Automation Associates, Inc.

Port Huron Hospital
Identifying and addressing critical bottlenecks in healthcare systems with simulation

Challenge

Improving laboratory performance by reducing costs and enhancing patient care

Hospitals and clinics are complex operations with high variability and a web of interdependencies. In such an environment, healthcare decision makers often find it difficult to determine how to best improve patient service while reducing costs. Properly applied process improvement techniques such as lean and six sigma can yield tremendous benefits to an organization. Unfortunately, far too many organizations focus on the wrong processes, which result in wasted effort and could potentially degrade total system performance. In order to truly improve a system, attention must be focused on the correct system component based on a careful analysis of the overall system dynamic, the proposed changes, and the component’s impact on other parts of the system.

Michigan’s Port Huron Hospital (PHH) Laboratory recently began applying lean concepts to operations in order to reduce operating costs, decrease turn around times, and increase capacity. Determining the best areas to focus on for improvements proved difficult given the complex interaction of such factors as specimen arrival profiles, test mixes, analyzer characteristics, and staffing levels. The situation was further compounded by a lack of reliable process visibility and metrics. The lab wanted to avoid optimizing specific areas of the laboratory to the detriment of overall operations.

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About the Author

David Connors
Senior Analyst
Automation Associates, Inc.
615.313.7773
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Solution

Employing a simulation model to test, refine and plan for lab improvements

The PHH lab enlisted the help of Automation Associates, Inc. (AAI) to support their process improvement efforts. The team agreed that a simulation model designed to test, refine, and plan for lab modifications would help guide the process and ensure that the proposed changes would not negatively impact the lab's level of patient care. AAI built a custom simulation model that consisted of a user-friendly interface and a simulation engine built in Arena. The interface was created in Excel and enhanced with Visual Basic so that the model's inputs, execution, and analysis could be managed solely in Excel.

Multiple scenarios were run with the model in order to understand the system dynamics and interactions in the lab. The iterative analysis approach enabled the team to identify true bottlenecks that constrained the process across a wide range of conditions. Factors such as specimen volumes, staffing levels, rework percentages, and processing times were varied in order to understand and quantify their impacts on system performance. Using model results such as turn around times (TAT), analyzer and staff usage, wait (queue) times, and throughput counts, the lean team was able to prioritize improvement efforts and refine operations without undergoing a costly process of trial and error that could have put patient service at risk.

Result

Identified most efficient lab process flow to prevent bottlenecks

Model results consistently indicated that the bottleneck with the most negative impact on overall system performance was the specimen processing centrifuges. In addition to throttling the system's throughput, the centrifuges resulted in the pulsing of specimens into the testing areas of the lab. This behavior degraded overall system performance because the specimens moved through the process in spikes rather than lean flows, resulting in a cyclic pattern of capacity surpluses and shortages. This finding was critical because without addressing the centrifuge impacts, any efforts to level the flow of specimens into the lab would be negated.

The model was used to determine the ideal number of centrifuges required to reduce turn around times and avoid the specimen pulsing impact. Scenarios were run with three to seven centrifuges, with three centrifuges representing current operations and serving as a base comparison point. The results for each run were reported as a ratio of the base point. The following graph shows that adding a single centrifuge reduces average turn around times in both the specimen processing and overall lab by almost two-thirds. Each additional centrifuge offered diminished improvements to specimen turn around times, indicating that the purchase of multiple centrifuges would not be justified.

As a result of adding new centrifuges to the specimen processing area, the lean team can focus on leveling specimen arrivals and applying lean concepts such as single piece flows without having their efforts thwarted by the centrifuge bottleneck. The flexible simulation model can continue to direct and support PHH's lean improvement efforts to increase service and reduce costs.

ABOUT AAI:
Automation Associates, Inc. (AAI) is a leader in applying simulation-based analysis tools to help clients maximize investment and improve the most critical components of the global supply chain: production, distribution, transportation, and customer delivery. For more information, visit our web site at: www.AutomationAssociates.net.

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