1. During the first period (15 months), no protocol is used. This period consists to assess current analgesia-sedation procedure used in the pediatric intensive care unit (PICU), associated with the collection of medical and socio-demographical data about mechanical ventilation duration, sedation complications, PTSD development. The severity of pathology can be evaluated using PIM2 and POPC scores. The sedation deepness will be determined using COMFORT-B scale. Eight weeks after hospitalization, families will be phoned to assess children memories, anxious troubles, and PTSD symptoms for the patients of more than 18 months old.
2. During the transition period (6 months), nurses and physicians develop the protocol and undergo training in its use.
During the third period, a nurse-implemented sedation is used. The collected data are the same that the collected data during the first period
