Almost all critically ill children who are mechanically ventilated require sedation and analgesia. Providing effective sedation for children in the PICU requires careful balancing of the need for sedation with the adverse effects associated with sedative medications. Inadequate sedation may result in undue pain and suffering for children, ventilator dysynchrony and may risk removal of life sustaining devices. Excess sedation limits patients' interaction with their parents and care-givers and may result in delayed weaning from mechanical ventilation, prolonged PICU stay and the attendant risks of increased morbidity. Critically ill children may also experience withdrawal when these medications are stopped. Randomized trails in adults have shown that sedation related interventions can improve patients outcomes, but such trials have not been performed in children.