Simulazione di un sistema di Pronto Soccorso

Discrete Event Simulation (DES) is an important technique to address issues related to the comparison of alternative policies in the Operation Management area and specifically in the Health Care Management. In this paper we apply DES to a sample of 22,319 patients accessing the Emergency Room (ER) of an hospital located near Milan. Based on a computerized simulation system where the arrival patient flow is independent from the activity, we created for each department a ‘control-dimission’ tree which defines the probability for a patient to go from one unit to another. The model can be represented as an oriented graph, where vertices represent the hospital units and oriented sides represent patients flow. Our results, based on 150 simulations, show that the radiology department is in overflow at a particular time of the day. Critical moments arise between 12:00 AM and 11:00 PM where the staff size is not able to manage an exponential queue line with average time service of 50’. When we consider time service as a managerial leverage and we change parameters, from 50’ to 40’ with 10’ of standard deviation, we obtain a strong reduction in the system workload. In conclusion, for complex queuing systems like ERs, there are so many random variables that it is not possible to develop analytical formulas, and consequently simulation techniques certainly represent a very useful tool to describe their operation.