Resource management and process change in a simplified model of the emergency department

Using a simplified model of an emergency department (ED), we illustrate a 2-step methodology for determining the optimal mix of resources (beds, clerks, triage nurses, registered nurses, and physicians) for different arrival rates. These arrival rates cover the range of annual visit volumes typically observed in EDs in the United States. We also use the model to test a widely recommended process change in EDs: bedside registration. Rather than perform registration immediately after triage, registration is now performed only after the patient is placed in an ED bed and assessed by a nurse and physician. Our results show that bedside registration is efficient only when sufficient beds are available; when an ED is crowded and bed availability is low it actually leads to an increased length of stay. We view our model as a first step in the development of a more elaborate, multiple-acuity ED model.