The Pentax-AWS_ system (AWS; Pentax Corporation, Tokyo, Japan) is a new rigid indirect laryngoscope which has an integrated tube passage function. Pentax-AWS improved the laryngeal view and facilitated tracheal intubation in patients with restricted neck motion. The purpose of this clinical trial was to evaluate the relative efficacy of the AWS laryngoscopes when used by experienced anesthetists in Obstructive Sleep Apnea Syndrome (OSAS) patients and to compare its performance with the Macintosh laryngoscope.

The occurrence of difficult intubation in OSAS patients is higher than in age and sex matched control patients. The Pentax-AWS_ system (AWS; Pentax Corporation, Tokyo, Japan) is a new rigid indirect laryngoscope which has an integrated tube passage function. Several studies reported that Pentax-AWS improved the laryngeal view and guide also facilitated rapid, easy and reliable tracheal intubation in patients undergoing elective surgery. The purpose of this clinical trial was to evaluate the relative efficacy of the AWS laryngoscopes when used by experienced anesthetists in OSAS patients and to compare its performance with the Macintosh laryngoscope. The investigators hypothesized that, in comparison with the Macintosh, AWS would reduce intubation difficulty, as measured by the intubation difficulty scale (IDS) score.

Inclusion Criteria:

• ASA physical status 1-3 patients,
• aged 20years or older,
• undergoing uvulopalatopharyngoplasty(UPPP) surgery under general anesthesia for a polysomnography-confirmed diagnosis of OSAS.

Exclusion Criteria:

• unstable teeth or mouth opening of < 18mm
• Patients with any pathology of the neck,
• upper respiratory tract or upper alimentary tracts,
• risk of pulmonary aspiration of gastric contents,
• a history of relevant drug allergy.