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.

Inclusion Criteria:

1. Adult patient, age >18 and <80
2. Undergoing anesthesiologist-administered sedation for diagnostic/ therapeutic procedures

Exclusion Criteria:

1. Expected procedure require access to or involve the nostrils.
2. Obesity (BMI >=30)
3. Chronic lung diseases (e.g. COPD) associated with chronic hypoxia
4. Pregnant or lactating women.
5. Known chronic liver or renal disease.
6. Mentally incapable of providing informed consent

Patients undergoing anesthesiologist-administered sedation for diagnostic/ therapeutic procedures