<qa>  What is the purpose of the study?This study will determine the efficacy and outcomes of protocol-directed sedation management of critically ill mechanically ventilated patients in an Australian context. The study will also improve our understanding of the patients memories and perceptions during this period, which could lead to improved clinical practices and better patient outcomes. In understanding staff perceptions of the sedation protocol and its implementation, it will assist us to identify changes to improve education for new staff and compliance issues for ongoing implementation. It may be further useful in the future development of decision-making tools and their subsequent implementation and evaluation phases. 