Patients under sedation not uncommonly develop upper airway obstruction or other respiratory complications and no airway device is available to provide reliable maintenance of the airway at present. I believe the YO2(R)airway catheter can improve the maintenance of patent airway in most sedated patients and improve O2 delivery to the airway. In addition it may also greatly facilitate the monitoring of expired CO2, which is widely recognised as the most important monitor of adequacy of breathing, yet frequently impossible to perform satisfactorily in sedated patients at the moment.