ABSTRACT
Introduction: Preoperative diagnostic validity of airwayassessment help for prediction of difficult airway. Severalmodels were established for prediction of difficult intubation.In this study, we aim to predict difficult intubation in nonobese patients from various airway predictive indices suchas modified mallampati grade, neck movement (NM), neckcircumference (NC), thyrometal distance (TM), NC/TMD.Material and Methods: Total 121 patients with 18-72 yearsof age, ASA grade I or II, scheduled for elective surgerythat required general anaesthesia. Difficulty of intubationwas assessed using the IDS for each non-obese patient. Thestudy population was divided into two groups Easy (IDS <5)and Difficult intubation (IDS ≥5). Preoperative assessmentsincluded Mouth Opening (MO), modified mallampati grade,neck movement (NM), neck circumference (NC), thyrometaldistance (TM), NC/TMD. Multivariate analysis was usedto predict independent risk factors. Receiver OperatingCharacteristic Curve analysis (ROC analysis) was performedfor the airway assessment tests. The area under curve (AUC)was calculated.Results: The weight (59.74±7.76 kg and 65.00±5.92 kg)and BMI (21.51±1.79 and 23.8157±1.09) were significantlydifferent in between easy and difficult intubation. TheMouth Opening, NC, TMD, and NC/TMD were significantlyindependent risk factor for difficult intubation. NC/TMDwas showed higher sensitivity, specificity, positive predictivevalue (PPV) and a negative predictive value (NPV) with thirdlarge area under the curve (AUC) on the ROC curve.Conclusions: This study shows that the NC/TMD ratio canbe considered as a better predictor of difficult intubation innon-obese patients.