ENHANCING DIFFICULT AIRWAY PREDICTION IN OBESE PATIENTS: INTEGRATING STOP-BANG WITH ADDITIONAL AIRWAY ASSESSMENT TOOLS

Abstract

Objective: To determine the diagnostic accuracy of the STOP-BANG questionnaire for predicting difficult mask ventilation (DMV) in obese adults undergoing elective surgery, and to evaluate whether combining STOP-BANG with conventional bedside airway assessment variables improves predictive performance beyond STOP-BANG alone. Study Design: Cross-sectional diagnostic accuracy study. Place and Duration of Study: Place and Duration of Study: Department of Anaesthesiology, Sindh Institute of Urology & Transplantation (SIUT), Karachi, Pakistan, from March 2026 to June 2026. Methodology: Adults aged 18–60 years with body mass index (BMI) ≥ 30 kg/m² and American Society of Anesthesiologists (ASA) physical status II–III scheduled for elective surgery under general anaesthesia with endotracheal intubation were consecutively recruited. Preoperative assessment included STOP-BANG scoring (using Asian-specific thresholds), modified Mallampati score (MMS), thyromental distance (TMD), mouth opening, upper lip bite test (ULBT), BMI, and neck circumference. The attending airway provider remained blinded to the STOP-BANG score. Directly observed intraoperative airway outcomes served as the reference standard. Diagnostic accuracy of STOP-BANG ≥ 3 was evaluated via sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall accuracy, receiver operating characteristic (ROC) analysis, and a disjunctive combined screening model (STOP-BANG ≥ 3 OR MMS III/IV). Results: Among 233 obese surgical patients, STOP-BANG ≥ 3 was present in 74 (31.8%). DMV occurred in 50 (21.5%) and difficult tracheal intubation (DTI) in 38 (16.3%); 26 patients (52.0%) with DMV also experienced DTI. For DMV, STOP-BANG ≥ 3 yielded sensitivity 72.00%, specificity 79.23%, PPV 48.65%, NPV 91.19%, and overall diagnostic accuracy 77.68%, with an area under the ROC curve (AUC) of 0.81. Combining STOP-BANG ≥ 3 with MMS III/IV increased sensitivity to 88.00% and NPV to 95.62%. Conclusion: STOP-BANG ≥ 3 demonstrated good diagnostic discrimination for DMV in obese surgical patients, functioning effectively as a rule-out screening tool due to its high NPV. Combining STOP-BANG with bedside physical assessments significantly enhanced predictive sensitivity, supporting a multimodal risk-stratification approach prior to induction.