The Research Questions for this study are: 1) What are the health and functional outcomes in children affected by a critical illness, at 3 and 6 months following Pediatric Intensive Care Unit (PICU) discharge? 2) What defines poor functional recovery? 3) What are predictors of poor functional recovery in critically ill children? 4) What are the most important and relevant outcomes in critically ill children, from the patient and caregiver's point of view?