Inpatient boarding in emergency departments: Impact on patient delays and system capacity

This study seeks insights into the impact of inpatient boarding on emergency department (ED) congestion and capacity. To do so, we model the ED as a semi-open queueing network (SOQN) with limited resources (physicians and beds) and discontinuous patient service. We present a Markov-modulated fluid queue approach to efficiently calculate service levels, and show that boarding may cause the (expensive) physician resources to be starved, especially when the bed utilization is high. While the expected number of boarding patients has a primary impact on performance, we show that there is a secondary impact stemming from the expected boarding time and the boarding probability. Boarding reduction policies perform better if they focus on reducing expected boarding time instead of the decreasing probability of boarding. Our analysis and insights are applicable also to other SOQN settings where entities require more than one resource simultaneously (e.g., intensive care units, manufacturing systems, warehousing and transportation systems).