Comparison of 'Low Skill Fibreoptic Tracheal Intubation' Via I-gel® and Air-Q® Supraglottic Airway Devices in Patients With Simulated Difficult Airways.

The investigators are testing to see if fibreoptic intubation in patients via a supraglottic airway device i.e. 'low skill fibreoptic intubation' (LSFOI) is more successful via the i-gel® than in the air-Q®. Patients are those scheduled for elective surgery under general anaesthesia who would normally require tracheal intubation. The investigator's hypothesis is based on the results of the investigator's recent manikin study (CIRB 2014/2039). The investigators would like to see if this hypothesis translates to patients. It will also test secondary outcomes e.g. SGD insertion success rates and times, and intubation times. In the aforementioned manikin study, the air-Q® performed better with the SGD insertion rates and times. However, the i-gel® performed better with intubation success rates and times. The devices may perform different due to differences between the devices: design (shape, volume, length, aperture), material composition, and technique required for insertion and intubation.

24 adult patients undergoing elective surgery requiring general anaesthesia and endotracheal intubation in the major operating theater of Singapore General Hospital will be enrolled. The patient will then be randomised in equal proportions into two groups, either the air-Q® or i-gel®. Patients will undergo induction of general anaesthesia in a standardised fashion and in accordance with usual practice in the investigator's department of anaesthesia. Intubation will then proceed with the assigned airway device. Data collected will include successful endotracheal intubation, as evidenced by the presence of end tidal carbon dioxide on a capnograph. Time to intubation (from the initial handling of the airway device until successful intubation is confirmed with successful lung ventilation), the number of attempts required and the view achieved (according to the modified Cormack and Lehane scoring system) will also be recorded. Injuries to the lips, teeth or upper airway will be sought and documented by a blinded observer in the Post Anesthetic Care Unit.

A protocol will be provided to standardise the induction of general anaesthesia. This will involve the application of standard patient monitors, a period of pre-oxygenation, and administration of anaesthetic agents and muscle relaxants. If the patient desaturates to SpO2 < 94% during intubation, the intubation attempt via either the air-Q® or i-gel® will be abandoned and intubation will proceed using the conventional direct laryngoscope.