Abstract
Emergency departments (ED) are an important front gate of the hospital with strong skill staff and helped by a high quality technical platform. After his/her arrival at the hospital, the patient follow a pathway which aims to optimize the healthcare. This patient's pathway may be slowed down or alter when there is an overcrowding of the ED, when capacities are exceeded by the number of patients to be seen, evaluated, treated, and to hospitalize. ED overcrowding is associated with many adverse effects and it is shown that the origin of this overcrowding is multifactorial. To find solutions, we must observe overcrowding in the whole of the hospital institution and of the healthcare system. The aim of this thesis is to describe the patient's pathway from his/her arrival at the ED to his/her departure, and sometimes his/her come back. Each article of this thesis represents a step of the patient's pathway. Then, the overcrowding of the ED, or of the hospital, is studied in its entirety. This collection of articles highlights the complexity of the issue and the need to mobilize the whole institution to respond.