Improving Emergency Department Processes Using Computer Simulation

Hospital Emergency Departments (ED) face different problems affecting their performance. Deficiency of inpatient beds, inability to access suitable care, noisy and overcrowded places, etc. lead to prolonged waiting time, increased length of stay and low service quality. The main purpose of this study was to improve patient flow processes in emergency departments.

The population of this descriptive- applied study included unlimited number of patients who referred to the ED of the selected hospital. Colored Petri Net was used to model patient flow processes and CPN Tools software was employed to simulate and investigate different improvement scenarios. Input data for the simulation model were obtained through timing during data collection period. Patients’ waiting time, length of stay, and resource utilization were defined as performance measures. Four improving scenarios (B, C, D, and E) were defined and their effects were investigated to improve processes.

According to simulation outputs, scenario B led to 45% decrease in waiting time for the specialists while the other scenarios had no positive (decreasing) impact on waiting time. Scenario E was the most effective one in decreasing the length of stay for patients at different ESI levels. Scenarios E and D had positive effect on resource utilization.

Selection of the best scenario depends on the mission of ED, i.e. to save patients’ life. Therefore, a scenario which is the most effective one in saving life must be chosen even if it is expensive. Although it is expensive, scenario E is preferred to scenario D due to its improved outcome. Scenario D is the second best scenario, compared to the other two scenarios, because it is less expensive.