Simulating an emergency department: the importance of modeling the interactions between physicians and delegates in a discrete event simulation

Abstract

BackgroundComputer simulation studies of the emergency department (ED) are often patient driven and consider the physician as a human resource whose primary activity is interacting directly with the patient. In many EDs, physicians supervise delegates such as residents, physician assistants and nurse practitioners each with different skill sets and levels of independence. The purpose of this study is to present an alternative approach where physicians and their delegates in the ED are modeled as interacting pseudo-agents in a discrete event simulation (DES) and to compare it with the traditional approach ignoring such interactions.MethodsThe new approach models a hierarchy of heterogeneous interacting pseudo-agents in a DES, where pseudo-agents are entities with embedded decision logic. The pseudo-agents represent a physician and delegate, where the physician plays a senior role to the delegate (i.e. treats high acuity patients and acts as a consult for the delegate). A simple model without the complexity of the ED is first created in order to validate the building blocks (programming) used to create the pseudo-agents and their interaction (i.e. consultation). Following validation, the new approach is implemented in an ED model using data from an Ontario hospital. Outputs from this model are compared with outputs from the ED model without the interacting pseudo-agents. They are compared based on physician and delegate utilization, patient waiting time for treatment, and average length of stay. Additionally, we conduct sensitivity analyses on key parameters in the model.ResultsIn the hospital ED model, comparisons between the approach with interaction and without showed physician utilization increase from 23% to 41% and delegate utilization increase from 56% to 71%. Results show statistically significant mean time differences for low acuity patients between models. Interaction time between physician and delegate results in increased ED length of stay and longer waits for beds.ConclusionThis example shows the importance of accurately modeling physician relationships and the roles in which they treat patients. Neglecting these relationships could lead to inefficient resource allocation due to inaccurate estimates of physician and delegate time spent on patient related activities and length of stay.

A preliminary study of a novel emergency department nursing triage simulation for research applications

“…Having an experimenter in another room read scripted patient responses to produce a “virtualized” verbal interaction is one cost-effective approach to improving patient-subject interactions. Future models should also address the diversity of clinicians in the ED, the hierarchy of their skills, delegation to other providers, prioritization of tasks, and provider tasks such as teaching and administrative work, or the presence of trainees, who generally slow patient throughput [10]. We are currently modifying the platform to allow us to study interactions of groups of subjects as well as more robust graphics, in a manner that might be useful to institutions that lack computers with sufficient graphics capability or that have firewalls that make accessing servers and downloading more robust programs difficult.…”

“…The most frequently used computerized ED model of emergency department patient flow is discrete event simulation (DES) [10], which is used to predict the effects of operational changes on patient throughput, waiting times, efficiency, length of stay, resource utilization and interaction of processes within a system [10, 12, 13]. An extension of DES is agent based modeling (ABM), which models behavior and its outcomes at the individual level [10].…”

“…An extension of DES is agent based modeling (ABM), which models behavior and its outcomes at the individual level [10]. A model using novel software to create a hierarchy of heterogeneous pseudo-agents has been used to represent patients moving through the emergency department during triage, evaluation by a physician, diagnostics, and treatment [10]. The main use of this model has been to develop optimal staffing models for different patient populations.…”

Individual versus integrated simulation techniques in healthcare applications

“…In 2013, Morgan, et al [14] demonstrated the importance of modeling the interactions between physicians and delegates with a DES model of an emergency department. The physicians and their delegates were modeled as interacting pseudo-agents in the discrete event simulation model.…”

“…Many works demonstrated the feasibility of integrated approaches in healthcare. Most of the integrated models have combined DES and SD techniques [15], [16], [17], [20] and [21] while some other works [14] and [19] have combined DES and ABS approaches and [18] has combine ABS and SD approaches.…”