title: A flexible simulation platform to quantify and manage emergency department crowding.
abstract: BACKGROUND
  Hospital-based Emergency Departments are struggling to provide timely care to a steadily increasing number of unscheduled ED visits. Dwindling compensation and rising ED closures dictate that meeting this challenge demands greater operational efficiency.
  
  
  METHODS
  Using techniques from operations research theory, as well as a novel event-driven algorithm for processing priority queues, we developed a flexible simulation platform for hospital-based EDs. We tuned the parameters of the system to mimic U.S. nationally average and average academic hospital-based ED performance metrics and are able to assess a variety of patient flow outcomes including patient door-to-event times, propensity to leave without being seen, ED occupancy level, and dynamic staffing and resource use.
  
  
  RESULTS
  The causes of ED crowding are variable and require site-specific solutions. For example, in a nationally average ED environment, provider availability is a surprising, but persistent bottleneck in patient flow. As a result, resources expended in reducing boarding times may not have the expected impact on patient throughput. On the other hand, reallocating resources into alternate care pathways can dramatically expedite care for lower acuity patients without delaying care for higher acuity patients. In an average academic ED environment, bed availability is the primary bottleneck in patient flow. Consequently, adjustments to provider scheduling have a limited effect on the timeliness of care delivery, while shorter boarding times significantly reduce crowding. An online version of the simulation platform is available at http://spark.rstudio.com/klopiano/EDsimulation/.
  
  
  CONCLUSIONS
  In building this robust simulation framework, we have created a novel decision-support tool that ED and hospital managers can use to quantify the impact of proposed changes to patient flow prior to implementation.
authors.affiliation: Department of Mathematics, University of Florida, Gainesville FL, USA. jehurwitz@ufl.edu.
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Hurwitz
authors.forename: Jo Ann
authors.initials: JA
authors.lastname: Lee
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Lopiano
authors.forename: Scott A
authors.initials: SA
authors.lastname: McKinley
authors.forename: James
authors.initials: J
authors.lastname: Keesling
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Tyndall
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003441:Crowding; D004636:Emergency Service, Hospital / Q000458:organization & administration* / Q000592:standards; D006801:Humans; D013997:Time Factors