Demand for hospital emergency departments: a conceptual understanding.

BACKGROUND: Emergency departments (EDs) are critical to the management of acute illness and injury, and the provision of health system access. However, EDs have become increasingly congested due to increased demand, increased complexity of care and blocked access to ongoing care (access block). Congestion has clinical and organisational implications. This paper aims to describe the factors that appear to influence demand for ED services, and their interrelationships as the basis for further research into the role of private hospital EDs.