The Emergency Department (ED), now recognized as an essential part of public health service, has developed rapidly since its founding 40 years ago. It is one of the core care units of any hospital globally, providing 24-hour service. As the services offered by EDs increase and the management process becomes more complicated, patients stay in EDs for longer, and EDs become more crowded [1]. On the other hand, the service given by the hospital's emergency department is highly manifested in the quality of care and significantly influences the hospital's public image [1].

Emergency medicine is the medical specialty that links primary care and specialist care to treat unexpected illnesses and injuries. Therefore, it must be available 24 h a day as an essential component of a healthcare system. In this work environment, emergency department (ED)staff face unique challenges such as treating patients arriving at the department with dynamic and unexpected states of illness, dealing with uncertainty regarding patient medical histories, and the need for time-dependent and triage-based decisions making [2].

Emergency department (ED) crowding has been described as the most severe problem that endangers the reliability of the health care system worldwide [3]. It has been reported to cause diagnosis, delays in treatment, decreased quality of care, and poor patient outcomes [4].

According to the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), over one-half of all “sentinel event” cases of morbidity and mortality secondary to delays in treatment occur in hospital EDs, and ED crowding has been cited as a contributing factor in 31 % of these cases [5]. The actual causes of ED crowding are much more complex [3], [5] and include inadequate inpatient bed capacity, higher severity of illness, and hospital system restructuring. Hospital bed shortages have been studied as factors that potentially affect crowding. Non-availability of ED beds because they are occupied by admitted patients waiting for transfer from the ED to inpatient units restricts ED's capacity to accept new arrivals and consumes Ed's resources [6].