This study evaluates the risk factors for difficult tracheal intubation in in obstructive sleep apnea hypopnea syndrome(OSAHS) patients undergoing uvulo-palato-pharyngoplast(UPPP)

OSAHS patients are high risk group of difficult tracheal intubation. In clinical application, unexpected difficult tracheal intubation is not rare. Difficult airway is a significant problem to these patients and the physicans in terms of mortality and morbidity.

This study collects risk factors as physical examinations（including modified Mallampati grade, neck circumference, lateral clinical craniofacial assessment and body mass index ,BMI）, Stopbang scores, polysommographic parameters (including apnea-hypopnea index, AHI and lowest SpO2, LSpO2), and special radiographic parameters in head and neck region. By using statistics method, predictive model to manage risks would be established.

Inclusion Criteria:

• diagnosed as OSAHS.
• receive UPPP under general anesthesia in Beijing Tsinghua Changgung Hospital
• ASA grade I or II

Exclusion Criteria:

• ASA grade III or above
• had received UPPP
• had fore-teeth loosed
• obstructive sleep apnea hypopnea were caused by hypothyroidism, acromegaly, or vocal cord paralysis.

Patients with moderate or severe obstructive sleep apnea hypopnea syndrome, which means apnea-hypopnea index( AHI) >15/h and lowest SpO2(LSpO2)<85% in polysommographic test.