Inclusion Criteria:  Eligible for inclusion children 1) <18 years; and 2) admitted to the PICU at the Centre Hospitalier Universitaire Ste-Justine (CHUSJ). To select patients at high risk for delirium, one of the following inclusion criteria will be needed: 3) mechanically ventilated patients; or 4) non-invasively ventilated patients (BiPap, Cpap or high flow nasal cannula); or 5) patients receiving opioids; or 6) patients receiving benzodiazepines.  Exclusion Criteria:  Children 1) suspected of being brain death at the time of PICU entry (Glasgow Coma Scale (GCS) 3 and loss of all brain stem reflexes); 2) with significant clinical developmental delay (based on clinical assessment and/or parental report of developmental problems that affected the child's behavior or ability to communicate; Pediatric Cerebral Performance Category ≥4); 3) planned discharge from the PICU the same or next day.