Thus, USC represent a milestone in the journey of patients whose condition is critical: patients from the emergency services, patients in the immediate postoperative period, coming out of intensive care patients, or finally in conventional hospitalization patients whose condition s 'worse. The creation of the USC is not subject to authorization but must be contractualized between the hospital and the Regional Health Agency (ARS) because it is resource intensive. Organizations and their operating modes are guided by the recommendations of the French Society of Anesthesia and Intensive Care (SFAR), and the Society of French Language Resuscitation (SRLF) published in 2005.The US establishment has a beneficial effect on the quality of care and the care pathway of patients at risk shown by the reduction in morbidity and mortality, the rate of admission and / or USC readmission of length of stay and hospital stay costs.