Randomised trial comparing Baska Mask and Supreme Laryngeal Mask Airway in different head and neck positions during elective surgeries involving ASA Class I to III adults

Intervention device: Baska FESS Mask The Baska Mask 'Registered Trademark' (BM) is a third generation supraglottic airway device. It has many of the features of other supraglottic airways, with a number of innovations. These include a self-sealing membranous, variable-pressure, non-inflatable, recoiling cuff made of medical grade silicone which during positive pressure ventilation, the cuff itself is ‘inflated’ improving the seal, reducing leak and make ventilation more efficient. The BM features gastric reflux high flow suction clearance system consisting of an inlet that fits into the upper oesophagus, and the dorsal surface of the cuff is moulded to direct any oropharyngeal contents away from the glottis and towards the side channels to which suction can be attached to facilitate aspiration of this space. This system allows for rapid clearance of gastric fluids or secretions that may collect in the sump during maintenance and emergence from anesthesia which may reduce the risk of pulmonary aspiration. There is an extended hand-tab for manually curving the mask to facilitate insertion. The Baska FESS Mask is very useful in ENT apart from its usage in facial and eye surgery. It is designed to be shorter than the standard Baska Mask and is fitted with a curved connector at 120 degree angle so that when in use the device does not interfere with the surgical field and allows the surgeon to operate without interfering with his operating field. Anaesthesiologists with more than 5 years of experience in using supraglottic airways, but not necessarily the Baska FESS Mask, will perform the supraglottic airway insertions. The size of the airway will be chosen in accordance with the manufacturers’ recommendations. For the Supreme LMA, a size 3 will be used if < 50 kg, a size 4 if 50–70 kg and a size 5 if 70–100 kg Size selection of the Baska Fess will be based on the manufacturer’s recommendation of weight-based estimate ( Size 3: 30-50kg, Size 4: 50-70kg, Size 5: 70-100kg) plus clinical judgement. Both the Supreme LMA and the Baska Fess will be prepared and lubricated according to manufacturer’s guidelines. Anaesthesia will be induced with the patient’s head in the neutral position, resting on a donut head ring approximately 5cm in height. Induction will be with iv fentanyl 1-2mcg/kg and iv propofol 1.5 – 2.5mg/kg and the patient will be maintained with sevoflurane in oxygen. Depth of anaesthesia will be judged as adequate when the patient has loss of eyelash reflex and no response to jaw thrust. If coughing, gagging or movement occurs during insertion, anaesthesia can be deepened with further boluses of iv propofol 0.5mg/kg. After insertion, the cuff of the LMA Supreme will be inflated with air to attain a cuff pressure of 60 cmH2O as measured with a handheld aneroid manometer. The Baska Fess mask does not need inflation of the cuff. The different head and neck positions being investigated include the supine position, 30 degrees neck flexion, 45 degrees neck extension, 45 degrees lateral rotation to one side determined by a goniometer.