Developing model requirements for patient flow simulation studies using the Unified Modelling Language (UML)

Health care systems are known to be complex and difficult to analyse. Unified Modelling Language (UML) tools have been extensively used to analyse complex systems in several domains, including health care. However, the utility of UML tools in the mapping of care processes has not been demonstrated. This paper reports on the findings of a project that employed UML tools to map the entire care process for patients presenting with symptoms of fractured neck of femur to an acute care hospital in the UK. We employed the UML activity diagram to capture the sequence and conditions of the progress of patients through care activities from a care-system perspective, use case to detail the function performed by each care activity depicted in the activity diagram, and use UML state diagram to capture the dynamic behaviour of patients by depicting states and transition specifications from a patient's perspective. We argue that UML tools can be beneficially employed in the mapping of care processes and to create an information library with the results of such mapping. We also argue that the process mapping method presented here can be used as a basis to develop requirements for simulation models of the flow of patients through the care process.