STUDY OBJECTIVE: To determine if a high score (≥ 3) on the STOP-Bang screening 
questionnaire for obstructive sleep apnea (OSA) predicts whether obese patients 
are at high risk for OSA and increased risk of difficult airway.
DESIGN: Prospective, questionnaire-based clinical assessment.
SETTING: University-affiliated hospital.
PATIENTS: 127 ASA physical status 2 and 3 patients, who were scheduled for 
elective bariatric surgery.
INTERVENTIONS: Patients were allocated to three groups. Group 1 patients had a 
previous history of OSA, Group 2 patients had no history of OSA but did have a 
high STOP-Bang score (≥ 3), and Group 3 patients had no history of OSA but did 
have a low STOP-Bang score (< 3). Groups 2 and 3 only were assessed using the 
STOP-Bang questionnaire. After induction and intubation of the patient, an 
anesthesiologist who was blinded to the three study group allocations completed 
an airway questionnaire on the three study groups.
MEASUREMENTS: The frequency of difficult airway, difficult mask ventilation with 
or without muscle relaxation, poor visualization of the vocal cords, difficulty 
in blade insertion, and difficult intubation were compared.
MAIN RESULTS: The group of patients with high STOP-Bang scores (Group 2) and 
those patients previously diagnosed with OSA (Group1) showed a higher risk for 
difficult airway than the patients with low STOP-Bang scores (Group 3; P < 
0.001).
CONCLUSION: The STOP-Bang score may be used as an effective predictor of 
difficult airway in obese patients. Obese surgical patients with 
unknown/undiagnosed OSA status should be evaluated using the STOP-Bang 
questionnaire score.