Table 2.

Descriptive results in implementing lean in hospitals’ emergency units

Au-Cu-Ye	model	Lean implementation Length of time (month)	Methods	Project Team Composition	Indicator	results
Vermeulen et al., [31]	Lean Process	7	before and after	senior leaders, managers, and staff from a variety of  departments	Length of Stay	Both 90th percentile and median ED length of stay and time to physician assessment were significantly lower after the program
Naik et al., [32]	lean principles	18	before and after	members of departmentalleadership and key stakeholders relatedto ED administration (e.g., finance and hospitaloperations)	median ED patient visits, median login to disposition time, median login to triage time, Provider productivity	ED patient visits per month rose 7.3%, median login to disposition time declined from 4.6 hr to 4.0 hr. median login to triage time decreased from 0.6 hr  to 0.3 hr. Provider productivity improved by 18.8%
McCulloch et al., [25]	lean principles	8	Interrupted time series	Academic expert in Lean, two members of a consultancy specializing in Lean improvement techniques, senior and junior surgeons, and a human factors expert.	Correct administration of prophylaxis for deep vein thrombosis, Correct use of venous site infection protocol, direct verbal communication between medical and nursing teams on daily rounds, Adequate monitoring of patients’ vital signs and recording of their risk scores, Patients without a drug prescribing error	Compliance with the five process measures targeted for Lean intervention ) but not the two that were not) improved significantly (relative improvement 28% to 149%; P<0.007)
Mazzocato et al., [30]	lean thinking	1	before and after	Physician, nurse, hospital management team	waiting and lead times	Improvements in waiting and lead times (19-24%)
Sanders JH & Karr T. [33]	Lean Six Sigma	-	Cross-sectional, case study	ED registered nurses (RNs), Hematology and Chemistry Lab personnel, and process improvement team members	turn-around-times	30 percent decrease in complete blood count analysis (CBCA) Median TAT, a 50 percent decrease in CBCA TAT Variation, a 10 percent decrease in Troponin TAT Variation, a 18.2 percent decrease in URPN TAT Variation, and a 2-5 minute decrease in ED registered nurses rainbow draw time
Chan et al., [34]	Lean techniques	10	before-and-after study	-	Triage waiting time, consultation waiting time, blood result time, admission waiting time, total processing time and ED length of stay	The triage waiting time and end waiting time for consultation were significantly decreased. The admission waiting time of emergency medical ward (EMW) was significantly decreased from 54.76 minutes to 24.45 minutes after implementation of PAT program (P<0.05).
Niemeijer et al., [27]	Lean Six Sigma	2	before-and-after study	-	length of stay (LOS)	The average LOS of trauma patients at the TND at the beginning of the project was 10.4 days. After the implementation of the improvements, the average LOS was 8.5 days
Dickson et al., [35]	Lean	-	before-and-after study	Frontline workers, ED management,	length of stay, patient volume, patient satisfaction	One year post-Lean, length of stay was reduced in 3 of the EDs despite an increase in patient volume in all 4. Each observed an increase of patient satisfaction lagging behind by at least a year
Ng et al., [36]	Lean principles of the Toyota Production System	12	before-and-after study	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	mean registration to physician time, patients who left without being, length of stay	The mean registration to physician time has decreased from 111 minutes to 78 minutes. The number of patients who left without being seen has decreased from 7.1% to 4.3%. The length of stay (LOS) for discharged patients has decreased from a mean of 3.6 to 2.8 hours, an improvement in ED patient satisfaction scores.
Tejedor-Panchón et al., [37]	lean methods		before-and-after study		patient's time spent in the examination area of the department, wait time before the first visit by a physician, and the percentage of patients who left before being seen	The mean (95% CI) time spent in the examining areas by patients with the simplest emergencies was reduced from 80.4 (75.3-85.6) minutes to 61.6 (57.7-65.5) minutes (P<.001). Mean (SD) delays until first contact with a physician were also reduced significantly (P<.001) from 58.0 (6.3) minutes to 49.1 (3.7) minutes. The percentage of patients leaving before seeing a physician also decreased, from 2.8% (0.5%) to 2.0% (0.9%) (P<.001).
USA, 2013[38]	lean techniques		before-and-after study	-	Daily visits, patient satisfaction.	daily visits to the ED have increased from 42 to 54, and patient satisfaction scores have jumped 25 points on Press Ganey surveys
USA, 2012[39]	lean techniques		before-and-after study	-	patient volume	patient volume is up by about 25% at all three hospitals
Dickson et al., [40]	lean manufacturing techniques	12	before-and-after study	2 ED physicians, 2 EDnurses, an ED physician assistant, 2 non-ED physicians , 2 radiology technicians, a laboratory technician, 5industrial engineers, and 5 external participants from alocal business council	patient satisfaction, expense per patient, ED lengthof stay (LOS), and patient volume	Patient visits increased by 9.23% in 2006. Despite this increase, LOS decreased slightly and patient satisfaction increased significantly without raising the inflation adjusted cost per patient
Piggott et al., [41]	Lean principles	10	before-and-after study	senior management, external Lean consultants, emergency administrators, nurses, physicians, residents, porters	proportions of care milestones (first electrocardiogram [ECG], ECG interpretation, physician assessment, and acetylsalicylic acid [ASA] administration) meeting target times	The proportion of cases with 12-lead ECGs completed within 10 minutes of patient triage increased by 37.4% (p, 0.0001). The proportion of cases with physician assessment initiated within 60 minutes increased by 12.1% (p 5 0.0251). Times to ECG, physician assessment, and ASA administration also continued to improve significantly over time (p values , 0.0001).
Murrell et al., [42]	Lean principles	6	before-and-after study	Physician, nurse	ED length of stay, ED arrival to physician start time, ED without being seen by a doctor (LWBS)	ED length of stay was longer in the period before Rapid Triage and Treatment (RTT) than after.  Mean ED arrival to physician start time was 62.2 minutes prior to RTT and 41.9 minutes after. The LWBS rate for the six months prior to RTT was 4.5% and 1.5% after RTT initiation.
El Sayed et al., [43]	Lean Methodology	20	before-and-after study	ED chairperson, the ED medical director, 2 nurses including the ED nurse manager, case management, clerks, and registration staff	door to doctor time, Length of stay	There was a statistically significant decrease in the mean door to doctor time. Length of stay of both admitted and discharged patients dropped from 2.6 to 2.0 hours and 9.0 to 5.5 hours
Kane et al., [44]	Lean Manufacturing techniques	-	before-and-after study	Physician, nursing leadership, operational leaders, performance excellence consultants	waiting time, length of stay, patient throughput, patient satisfaction	decreased patients’ wait times and length of stay, while improving patient throughput and reported satisfaction
Eller [45]	lean tools	18	Cross-sectional	Staff members	LWBS, LOS, diversion time	reducing the average length of stay for all emergency department patients by 45 minutes, diversion by 55%, and patients who left without being seen by 28%
King et al., [46]	Lean Thinking	-	before-and-after study	patient care assistants, clerical staff, junior and senior nursing, medical staff	waiting times, total durations of stay in the ED	All groups of patients spent significantly less overall time in the department and the average number of patients in the ED at any time decreased
Richardson et al., [29]	Lean Methodology	40	before-and-after study	Nurses	nursing time in obtaining needed supplies in an ED	significantly decreases the number of searches by nurses for supplies
White et al., [47]	Lean	6	controlled before-and-after	-	LOS, percent of patients discharged within one hour, time in exam room	Median LOS among discharged patients was reduced by 15 minutes. The number of patients discharged in <1 hr increased by 2.8%. Median exam room time decreased by 34 minutes.
Damato and Rickard [48]	Lean-Six Sigma	4	before-and-after study	-	Hemolysis	ECC hemolysis decreased by 91%— from 9.8% to 0.88%. Housewide hemolysis decreased by 59%—from 3.4% to 1.39%.
Dickson et al., [49]	Lean	24	Cross-sectional	2 ED physicians, 2 EDnurses, an ED physician assistant, 2 non-ED physicians , 2 radiology technicians, a laboratory technician, 5industrial engineers, and 5 external participants from alocal business council	LOS, expense per patient, patient satisfaction	Total length of stay has decreased 3%. 9% decrease in the direct expense per patient. 9% increase in patient satisfaction