries
        • Ng D.
        • Vail G.
        • Thomas S.
        • et al.
        Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      • Hallway signs to direct ambulance crew traffic
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      • Improved signs to direct patients
        • Dickson E.W.
        • Singh S.
        • Cheung D.S.
        • et al.
        Application of Lean manufacturing techniques in the emergency department.
      • “Pelvic Exam in Progress” signs
        • Jacobson G.H.
        • McCoin N.S.
        • Lescallette R.
        • et al.
        Kaizen: a method of process improvement in the emergency department.
      • Celebrations when goals achieved
        • Schooley J.
        No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Contests/incentives
        • Al Darrab A.
        • Fernandes C.M.B.
        • Velianou J.
        • et al.
        Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      Figure 3 depicts how Lean affected patient care in the studied EDs. Four trends can be seen. First, improvements were consistently reported (Figure 3). After Lean, most EDs observed reductions in length of stay, proportion of patients leaving without being seen, and waiting times. This sometimes resulted in better compliance with national standards. Second, patient outcomes often improved as well, but such improvements were rarer, and patient outcomes were less commonly measured compared with process improvements. Changes in average patient health outcomes from pre- to postLean were never measured, even though timelier care would be expected to result in better outcomes. Patient safety changes were measured in only one study, and even then only indirectly.
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bennett D.M.
      • et al.
      Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      Third, studies predominantly reported improvements, and there were few reported decrements in patient care or failures to achieve improvement. Fourth, not every study adequately reported pre- and postmetrics. In some cases, “measures of success” (eg, door-to-balloon time, door-to-needle-time) were taken but not reported.
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      In others, measures such as patient satisfaction were not described,
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      statistical tests were not used to test pre-post differences,
      • Kulkarni R.G.
      Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      or no numeric data were given to support reported changes.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      Indirect effects of Lean, those resulting from the types of process and structure changes described in Figure 3, were not consistently measured or discussed (Table 3). Some studies, however, observed that after changes were made, staff were less prone to aggression, more courteous, more satisfied with their job and less likely to leave, and faced lower workloads. Further, better utilization of staff, including more time available for supervision and education, communication improvements, (perceived) loss of autonomy because of standardization, and an increased sense of control were among reported working conditions resulting from Lean-driven changes.
      Table 3Indirect and direct effects of Lean on employees.
      StudyIndirect Effect of LeanDirect Effect of Lean
      Al Darrab et al
      • Al Darrab A.
      • Fernandes C.M.B.
      • Velianou J.
      • et al.
      Application of Lean Six Sigma for patients presenting with ST-elevation myocardial infarction: the Hamilton Health Sciences experience.
      None measured or discussedNone measured or discussed
      Ben-Tovim et al,
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bolch D.
      • et al.
      Lean thinking across a hospital: redesigning care at the Flinders Medical Centre.
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bennett D.M.
      • et al.
      Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      King et al
      • King D.L.
      • Ben-Tovim D.I.
      • Bassham J.
      Redesigning emergency department patient flows: application of Lean thinking to health care.
      • Stabilized ED staffing
      • ED regained a feeling of control
      • Decreased verbal and physical aggression, especially at triage desk
      • Standardization created by Lean a possible threat to autonomy
      • Initial reluctance but eventual acceptance of change
      • Lean sessions “created a shared awareness of how chaotic the care processes had become and generated support to change processes”
      • Possible resistance from management to a bottom-up process for discovering and solving problems
      Dickson et al
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      • Dickson E.W.
      • Singh S.
      • Cheung D.S.
      • et al.
      Application of Lean manufacturing techniques in the emergency department.
      Increase in patient-rated physician and nurse courtesy
      • With Lean, workers took on extra responsibility to improve own work, increasing workload
      • Management came to acknowledge frontline staff's superior insight into their own work process
      • Involvement in Lean led staff to accept and sustain changes
      • Staff empowered to make further suggestions for change
      Dickson et al
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      • Hospital A: Other units eager to try Lean after evidence of improvement
      • Hospital B: None measured or discussed
      • Hospital C: None measured or discussed
      • Hospital D: Increase in patient-rated physician and nurse courtesy
      • By learning about Lean and participating in Lean improvement projects, participants gain new values
      • Lean can empower workers to become designers of their own work
      • Managers may be loath to relinquish control over process design to frontline workers
      • In Hospital D, workers took ownership of the Lean process and demonstrated teamwork
      Eller
      • Eller A.
      Rapid assessment and disposition: applying Lean in the emergency department.
      None measured or discussed
      • Lean may fostered a culture of accountability
      • Lean enhanced employee engagement in process change
      Ieraci et al
      • Ieraci S.
      • Digiusto E.
      • Sonntag P.
      • et al.
      Streaming by case complexity: evaluation of a model for emergency department fast track.
      • Anecdotal improvement in work experience and job satisfaction of medical staff
      • Better use of advanced nursing staff
      • Increased time on supervision and teaching
      • Improved communication with certain inpatient units
      None measured or discussed
      Jacobson et al
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      None measured or discussed
      • New culture created as a result of Lean
      • Repeated Lean projects created positive attitudes toward future projects
      Kelly et al
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      • et al.
      Improving emergency department efficiency by patient streaming to outcomes-based teams.
      • Increase in time spent directly supervising junior medical staff
      • Staff satisfaction measured but not reported
      None measured or discussed
      Kulkarni
      • Kulkarni R.G.
      Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.
      • Kulkarni R.G.
      A reader and author respond to “Going Lean in the emergency department: a strategy for addressing emergency department overcrowding.”.
      None measured or discussedNone measured or discussed
      Ng et al
      • Ng D.
      • Vail G.
      • Thomas S.
      • et al.
      Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.
      None measured or discussed
      • Involvement in Lean led staff to better see process inefficiencies
      • Involvement in Lean led staff to accept and sustain changes
      Parks et al
      • Parks J.K.
      • Klein J.
      • Frankel H.L.
      • et al.
      Dissecting delays in trauma care using corporate Lean Six Sigma methodology.
      None measured or discussedNone measured or discussed
      Schooley
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      • Increased employee satisfaction
      • Decreased staff turnover
      • Initial resistance and opposition to changes
      • Nurses perceived more manageable workload
      • Better use of employees' skills
      • Initial concern that Lean consultant would “try to shake up the department immediately and make changes overnight”
      • Involvement in Lean led staff to accept changes
      • Staff became eager for further Lean improvements, and nurses started new improvement projects of their own initiative
      • Lean led staff to value collecting data to guide change
      • New culture created as a result of Lean
      • After Lean, some staff became more involved in shared governance
      • Lean changed leaders (eg, more focused toward continuous improvement)
      Stephens-Lee
      • Stephens-Lee C.
      Work flow analysis of admitted patients.
      None measured or discussedNone measured or discussed
      Woodward et al
      • Woodward G.A.
      • Godt M.G.
      • Fisher K.
      • et al.
      Children's hospital and regional medical center emergency department patient flow—rapid process improvement (RPI).
      None measured or discussedNone measured or discussed
      Empty circle, employee effects not measured or discussed; half-filled circle, employee effects discussed but assessed indirectly or anecdotally; filled circle, employee effects discussed based on standardized measures.
      Direct employee effects resulted from the mere presence of, and employees' participation in, the Lean initiative, quite apart from any operational changes made through Lean (Table 3). By participating in Lean sessions, process mapping, and process redesign, employees became better aware of their work and the problems therein, gained new values, and were more eager to participate in and to accept changes created by Lean. Consistent with the claims of Lean experts, some studies indeed reported that their employees became empowered to suggest future changes
      • King D.L.
      • Ben-Tovim D.I.
      • Bassham J.
      Redesigning emergency department patient flows: application of Lean thinking to health care.
      and to control the design of their own work
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      ; the high participation rates in process improvement described in one study are a testament to such empowering effects of Lean.
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      Indeed, some studies suggested that Lean may have even brought about a new participative, continuous improvement culture, leading frontline staff to take control of their own work and to participate more in shared governance.
      • Eller A.
      Rapid assessment and disposition: applying Lean in the emergency department.
      • Jacobson G.H.
      • McCoin N.S.
      • Lescallette R.
      • et al.
      Kaizen: a method of process improvement in the emergency department.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      In turn, managers learned to defer to their frontline staff and to value their input. Less commonly, the introduction of Lean was associated with at least initial resistance and concern over possible changes.
      Unfortunately, most of the employee effects described above were not systematically assessed and were either implied or based on anecdotal evidence. For example, only 1 study actually measured staff satisfaction (using surveys) and even so did not report numeric values or statistical tests.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      Given the lack of information on employee effects, it was not surprising that no study measured the relationship between Lean-related patient outcomes and employee outcomes, or the reverse. However, the authors of one study wrote, “quality improvement is intimately linked to how individual providers … interact with patients, on a day-to-day basis in the outpatient clinic and inpatient unit frontlines.”
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      Because of this vital interaction, it is possible that patient and employee outcomes influenced one another in the reviewed studies. One way that this influence might play out was suggested by another study: “Patients' irritation with delays can result in displaced anger aimed at nurses and physicians, which deflates staff morale.”
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      This suggests that reductions in delays can improve employees' quality of work life. In turn, when staff carry out improved work processes, they may exhibit increased courtesy toward patients.
      • Dickson E.W.
      • Anguelov Z.
      • Bott P.
      • et al.
      The sustainable improvement of patient flow in an emergency treatment centre using Lean.
      Only one study, Dickson et al,
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      included multiple Lean implementations across multiple EDs, and therefore only this study was able to directly address contingency factors. Dickson et al
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      wrote that “Lean is not a panacea, but rather a tool that may or may not succeed, according to the efforts surrounding its use” and more formally proposed that Lean's variable success could be understood as “context + mechanism = outcome,” in which context refers to the local context of the ED and mechanism refers to Lean.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      Based on a comparison of 4 EDs, Dickson et al
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      proposed that the 2 key contextual contingencies were (a) the involvement of frontline staff in Lean initiatives, and (b) leadership commitment to Lean. Although no other study compared EDs or hospitals (but see other comparative studies of Lean in health care
      • Miller D.
      Going Lean in Health Care.
      • Fine B.A.
      • Golden B.
      • Hannam R.
      • et al.
      Leading Lean: a Canadian healthcare leader's guide.
      ), many of the reviewed studies proposed some of the contingency factors on which their success was based (Figure 4).
      Figure thumbnail gr4
      Figure 4Contingency factors affecting success of Lean thinking efforts.*

      Discussion

      Five years have passed since the first well-publicized Lean initiatives in US health care at Virginia Mason Medical Center.
      • Nelson-Peterson D.L.
      • Leppa C.J.
      Creating an environment for caring using Lean principles of the Virginia Mason Production System.
      • Miller D.
      Going Lean in Health Care.
      • Furman C.
      Implementing a Patient Safety Alert System(TM).
      In that time, many EDs, among other health care delivery units, have begun to apply Lean as a way to fight problems such as errors, delays, and crowding. This review revealed robust opportunities for improvement in EDs and hospital-wide using Lean but also revealed considerable limitations in Lean implementations and in reports thereof.
      Lean is often characterized as a process improvement approach. Thus, not surprisingly, process change was a key component of Lean in the ED. Some process changes resembled those already advised or attempted for EDs, such as “fast-track” streaming.
      • O'Brien D.
      • Williams A.
      • Blondell K.
      • et al.
      Impact of streaming “fast track” emergency department patients.
      This is indicative of Lean's role as a philosophy and an approach to change rather than as a specific process solution.
      • Ballé M.
      • Régnier A.
      Lean as a learning system in a hospital ward.
      Perhaps this is why some EDs reported improvements with Lean but not with earlier change efforts.
      • Ben-Tovim D.I.
      • Bassham J.E.
      • Bennett D.M.
      • et al.
      Redesigning care at the Flinders Medical Centre: clinical process redesign using “Lean thinking.”.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      Process changes and accompanying protocols served to standardize care. In routine situations anticipated by protocols, standardization can be of great benefit, but safety scientists contend that overstandardization can make a system brittle and less able to adapt to unexpected variation.
      • Woods D.D.
      Escaping failures of foresight.
      Further work must investigate the extent to which individual providers and EDs as a unit can be resilient after work standardization.
      In addition to process change, work structures were modified as a result of Lean. The implication is that implementing Lean is not simply a matter of changing the way things are done. Problematic work structures are also identified and rectified through Lean, even if the focus is on process. Further, resources (eg, staffing, technology, communication) often need to be allocated to support new processes. Practitioners will need to be aware of the possibility of changing structures and not just processes, and researchers will need to measure structural changes, intended and unintended.
      Patient care typically improved as a result of Lean-driven process and structure changes, implying the possible value of Lean. One would expect improvements in length of stay, waiting times, and other commonly reported efficiency measures to be accompanied by improved patient health, fewer errors, or more appropriate care. Indeed, a recent study found a link between ED crowding and medication errors.
      • Kulstad E.B.
      • Sikka R.
      • Sweis R.T.
      • et al.
      ED overcrowding is associated with an increased frequency of medication errors.
      However, reviewed studies lacked measures of quality and safety outcome indicators, something that will need to be rectified to determine the whole effect of Lean on patients.
      • Gamm L.
      • Kash B.
      • Bolin J.
      Organizational technologies for transforming care: measures and strategies for pursuit of IOM quality aims.
      Desirable patient care effects of Lean dominate both in the presently reviewed ED literature and in Lean health care more generally.
      • Joosten T.
      • Bongers I.
      • Janssen R.
      Application of Lean thinking to health care: issues and observations.
      One reviewed ED study observed, “there is a current trend of reporting bias toward publishing positive—and more often than not immediate—results because hospitals who failed to achieve the intended behavioral changes do not come forward to openly analyze the reasons for their failure.”
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      It is possible that a publication bias, not universally positive effects of Lean, is behind the lack of null and negative results.
      • Vest J.R.
      • Gamm L.D.
      A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare.
      Full disclosure by study authors and formal inclusion of the possibility of undesirable and null effects of Lean (eg, as in Figure 2) should characterize future reports of Lean in health care. Closely related is the need for better reporting of findings, including lists of all measures with descriptions of each, numeric values (central tendency, variability), and appropriate statistical tests.
      • Vest J.R.
      • Gamm L.D.
      A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare.
      Other methodological needs are more longitudinal research,
      • Vest J.R.
      • Gamm L.D.
      A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      the use of comparison groups,
      • Vest J.R.
      • Gamm L.D.
      A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare.
      the inclusion of covariates to control for secular changes besides Lean,
      • Ieraci S.
      • Digiusto E.
      • Sonntag P.
      • et al.
      Streaming by case complexity: evaluation of a model for emergency department fast track.
      and more attention to the possibility of selection bias.
      • Dickson E.W.
      • Anguelov Z.
      • Vetterick D.
      • et al.
      Use of Lean in the emergency department: a case series of 4 hospitals.
      Employees can be affected in 2 distinct ways, indirectly and directly, but most reviewed studies tended to avoid measuring those effects or even discussing their possibility. Improving employee outcomes was not typically a goal of Lean; as one study put it, “the purpose of this Lean initiative was to improve the care of patients who visited our emergency department.”
      • Eller A.
      Rapid assessment and disposition: applying Lean in the emergency department.
      When another study found that Lean allowed senior physicians to spend more time on direct supervision, study authors referred to this as “a by-product of the initiative.”
      • Kelly A.-M.
      • Bryant M.
      • Cox L.
      • et al.
      Improving emergency department efficiency by patient streaming to outcomes-based teams.
      Only 1 study repeatedly mentioned the aim to improve employees' working conditions, and this was the only study to systematically measure changes in job satisfaction.
      • Schooley J.
      No longer waiting for answers: hospital's process changes inspire new workplace culture.
      Disregard of Lean's employee effects reveals an underestimate of the power of Lean to empower workers and to improve working conditions. The improvements listed in Table 3, although sporadic and poorly assessed, should inspire systematic attempts to achieve employee benefits of Lean. In parallel, Lean implementers and researchers should be aware that Lean can increase workload, threaten autonomy, and bring about anxiety. These undesirable employee effects are well documented in the broader Lean literature
      • Conti R.
      • Angelis J.
      • Cooper C.
      • et al.
      The effects of Lean production on worker job stress.
      • Parker S.K.
      Longitudinal effects of Lean production on employee outcomes and the mediating role of work characteristics.
      • Jackson P.R.
      • Mullarkey S.
      Lean production teams and health in garment manufacture.
      • Landsbergis P.A.
      The changing organization of work and the safety and health of working people: a commentary.
      • Landsbergis P.A.
      • Cahill J.
      • Schnall P.
      The impact of Lean production and related new systems of work organization on worker health.
      • Sprigg C.A.
      • Jackson P.R.
      Call centers as Lean service environments: job-related strain and the mediating role of work design.
      • de Treville S.
      • Antonakis J.
      Could Lean production job design be intrinsically motivating? contextual, configurational, and levels-of-analysis issues.
      • Schouteten R.
      • Benders J.
      Lean production assessed by Karasek's job demand-job control model.
      • Brown G.D.
      • O'Rourke D.
      Lean manufacturing comes to China: a case study of its impact on workplace health and safety.
      • Björkman T.
      The rationalisation movement in perspective and some ergonomic implications.
      • Koukoulaki T.
      New trends in work environment—new effects on safety.
      but may not show up in reports on Lean in health care either because of how Lean is implemented in health care or because studies in health care simply do not measure employee effects. Measures of such effects are generally available to implementers and researchers in compendia of work measures
      • Fields D.L.
      Taking the Measure of Work: A Guide to Validated Scales for Organizational Research and Diagnosis.
      National Institute for Occupational Safety and Health
      Organization of work: measurement tools for research and practice.
      and individual validated questionnaires for perceived working conditions, organizational culture, job satisfaction, empowerment, fear of job loss, and more. Additionally, implementers can devise measures—observational, surveys, interviews—that assess specific employee effects of Lean (eg, the extent to which workers think they are able to suggest or initiate changes, acceptance of Lean). Once employee effects are appropriately measured, it will be possible to assess links between employee effects and patient care effects of Lean.
      The possibility of direct employee effects, those related to “mere exposure” to Lean, is reminiscent of the Hawthorne effect, the phenomenon that change efforts bring about positive effects in workers merely because more interest is paid to the workers. Considering the Hawthorne effect can be instructive for understanding Lean in the ED in 3 ways. First, the Hawthorne effect is typically regarded as a confounder, meaning that the improvements listed in Figure 3 and those reported in other Lean studies may not be the result of better-designed work; as the spotlight on Lean fades, so may the improvements. Second, the Hawthorne effect is a nontrivial way to improve work. It inspired the Human Relations movement, which promoted paying greater attention to the human element of work, addressing workers' psychological needs, and letting workers feel involved; thus, according to the Human Relations school of thought, Lean can achieve real improvements if it is worker centered. Third, the major criticism of the Human Relations movement was that it disproportionally attempted to make workers feel special without substantially altering the design of work. Subsequent work, for example that of Sociotechnical Systems theorists and macroergonomists, demonstrated that the most successful change efforts are ones that attend to both humanistic needs and the operational needs for well-designed work. By implication, it is important to attend to both direct (“Hawthorne-like”) and indirect (“operational”) effects of Lean.
      Finally, EDs in this study differed in their characteristics and they implemented Lean in different ways. For example, studies differed in which components of Lean were implemented, the nature of worker involvement and management support, and the types of changes implemented. Further work will need to assess more closely how those context differences relate to variability in Lean's patient care and employee outcomes. Such investigations will yield a better understanding of the “critical success factors” for Lean.
      • Näslund D.
      Lean, Six Sigma and Lean sigma: fads or real process improvement methods?.
      Nine success factors, derived from this review and a broader (unpublished) review of Lean in hospitals, are hypothesized here and may be of practical value to Lean implementers (Figure 5).
      Figure thumbnail gr5
      Figure 5Practical suggestions for successful Lean implementation.
      In conclusion, Lean appears to offer significant improvement opportunities in the ED. The EDs implementing Lean in this review reported generally favorable effects (as do studies of hospital-wide initiatives including the ED, not reviewed here). However, more work remains in understanding Lean in the ED and in health care more generally, including better assessment of Lean's effects on patient safety and quality outcomes and on employees, as well as identifying the factors on which Lean's success depends. Other questions remain as well, including how Lean can best be adapted to health care, the effect of Lean on resilience, whether Lean is sustainable in the long term, whether Lean is more effective than other approaches, and the “Karen question” (after “Karen,” who seemingly single-handedly coordinated Lean improvements at Western Pennsylvania Hospital's presurgery unit
      • Spear S.J.
      Fixing health care from the inside, today.
      ): Who shall do the herculean task of coordinating the massive change effort that is Lean? In sum, much remains to be learned about this promising approach.

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      Linked Article

      • Lean Is a Tool in the Toolbox, Not the Silver Bullet
        Annals of Emergency MedicineVol. 58Issue 4
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          As we struggle to provide improved value for our patients, it is tempting to seek a single silver bullet, and Lean methodology may seem to be that bullet. Changing the complex behemoth that is American health care will require a variety of approaches. Lean is generally applied to value streams by looking for the biggest sources of waste incrementally. In a complex optimization climate, it is unlikely that an incremental approach will reach the true optimum by any measure. Indeed, systems and industrial engineers use the term suboptimization to describe less than optimal results of tuning pieces of larger systems.
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