Abstract: Assesses the safety of actively avoiding endotracheal suction in post-operative cardiac surgical patients ventilated for less than 12 hours. Describes local endotracheal suction practice, and elucidates patient experience of the endotracheal tube and endotracheal suction. Conducts an observational audit describing endotracheal sucion practice within the cardiothoracic and vascular intensive care unit in Auckland City Hospital. Undertakes a prospective, non-inferiority, randomised controlled trial investigating the safety of avoiding endotracheal suction.