In this month’s workshop, Todd Roberts, System Director of Operations Improvement at MHS looked at two projects. Todd demonstrated the use of discrete event simulation modeling to analyze floor design and throughput for a new Rapid Clinical Examination provider model for a 70,000 annual visit, Level I trauma center emergency department at a 507 bed, tertiary, urban, academic medical center and flow for all aspects of architectural design proposal for $31 million dollar operating room expansion project, including pre-op admission, transport to OR, OR time, and post-anesthesia care units (PACU) for admitted and outpatient surgery.

Through the use of discrete simulation modeling, Memorial has reduced length to stay for non-admitted patients in the emergency department by 27%, reduced percentage of patients leaving by without treatment by 50%, and released admit hold time by 37% while improving patient satisfaction from the 57th to 99th percentile (Press Ganey).

In addition, Memorial has used simulation to determine the appropriate facilities layout for its new OR expansion project, determining that optimizing the flow of traffic will lead to a reduction of 30 minutes per case in wasted movement and waiting.

A recording of the May workshop will be available shortly at www.SIMUL8.com/improving_healthcare.

Sander Vermeulen, Head of Consulting for SIMUL8 Corporation said, “It’s an unique event that will bring together simulation experts and novices to connect, share knowledge, and discuss the role process simulation can play for Industrial Engineers in 2013.”

The IIE Annual Conference 2013 has a focus on applying the traditions and core concepts of industrial and systems engineering, to modern global issues. Simulation has been used by Industrial Engineers for over 20 years, but now leaders in the field will gather at SIMUL8’s event to discuss how this powerful tool can be applied to solve some of the current issues they face in their industries.

Delegates from some of the most prestigious universities in North America will be in attendance, alongside high ranking professionals from manufacturing, healthcare and business. As well as the opportunity to network, the evening will also provide panel discussions featuring some of the conference’s simulation experts, allowing their industry peers to find out more about how simulation can be used.

The event takes place from 3pm to 6pm on Saturday, May 18 in the conference hotel – the Caribe Hilton San Juan Hotel, in Puerto Rico. See you there!

Simulations are normally built using Simulation Objects (Start Points, Activities, Queues etc.) and for most simulations you can keep things quick and simple using those objects.  However, occasionally, you need an additional way to describe what happens to work items. This is where Work Item State Charts take over and allow the description of your process without having to create a series of awkward “Logical Activities”.  Work Item State Charts work independently from, or in unison with, the normal Simulation Object work item flow.

An Example:

A patient enters a hospital for a routine operation and during their stay they go though a series of stages, this is all simulated with traditional SIMUL8 Simulation Objects, but while they are in hospital there is a chance they will acquire an infection not related to their original reason for the hospital visit.

A Work Item State Chart can be used to describe and simulate the “Hospital Acquire Infection” process in parallel with the normal process:

Work item States are stored in SIMUL8 Labels. All the states shown above are stored as labels on the work items. Each label has the values 0 or 1 (shown in the Label Viewer as “No” or “Yes”). The only value a state label can have is 0 or 1.  Transitions (shown as arrows) describe how and when work items transition between states.

Create a Work Item State Chart by drawing it on the screen (drag a new state from the Work Item State Chart palette onto a simulation window. Draw arrows (transitions) between states in the same way that you draw routing arrows between Simulation Object.

If a state is drawn inside another state (for example “Not Diagnosed” is drawn above inside “Infected”) then any work item entering the enclosed state (Not Diagnosed) will automatically enter the enclosing state (Infected).

Transitions can sometimes be easier to describe by inserting a “Transition Decision” that can branch a work item change of state in a number of different directions:

Why would I use them?
Discrete Event Simulation offers you the ability to make decisions based on how items flow through your process. With State Charts you can make decisions based on the status of an item at any stage of a simulation run.

In strategic healthcare planning, you can see the ‘state’ of all individuals in your population at a glance, and make capacity and pathway decisions. You can trigger events based on a person’s state – so if they become well, they can leave hospital.

Whatever your industry, the applications of this powerful new feature are endless. This will not only simplify many of the simulations you create, they remove the need for Visual Logic to control labels. It will also open so many potential areas that you can now simulate.

For more information on the State Chart features, visit our how to guide.

The Constraining Arrivals feature on our advanced tab allows you to do this in just a few clicks! Here’s how…

Select the Start Point and navigate to the Advanced tab; here, you will see a feature for Constraints.

Start Point Constraints

Once you have this menu on screen you can choose to constrain arrivals in a number of ways.

1. Direct Use of Shifts: Select Use shift patterns directly to set up a shift for your Start Point. You can create a new shift directly from this window. If you would like to add, remove, or edit a shift, select Allocation to open the Start Point’s Shift Availability. Uncheck “Use shift patterns directly” to remove any shifts.

2. Limit the number of work items: Enter a number that you wish your Start Point to produce. For example, entering 500 here will have the Start Point produce 500 work items, and nothing more.

3. Limit the duration of arriving work items: Enter a number (in simulation time units). Once the simulation time reaches this number, the Start Point will stop generating arrivals. For example, create a simulation that is measured in minutes. Set the limit for the duration of arriving work items to 120. After 120 minutes (2 hours) of simulation time, the Start Point will stop production of arrivals.

Use them when you’re building simulations to access the spreadsheets you use most often, or when you are sharing your simulation with others to guide them to the variables you want them to adjust.

How to do it:

Navigate to the Insert Tab and select Button. This will open the Buttons List dialog.

Now you can create, delete, manage, and edit custom buttons in your simulation. Buttons are a useful tool because, once set up, they will allow you to perform actions within your simulation with only a click. This is also useful to demonstrate simulations to end users, as they may not have experience with SIMUL8, and buttons can make a simulation extremely user-friendly to someone unfamiliar with the software.

Next you need to set up your Button Properties.

Actions are the functions that buttons are commonly used for and can be easily set up with the Customizable Button feature. For Custom Dialogs, Internal Spreadsheets, Custom Reports, and Sub Processes, that these must be created within your simulation before you can create a button.

Next, select an image from file to set the look of your button. There is no set restriction for the button size, but it is generally recommended that buttons are not large graphics. You can find some ready-made button graphics in the button folder in the SIMUL8 Image Library.

Once you have created a button, open the Buttons List dialog. Select the button you want to place, and click OK. Now click anywhere within your simulation window to place the button. You can click and drag the button to move it anywhere within your simulation. It’s that easy!