Laryngeal Mask Airway Flexible (LMA Flexible) is useful in various surgery because of its unique design. The flexometallic tube allows it could be used in head and neck related surgery but also make insertion more difficult. The ideal position of LMA Flexible is important because in most case, the surgery requiring LMA Flexible allows movements of the stem or patient's head during operation without dislodgement of LMA Flexible. Several studies have examined different techniques like assisting LMA Flexible with rigid introducers or lifting epiglottis with direct laryngoscope. But there is no study using videolaryngoscope (VL) for LMA Flexible insertion. The investigator hypothesized that McGrath(McGRATH™ MAC video laryngoscope;Aircraft Medical Ltd, UK.), one kind of the VL, assisted insertion would increase the success rate of LMA Flexible insertion by lifting epiglottis and securing a view while LMA Flexible is seated. The aim of this study was to investigate the efficacy of the McGrath VL assisted insertion of LMA Flexible compared with the standard method of digital manipulation technique in regard to the ideal anatomical position and sealing pressure in anesthetized adult patients.

Inclusion Criteria:

• ASA (American society of anesthesiologist) physical status classification system I and II,
• scheduled to elective general anesthesia with the use of LMA

Exclusion Criteria:

• suspected difficult airway
• a history of a recent upper airway tract infection
• gastroesophageal reflux
• body mass index > 30 kg/m2