At Cincinnati Children’s, we have committed to maximizing utilization of existing facilities so that critical resources can be used for improving patient care and outcomes. Building new beds without first optimizing use of the ones you have is not only expensive, it is not compatible with the present healthcare environment. We have found that simulation modeling helps us to achieve our goals.
The use of simulation modeling to predict our program growth allows us to not only forecast our bed needs but to determine longer-term resource demands. Our modeling helps predict our needs relative to training, recruitment and equipment. It can also help us determine what impact predicted changes will have on institutionally shared resources such as radiology, consult services and ICUs.
Why Use Models?
Simulation modeling is a tool used in many industries, such as banking, travel and manufacturing, to identify resource needs and to test the effectiveness of planned improvements before implementation. Simulation, in general, is the imitation of a real environment or process so that a model represents the characteristics or behaviors of the system. Using data collected in the area of interest, we develop mathematical representations of the time and variability that naturally occur in the environment. A computerized model uses the mathematical formulas along with data and rules for the system, allowing us to mimic the area that we want to assess. Assessment of change in the model allows for analysis of performance improvements before they affect patients and staff, and provides quantitative estimates for changes before deployment (i.e., understanding whether changes have a positive, negative or neutral influence on the system).
Once we’ve built a good representation of the current system, we can begin to modify the rules and / or data to ask questions about how specific changes might impact the system. An example might be a model of the ED that “knows” rates of patient arrival relative to time of day and factors in existing staffing and resource levels. The model would be given rules about the duration and resource needs associated with specific activities, which would allow the user to run simulations to measure the impact of changes to the existing system (whether adding another nurse results in lower wait times; whether the cost of adding the nurse is covered by the increased patient volume).
When to Use Simulations?
Simulation models, rather than theoretical / mathematical models, are best used with systems that change with time and involve randomness. Modeling complex dynamic systems theoretically often requires too many simplifications, and the emerging models may not be valid.
How is Simulation Performed?
Simulations may be performed manually. Most often, however, the system model is written either as a computer program or as input into simulator software.
Development of a computer model is typically performed by a trained resource and requires:
- An understanding of the problem to be solved
- Data collection and analysis
- Process flow analysis
- Model development
- Input and output analysis
- Model validation, verification and calibration
We first applied modeling to understanding unplanned ICU bed demand and found that doing so offered unique insights and information that would be difficult to secure in any other way. Since that project, we have used simulation to explore demand in other inpatient units, outpatient clinics, emergency rooms and even to assess disease progression so that we could appropriately focus our research efforts. Cincinnati Children’s is one of only a few hospitals that have dedicated resources to utilize this and other modeling tools, and we remain dedicated to using the best methods available to manage our capacity and ensure seamless patient flow through the system.