Abstract for: Explaining Fundamental Emergency Department Dynamics with Simple Stock and Flow Concepts

Emergency department (ED) boarding, when patients admitted for inpatient care are forced to wait in the ED until a hospital bed is available, has been increasing. At one urban hospital, various attempts to resolve the problem have met with limited results. Boarding continues to increase and is expected to continue to do so. We build a system dynamics model of patient flow and boarder in an ED. We use data extracted from the focal hospital's electronic healthcare records to parameterize the model. We simulate scenarios to explore the simple stock and flow dynamics and to test solutions such as capacity expansion, throughput improvement, and reductions in hospital lengths of stay. Basic simulations demonstrate some of the fundamental patterns of behavior seen in the hospital, with a focus on the growing problem of boarders. Tests of the possible solutions reveal that solutions act on one part of the system, relieving some problems in one area but with concomitant exacerbation in other areas. Only when multiple solutions are implemented do we see globally desirable results. ED leaders find it challenging to communicate basic stock and flow dynamics to administrators and other stakeholders not intimately familiar with the ED. The simulation experiments done here show how basic principles of stocks and flows explain much of the problematic patters of behavior observed and provide suggestions for combining improvement initiatives to address the boarders challenge.