Impact on Delirium of the Use of DEXmedetomidine as First-line Sedation in PEDIAtric Intensive Care

The goal of this clinical trial is to learn if dexmedetomidine can reduce delirium in critically ill children, needing mechanical ventilation for more than 12 hours. The main question it aims to answer is : • Does dexmedetomidine reduce the proportion of children presenting at least one episode of delirium during their intensive care unit (ICU) stay ? Researchers will compare dexmetomidine to midazolam, to see if the use of dexmedetomidine reduces the prevalence of delirium. Participants will be sedated with midazolam or dexmedetomidine, according to randomization arm, and the rest of sedation is determined by the study protocol.