Healthcare process improvement at abdominal surgery clinic in Slovenia

Nadja Damij1, Talib Damij2, Franc Jelenc3

1Faculty of Information studies, Novo Mesto, Slovenia, [email protected] 2University of Ljubljana, Faculty of Economics, Ljubljana, Slovenia [email protected] 3 University Medical Centre, University of Ljubljana, Ljubljana, Slovenia [email protected]

Abstract

Healthcare processes in hospitals, like business processes in companies or administrative processes in governmental organizations, may accumulate problems and obstacles over time, which consequently cause the processes to become ineffective and inefficient. BPM is an approach for process modeling, improvement and automating, which has been used with great success for business process improvement. This work applies BPM for improving healthcare processes. The purpose of this work was to examine the possibility of carrying out healthcare process improvement using BPM. In order to implement BPM ideas, a revised concept of the TAD methodology was developed. As a real-life healthcare process Surgery was chosen to critically evaluate the new concept of the methodology. In this paper, the first three phases of the revised TAD methodology were introduced in a step-by-step approach, where application algorithms for each step are explained and implemented. The first phase deals with process identification, the second develops the "as- is" process model using the activity table modeling technique, and the third phase discusses process improvement by developing the "to-be" process model. Conducting this research enabled us to conclude that (a) BPM proved to be a suitable approach for carrying out healthcare process improvement; (b) the revised TAD methodology was shown to be consistent and efficient in performing process improvement; (c) the Surgery process discussed was found to be an effective and well organized but nevertheless patient stay in the clinic could be shortened, however for humane and social reasons the leadership of the clinic prefers to leave the residence time as it is; (d) the process is connected to some time-consuming activities which are executed in other departments, therefore the clinic has no influence on accelerating their execution.

Key words: Heathcare process, business process management, simulation technique, process peformance measures, TAD methodology 2

1 INTRODUCTION

Throughout the last decade, the fields of business process modeling and improvement have been gaining recognition and acceptance. The reasons for such an evolution may be found in the literature, academic publications and research studies that deal with this theme, as well as in an increasing involvement of consultancy and software development companies. Both business process modeling and business process improvement are based on the fact that a business process is the key element of the analysis of the organization. The recent literature offers various definitions of the extent of a process, process modeling, process improvement, and process management. Within this scope in mind, the process is comprehended as a transformation of inputs to outputs (Laguna, & Marklund, 2005). Furthermore, we are focusing on processes regardless of the organizational form of the research institutions (Adam, Bernik, & Rončević, 2005; Adam, & Rončević, 2003; Rončević, Makarovič, 2010). Business processes come within our scope in that they potentially add value to the organisation and as such are attracting attention (examples are given in (Martinez, et al., 2001; Aguilar-Saven, 2001; Chan, 2002; Hammer, 1990; Hammer, & Champy, 1993; Davenport, & Short, 1990). Consequently, business process modeling and improvement is on the increase as only a thorough comprehension of the business processes within the organization can lead to effective, efficient and value-adding systems. According to (Aguilar- Saven, & Olhager, 2002), it is the business processes that are the key element when integrating an enterprise. The aim of this paper is to show the possibility of using the business process management (BPM) approach to improve healthcare processes in hospitals. Management of healthcare is a crucial topic, gaining recognition in the last decade (Cooper, et al., 2011; Forsythe, 2009; Diaz, et al., 2012) and comprising with various approaches, such as using spreadsheet for simulation (Klein, & Reinhardt, 2012; Streiff, et al., 2011; Cook, 2012). Business process management is the discipline of modeling, automating, managing and optimizing business processes throughout their lifecycle to increase profitability (Khan, 2004). The present paper focuses on modeling and improvement of a healthcare process termed “Surgery” using the new concept of TAD (Tabular Application Development) methodology as a tool for implementing BPM concept. The paper is divided into 3 sections. In Sections 2 the first 3 phases of the methodology are discussed. Section 3 contains some useful remarks and findings. The final section represents the practical implication of this work. Throughout the paper, the healthcare process of carrying out surgery in the Abdominal Surgery Department (Clinic) of the University Clinical Center in Ljubljana, Slovenia, is illustrated.

2 TAD Methodology

TAD methodology consists of five phases (Damij, Damij, Grad, & Jelenc, 2008); these are process identification, process modeling, process improvement and innovation, system development, and system maintenance. Due to space limitations, the last two phases that deal with system development and system maintenance, called process management system, are not introduced. A business process management system is a generic software system that is driven by explicit process representations to coordinate the enactment of business processes (Weske, 2007). 2.1 PHASE 1 - PROCESS IDENTIFICATION

The first phase of TAD methodology consists of two steps and discusses the problem of identifying the organization’s core processes, where we do not differentiate between profit or non-profit organizations such as companies, administrative institutions, NGOs, etc. According to (Davenport, 1993), the expected number of core or major processes that pass through different functional areas of an organization may be between 10 and 20. Business processes are horizontal processes that link together the various functional activities that deliver the output of the enterprise (Watson, 1994). A business process is a flow of work passing from one person to the next, and for larger processes probably from one department to the next (Robson, & Ullah, 1996). To elaborate on the definition of a process referred to above, the following elucidations are added. A business process is related to the enterprise, as it defines the way in which the goals of the enterprise are achieved (Aguilar-Saven, 2003). A process is described by (Laguna, & Marklund, 2005) as a network of activities and buffers through which the flow units have to pass in order to be transformed from inputs to outputs. In this phase, a number of interviews are organized with the management at the strategic, business and operational levels. The purpose of the interviews with strategic management is to understand what role the organization plays and where it is heading. To accomplish this work, we try to obtain information about the strategic goals and objectives of the management. The process of organizing interviews is continued with management at the business level. The purpose of these interviews is to identify the processes of the organization. The results of these interviews are the creation of a list of selected processes and information about the departments through which each process passes. Interviews at operational level enable us is to define the flow of each of the business processes identified through various functional areas (departments). This means identification of each business process as a linkage of a set of work processes that are performed within different departments of the organization.

Surgery Process: During interviews with the management of the Abdominal Clinic one process was selected namely Surgery. This process is carried out in three departments, which are the Polyclinic, Urgent Care and Abdominal Surgery Clinic. In addition, the following goals were defined: shortening the patient’s waiting time for surgery, reducing post-surgery complications, improving patient’s hospitalization conditions at the Clinic, minimizing hospitalization time, and minimizing hospitalization costs.

2.2 PHASE 2 - PROCESS MODELING

The second phase of TAD methodology deals with developing a process model for each process selected in the previous phase. Conceptual modeling of business processes is deployed on a large scale to facilitate the development of software that supports the business processes, and to permit the analysis and re-engineering or improvement of them (Aguilar-Saven, 2003). Furthermore, business process modeling is one of the requirements of ISO 9000 international standard for quality management and assurance (Ould, 1995), as well as is one of the key questions when implementing a majority of information systems such as Workflow Management Systems, Enterprise Resource Planning and E-Business. 4

A process model consists of a set of activity models and execution constraints between them (Weske, 2007). A process model is a logical representation of a real process that describes its functioning and interactions with its environment. To sufficiently define a process, firstly the process activities and their resources need to be identified, and then the sequence order of the identified activities needs to be established. Resources are origins of supply, material assets required to activate process activities and are consequently twofold; capital assets and labour (Laguna, & Marklund, 2005). Developing a successful process model depends on appropriate selection of available modeling methods or techniques. There are many techniques or analyses used in this field, such as general process charts, process activity charts, flowcharts, dataflow diagrams, colored Petri-nets, unified modeling language and so forth. For this purpose, in this work a special modeling technique called the "Activity Table" is used. The developed Activity Table represents a model called the "as-is" process model, which describes the behavior of the process as it exists in reality.

2.2.1 Activity Table Development

The Activity Table consists of two parts. The first part (first a few columns) provides information about each activity listed by defining a number of parameters that describe the activity. The second Part is a tabular-graphical representation of the process. To develop the activity table, information about process functioning should be gained during interviews that are organized with knowledgeable employees.

Part 1

In the columns of Part 1 of the Activity Table a number of the following parameters are defined for each activity(i), where i ranges from 1 to the number of activities.  Description. A short and precise description of what exactly is the work carried out by the activity defined in row(i);  Time. The expected duration needed for activity(i) to be processed and accomplished;  Rule. One or more constraints or rules that must be satisfied in order for activity(i) to be performed;  Input/Ouput. Input(s) and ouput(s) of activity(i).

Part 2

Process: For each process, a new Activity Table is created. This table represents a model called the "as-is" process model, which describes the behavior of the process as it exists in reality. Thus, the name of the process selected is written in the first column of the Activity Table, see Table 1. If the process is large and complex, then it should be partitioned into a set of sub-processes, which are in this case listed in the second column of the Activity Table. Each process consists of a number of work processes.

Work Processes: A work process is a process that is performed within a department or organization unit. In this step all work processes of the process discussed are listed in the Work Process column of the Activity Table. For each work process listed, the name of the department in which the work process is performed, is written in the first row of the table, see Table 1. A work process is a process that consists of a set of activities. Activities: This step deals with identifying the activities performed within each of the work processes defined in the previous step. An activity is a simple micro-process that consists of one or more tasks that represent well- defined work performed by one resource. An activity may consist of a number of tasks (Damij & Damij, 2014). A task could be understood as an elementary work within an activity (Damij & Damij, 2014). To identify the activities of each work process, further interviews are organized with the employees involved in performing them. The Activity Table technique uses a small set of flowchart symbols to model a process, such as: ○, , □, ◊, →, ←, ↓, ↑.

Surgery Process: Table 1 introduces of the Activity Table of the Surgery healthcare process, which represents the process’s "as-is" model. As Table 1 shows, the process comprises 7 work processes, 54 activities, 13 resources that belong to 3 departments, and 2 external resources.

2.3 PHASE 3 - PROCESS IMPROVEMENT AND INNOVATION

Process improvement and innovation is key phase in process management, which in recent years has become a very important way of ensuring changes in order to create a competitive and successful organization. Business process improvement and innovation is closely connected with customer satisfaction. Therefore, when the customer is satisfied with the desired output of the organization, then there is probably no need for implementing changes in the organization’s way of functioning. Otherwise, the organization will discover that the customers’ dissatisfaction results in a major reduction in its profitability. When this happens then the business processes of the organization need to be improved or innovated as soon as possible. Process improvement is a complex task that may function only if it is continuously planned and implemented. Continuous business process improvement should result in a 10-15% yearly ongoing improvement in the process (Harrington, Esseling, & van Nimwegen, 1997). Otherwise, a number of problems develop over time within the process that lead to ineffectiveness of the process. Process improvement and innovation is a complex interdisciplinary problem, whose solution requires the use of knowledge from related scientific disciplines, such as process analysis, simulation, knowledge management, information systems, and others. Process improvement is done on the basis of a precise analysis of the "as-is" process model, which consequently leads to developing a "to-be" process model that is implemented in the end instead of the old process. This phase is carried out in the following three sub-phases. 6

Table 1. Activity Table 2.3.1 "as-is" Process Analysis

The aim of the first sub-phase is to examine the behavior of the "as-is" process model and identify its existing problems. If making changes in the process functioning solves the problems found, then the process improvement approach is used. Otherwise, if improvement of the process analyzed is very difficult and questionable as the process requires radical changes, then process innovation and creation of a new process is the right solution. The current sub-phase consists of four steps; these are Process Simulation, Process flow, Cycle Time Efficiency, and Process Capacity.

2.3.1.1 Process Simulation

A process may accumulate many problems that lead to its inefficiency and consequently the creation of queues within it. An effective way to improve the functionality of such a process is to use the simulation technique to discover its real functioning. Furthermore, conducting a precise analysis of the simulation results enables us to identify problems, obstacles, and difficulties in the process. A simulation is the imitation of the operation of a real-world process or system over time. A discrete system is one in which the state variable(s) changes only at discrete set of points in time (Banks, Carson, Nelson, & Nicol, 2001). Simulation is a technique that enables us to imitate the functioning of a real process by developing a process model whose attributes are the same as the attributes of the original. For this purpose, real life input data is collected and used in conducting experimentation on the overtime behavior of the model developed.

Surgery Process: Figure 1 shows a simulation model of the Surgery process, which was created on the basis of the "as-is" process model given in Table 1. The simulation of the Surgery process was run taking into consideration the assumptions listed below.  Polyclinic Infirmary - 1 patient enters the abdominal surgical infirmary every 25 minutes; - 79% of patients are registered for a first medical examination in the infirmary; - 21% of patient have a medical control after surgery; - 90% of the patients who have the first medical examination are scheduled for surgery; - The resources defined for this infirmary are 1 administrator, 1 nurse, 1 anesthetist, another department, and 2 surgeons; - Waiting for surgery is defined by the function TriangleDist(1, 14, 10), which means the minimum wait is 1, the maximum 14, and the most likely 10 days;  Urgent Care Infirmary - 1 patient enters the abdominal surgical infirmary every 60 minutes; - 25% of these patients are sent to the Clinic to carry out urgent surgery; - The resources defined in this infirmary are 1 administrator, 1 nurse, another department, and 1 surgeon;  Clinic - Patients are sent to the Clinic either from the Polyclinic or Urgent Care infirmaries; - The capacity of the Clinic is 75 beds and most of the time is completely occupied; - The number of patients hospitalized daily is equal to the number of patients that are discharged; - Prior to surgery every patient needs 1 day for internal cleansing and possible 1 day for additional medical tests; 8

- Seven resources are defined in the Clinic, these are 6 nurses, 6 nurses in Intensive Care, 2 head nurses, 8 surgeons, 1 anesthetist, and 1 administrator; - Recovery in Intensive Care is defined by the function TriangleDist(3, 5, 4), which means that the minimum stay is 3, the maximum 5, and the most likely 4 days; and - Recovery in the Clinic is defined by the function TriangleDist(4, 8, 5), which means the minimum stay is 4, the maximum 8, and the most likely 5 days. Figure 1. Simulation Model

Surgery_as-is Complete.igx

1. Yes 2. Get 3. 4. 6. 7. 5. Start Infirmary First medical appointment Register Examine Get medical Check patient Write a report check for first check patient patient findings and findings

No

15. 16. 17. No 8. 18. Register Get medical Check patient End Decide on Write a report patient findings and findings surgery Polyclinic

Yes

13. Yes 12. 11. Pre- 10. 9. False 14. Order Additional anaesthesia Pre-surgery Get date for Wait for additional tests tests patient check check hospitalization surgery No

True

26. Issue a release End Start report

No Urgent Infirmary 19. 20. 21. 22. 23. Check 24. 25. Register Patient Examine Get medical medical Decide on Send patient patient reception patient findings findings surgery Yes to clinic

33. 27. 28. 29. 30. 32. 31. Sign Confirm Patient View and Fulfill care Sign surgery Explain surgery anaesthesia surgery date reception organize documents documents documents documents

39. 38. 37. 36. 35. G 34. Place in Wake up Carry out Carry out Prepare patient at Prescribe intensive care patient surgery anaesthesia for surgery e1 medications

40. 44. 50. G In No Yes 45. 46. Cl Yes No Prescribe Check Prescribe Check at Clinic tG recovery Place in Clinic iG therapy therapy recovery e2

41. Yes 42. 47. Yes 48. 51. 43. 49. Addition- Order Addition- Order Inform about Carry out care Carry out care al tests additional tests al tests additional tests release

No No

54. Yes 53. 52. End Organize Need Prepare transport transport release report No 10

Simulation of the "as-is" model of the Surgery process (given in Figure 1) was performed using the simulation software package "iGrafx". Many interesting simulation results were obtained after running this simulation. Table 2 shows some of them, these are the minimal, average, and maximal cycle time for a patient who passes through each of the three departments of the hospital, where h means hours and d means days.

Table 2. Cycle Time

Department Min Cycle Avg Cycle Max Cycle Avg Wait Avg Work Time Time Time Polyclinic 3,13 d 8.09 d 12,74 d 7.97 d 0.12 d (2.97 h) Urgent Care 2.38 h 3.45 h 5.38 h 0.70 h 2.74 h Clinic 7.93 d 12.05 d 15.04 d 10.85 d 1.36 d

2.3.1.2 Process Flow

Process flow starts when a flow unit enters a process, continues throughout the process’s activities and buffers, and ends when it leaves the process as its output. A flow unit, job, or transaction enters a business process from its environment and goes through the different activities of the process. The flow unit on its way through the process may join other flow units at the end of one or more queues waiting to be processed by the process’s activities. To calculate the process flow, three key measures are used (Anupindi, Chopra, Deshmukh, van Mieghem, & Zemel, 2006): - The average flow time (cycle time) (T) is the average of flow times (cycle times) across all flow units that exit the process during a specific span of time; - The average inventory (I) is the number of flow units within the process boundaries at any point in time; and - The average flow rate (R) is the average number of flow units that flow through (into and out of) the process per unit of time.

Process flow is defined by the listed variables, which are calculated using Little’s law; see formula 1. Little’s law defines the important relationship between average inventory, average flow rate and average cycle time in a stable process.

Surgery Process: The abdominal surgery infirmaries are part of other departments, namely the Polyclinic and Urgent Care within the University Clinical Center. Thus, some of the information needed about the infirmaries was unavailable to us for calculating the process performance in these infirmaries. In addition to the simulation results shown in Table 2, the rest of the calculated process performance measures of the Surgery process in the Clinic are shown below. From the assumptions given in the previous section, we know that the average inventory is 75; this is the number of patients in the Clinic at any point of time. Furthermore, the simulation results showed that the average cycle time in the Clinic is 12.05 days, the minimal cycle time is 7.93, and the maximal is 15.04 days. Therefore, to calculate the flow rate (throughput) of the Surgery process, Little’s law is used as follows:

I = R * T (1) Average R = 75 / 12.05 = 6.22 patients/day 2.3.1.3 Cycle Time Efficiency

A business process is a network of connected activities and buffers with well-defined boundaries and precedence relationships, which utilize resources to transform inputs into outputs for the purpose of satisfying customer requirements (Laguna, & Marklund, 2005). A flow unit on its way from the start to the end of a process goes through a sequence of activities and buffers. Thus the cycle time of a flow unit within a process actually consists of the times spent within the process’s activities and the waiting times spent in different buffers. In order to calculate the cycle time efficiency, we first need to understand the meaning of terms such as theoretical cycle time and cycle time efficiency. Theoretical cycle time of a process is the minimum amount of time required for processing a typical flow unit without any waiting (Anupindi, Chopra, Deshmukh, van Mieghem, & Zemel, 2006). The cycle-time efficiency is the ratio between the theoretical cycle time and the average cycle time. This ratio enables us to evaluate of the waiting time in the process, which indicates the possibility of carrying out process performance improvement by reducing the waiting time in the process. The cycle time efficiency is calculated using the following formula:

Cycle Time Efficiency = Theoretical Cycle Time / Average Cycle Time (2)

Surgery Process: The average theoretical cycle time of the Surgery process is obtained from the simulation results of the "as-is" process. These results show that the average theoretical cycle time (named by iGrafx software as Avg Work) is equal to 1.36 days. Using formula 2 yields:

Cycle time efficiency = 1.36/12.05 = 11.29%

This result means that the patient waiting time is almost 88.71% of the average cycle time of the process Surgery. This is actually an expected result because by waiting time we may understand a patient’s resting or recovery time.

2.3.1.4 Process Capacity

The capacity of a process depends on the process resources that perform its activities. In order to understand the process capacity, let us define the following terms. A resource pool is a group of resources that perform similar kinds of activities. Each member of a resource pool represents a unit of this pool. The unit load of a resource is the sum of the times of the activities performed by a certain resource unit in processing a flow unit through the whole process. Capacity utilization measures the degree to which resources are effectively utilized by a process. Capacity utilization is defined for each resource pool.

Surgery Process: Table 3 shows the capacity utilization of each resource pool. The values of capacity utilizations collected in the table are obtained from of the simulation results of the "as-is" process model. 12

Table 3. Average Resource Utilization

Department Resource Resource Resource No. Name Utilization 1 Administrator 58.71% Polyclinic 1 Anesthetist 76.40% 1 Nurse 57.09% 1 Other Department 99.30% 2 Surgeon 76.02% 1 Administrator 16.67% Urgent Care 1 Nurse 5.05% Other Department 31.95% 1 Surgeon 25.09% 1 Administrator 23.00% 1 Anesthetist 24.63% 6 Nurse 39.63% Clinic 6 Nurse (Intensive care) 48.76% 2 Main Nurse 45.08% 8 Surgeon 35.30%

2.3.2 "to-be" Process Model Creation

Improvement of the existing "as-is" process is done depending on the problems identified by analyzing the simulation results and the calculated process performance measures. A number of different possibilities should be studied in order to improve the process, such as removing work processes that fit within other processes, minimizing the waiting times, shortening the times of time-consuming activities, and reducing the number of repetition loops.

Surgery Process: Analyzing the simulation results enabled us to identify the following difficulties or problems: a.1..1.a) A time consuming activity in the Polyclinic that causes days of waiting, this is the activity "Get medical findings", which is indicated by number 6, when the patient is examined the first time and by 16, when the patient returns for medical control after surgery; a.1..1.b) The same activity in Urgent Care, which is indicated by number 22, causes hours of delay; a.1..1.c) In the Clinic we found that the cycle time of the patient’s stay in the Clinic is relatively long, between 7.93 and 15.04, with an average stay of 12.05 days.

In order to find ideas for improvement of the "as-is" Surgery process, we did the following:  Firstly, we carefully analyzed Table 1 with the aim of finding redundant work processes or activities which could be removed, or where the duration of the process’s activities could be shortened. The result of this analysis was that no redundant work processes or activities exist in the Surgery process and there are no activities whose duration could be shortened;  Secondly, we tried to find solutions for the above given three problems: a) Concerning problem (a), activities 6 and 16 are performed in other departments of the hospital (Laboratory, Radiology, etc.) and therefore these activities were not accessible to our team to study the possibility of shortening them; b)The same conclusion is valid for problem (b); this is activity 22 executed in other departments and therefore not part of this project; c) Problem (c) of the relatively long stay of patients in the Clinic was discussed with the Clinic’s leadership. It was found that the recovery time could be shortened by a few days but for the following humane and social reasons the leadership prefers not to do so because: - Most of these patient are old people and have nobody to take care of them, - The majority of them have different kinds of abdominal cancer and therefore they need longer recovery times.

3 CONCLUSIONS

Implementing the first three phases of TAD methodology enabled us to identify a number of finding, such as: a)BPM is an approach that has proved in real life to be an important way to carry out healthcare process improvement successfully and is capable of keeping processes in hospitals as effective as possible. b)The proposed revised concept of TAD methodology was shown to be a consistent and efficient approach that implements process identification, modeling and improvement in an easy manner, particularly after extending its third phase by the use of the simulation technique, process performance measures, and ideas from knowledge management. c) The healthcare process discussed was found to be effective and the patients as well as the leadership and medical staff of the clinic are satisfied with it. Nevertheless, there are possibilities for further improvements such as shortening the patient’s stay in the clinic, but the leadership prefers to leave the residence time as it is. d)The Surgery process is connected to some time-consuming activities which are executed in other departments. Therefore, the clinic has no influence on accelerating their execution. Nevertheless, the leadership of the clinic has decided to take action and discuss this problem with management of those departments where these activities are executed.

References

Adam F., Bernik I., & Rončević B. (2005). A grand theory and a small social scientific community: Niklas Luhmann in Slovenia. Studies in East European Thought, 57, 1, 61-80. Adam F., & Rončević B. (2003). Social capital: recent debates and research trends. Social Science Information,42, 2, 155-183. Aguilar-Saven, R. (2001). Business process modelling techniques and tools. Department of Production Economics, WP291, Linkoping, Sweden. Aguilar-Saven, R. (2003). Business process modelling: review and framework. International Journal of Production Economics, 90, 2, 129–149. Aguilar-Saven, R., & Olhager, J. (2002). Integration of product, process and functional orientations: principles and a case study. Preprints of the International Conference on Advanced Production Management Systems, APMS, IFIP, The Netherlands. Anupindi R., Chopra S., Deshmukh D. S., van Mieghem A. J., & Zemel E. (2006). Management business process flows: principles of operations management. New Jersey: Pearson Education Inc. 14

Banks J., Carson S. J., Nelson L. B., & Nicol M. D. (2001). Discrete-event system simulation. Upper Saddle River, NJ: Prentice Hall. Chan, M. (2002). A framework to develop an enterprise information portal for contract manufacturing. International Journal of Production Economics, 75, 1–2, 113–126. Cook, D. (2012). Comparative effectiveness of technology-enhanced simulation versus other instructional methods: a systematic review and meta-analysis. The Journal of the Society for Simulation in Healthcare, 7, 5, 308-320. Cooper, J. B., et al. (2011). Design and evaluation of simulation scenarios for a program introducing patient safety, teamwork, safety Leadership, and simulation to healthcare leaders and managers. The Journal of the Society for Simulation in Healthcare, 6, 4, 231-238. Damij N., Damij T., Grad J., & Jelenc F. (2008). A methodology for business process improvement and IS development. Inf. softw. technol, 50, 1127-1141. Davenport, T. H. (1993). Process innovation: Reengineering work through information technology. Boston: Harvard Business School Press. Davenport, T. H., & Short, J. (1990). The new industrial engineering: information technology and business process redesign. Sloan Management Review, 31, 4, 11–27. Diaz, R. et al. (2012). A system dynamics model for simulating ambulatory health care demands. The Journal of the Society for Simulation in Healthcare, 7, 4, 243-250. Forsythe, L. (2009). Action research, simulation, team communication, and bringing the tacit into voice society for simulation in healthcare. The Journal of the Society for Simulation in Healthcare, 4, 3, 143-148. Hammer, M. (1990). Reengineering work: don’t automate. Obliterate. Harvard Business Review, 68, 4, 104–112. Hammer, M., & Champy, J. (1993). Reengineering the corporation, a manifesto for business revolution. New York: HarperCollins. Harrington, H. J., Esseling E., & van Nimwegen H. (1997). Business process improvement workbook. New York: McGraw-Hill. Khan, N. R., (2004). Business process management, a practical guide. Florida: Meghan- Kiffer Press. Klein, M. G., & Reinhardt, G. (2012). Emergency department patient flow simulations using spreadsheets. The Journal of the Society for Simulation in Healthcare, 7, 1, 40-47. Laguna, M., & Marklund, J. (2005). Business process modelling, simulation, and design. New Jersey: Pearson Education, Inc. Martinez, M., et al. (2001). Virtual enterprise – organisation, evolution and control. International Journal of Production Economics, 74, 1 – 3, 225–238. Ould, M. A., (1995). Business processes: modelling and analysis for re-engineering and improvement. Chichester, UK: John Wiley. Robson, M., & Ullah P. (1996). A Practical guide to business process re-engineering. Hampshire, UK: Gower Publishing Limited. Rončević, B., & Makarovič M. (2010). Towards the strategies of modern social processes. The European Journal of Social Science Research, 23, 3, 223—239. Streiff, S. et al. (2011). Leadership in medical emergencies depends on gender and personality. The Journal of the Society for Simulation in Healthcare, 6, 2, 78-83. Watson, H. G., (1994). Business systems engineering: managing breakthrough changes for productivity and profit. New York: John Wiley and Sons. Weske, M. (2007). Business process management: concepts, languages, architectures. New York: Springer.