Accuracy of STOP-Bang Questionnaire in Predicting Difficult Mask Ventilation: An Observational Study

Abstract

Introduction Difficulty with bag-mask ventilation after the induction of general anesthesia and muscle relaxation places the patient at risk for a prolonged period of apnea and hypoxia and thus, at an increased risk of morbidity and mortality. This study was designed to assess the accuracy of the STOP-Bang questionnaire in predicting difficult mask ventilation (DMV) in patients receiving general anesthesia for elective surgical procedures. Methods It was a prospective cross-sectional, observational study conducted at a university teaching hospital. A total of 530 patients undergoing surgery under general anesthesia with endotracheal intubation were enrolled. STOP-Bang questionnaire was filled at pre-operative anesthesia assessment. Ease or difficulty of mask ventilation was assessed and documented by a senior resident responsible for intraoperative anesthetic management. Results Out of 530 patients, 139 (26.22%) had a STOP-Bang score of ≥ 3, of whom 55 (39.5%) were found to have DMV. Out of 391 patients with a STOP-Bang score of < 3, only 29 patients (7.5%) had DMV (P ≤0.001). Snoring, high blood pressure, BMI more than 35 kg/m(2), age more than 50 years, neck circumference more than 40 cm, and male gender were significantly associated with DMV. The accuracy of the STOP-Bang questionnaire in predicting difficult mask ventilation was 78.68% (95% CI 74.99-81.95) with a negative predictive value of 92.58%. The sensitivity and specificity were found to be 65.48% and 81.17% respectively. Conclusion STOP-Bang score has a high negative predictive value and can be very useful in ruling out the possibility of difficult mask ventilation.