Proceedings of the 2018 Winter Simulation Conference M. Rabe, A.A. Juan, N. Mustafee, A. Skoogh, S. Jain, and B. Johansson, eds. ANALYSING THE ED PATIENT FLOW MANAGEMENT PROBLEM BY USING ACCUMULATING PRIORITY QUEUES AND SIMULATION-BASED OPTIMIZATION Marta Cildoz Fermin Mallor Amaia Ibarra Institute of Smart Cities (ISC) Emergency Department Public University of Navarre Navarre Hospital Compound Campus Arrosadia Irunlarrea-Str. 3 Pamplona, 31006, SPAIN Pamplona, 31008, SPAIN ABSTRACT This paper deals with the Emergency Department (ED) patient flow management problem. After triage, where acuity of patient’s illness is assessed, each patient waits for treatment. Different care requires disparate resources, leading to different care-paths in the ED. During treatment patients can be in a diversity of treatment stages (waiting for the first consultation, doing clinical tests, waiting for a second consultation, etc.). Therefore, the selection of the next patient to be seen by a physician is not trivial, especially when there are different quality goals to be attained simultaneously. This research investigates disciplines based on accumulation of priority while waiting (APQ). Pure priority disciplines are independent of the quality goals set for the ED while the new ones can be optimized to achieve those goals as much as possible. The optimal APQ policies are obtained by using simulation-based optimization. Both types of policies are tested in a real case. 1 INTRODUCTION Growth in utilization of emergency care is observed in high income countries. For instance, in the US, emergency admissions grew over 50 per cent from 1992 to 2006 (Schuur and Venkatesh 2012) and 9,3% from 2014 to 2017 in England (NHS England 2018) mainly due to its ageing population who are the main consumers of healthcare services. Some studies quantify that this factor itself can explain 40-50 per cent of the total growth (Tang et al. 2010; Strunk et al. 2006). This trend is expected to continue in the near future. Accordingly, emergency medicine represents a large share of health care spending, which could be as high as 10%, according to Lee et al. (2013). Nevertheless the expenditure in health care does not follow the demand growth pace, being stabilized in the last years around 10% of GDP (see Figure 1). Thus the mixture of a growing demand and a quite stable capacity of service lead to every time overcrowded emergency departments (ED) and makes operational health care management even more critical and important to guaranty the quality and universality of the public health care services. This paper uses a quantitative approach to improve the management of the patient flow in an ED. EDs are especially difficult to manage: they evolve in a high stochastic environment due to the variability in the patient arrival rate, illness severity, and in general, health resources needed for treatment (material and human). This chaotic, stressful, and unpredictable environment makes difficult to find an optimal strategy for the patient flow management. Just after triage, in some EDs, patients are assigned to one of the physicians working at that shift, who decides the order in which patients receive the treatment, while in other EDs patients made up a single queue from which physicians pick up the next patient. In both situations the physicians have to manage the portfolio of pending patients taking into account their level of severity. In addition, pending patients can be in different stages of their treatment: waiting for the first consultation, waiting or doing clinical diagnostic tests, waiting for second consultation or waiting to 2107 978-1-5386-6572-5/18/$31.00 ©2018 IEEE