A Queuing-Base Statistical Approximation of Hospital Emergency Department Boarding

A hospital Emergency Department's(ED's) wait times can be driven by high occupancy in its downstream InPatient hospital (IP). ED patients not admitted to the IP due to high IP occupancy or transfer delays are termed to be 'boarding' in the ED. ED boarding causes a decrease in ED service capacity, longer ED wait times, increased fractions of patients that leave without treatment, and increased ambulance diversion. Boarding is a 'whole hospital' effect subject to dynamic staffing levels, demand, and capacity in a hospital. In this paper, a statistical approximation of ED boarding that has a queuing theory foundation is created and used to analyze data from a large hospital. The model produced is generic in queuing structure but specific to a hospital's data. Such approximations enable a hospital to estimate the effects of IP length of stay reduction on ED boarding and to quantify the reduction of ED waiting times where boarding is reduced or removed.