Abstract
Emergency Department(ED) crowding, a consequence of simultaneous increasing demand for health care and a deficit in available hospital beds and ED beds, has become an increasingly significant public health problem. One way to solve this problem is to decrease the boarding time of emergency patients, but the amount becoming a limitation factor as the demand is growing rapidly. When the number of emergency patients increases over the allocation of manpower and equipment, emergency is likely to be overloaded. Such a situation might crowd out the resources for critical patients, seriously affect the emergency service quality, and reduce the morale of staff before the patients being safe. In this research，a discrete-event simulation approach was used to model Emergency Department’s (ED) patient flow to investigate the effect of inpatient boarding on the ED efficiency in terms of the National Emergency Department Overcrowding Scale(NEDOCS) score. The decision variable in this model was the short stay units, defined as the number of beds in short stay room designed for the least patients. Our analysis shows that the Overcrowded+ (a NEDOCS score over 100) ratio decreased 6-22% when the short stay units changed from 9 to 15.