Does Neck Circumference Help to Predict Difficult Airway in Obstetric Patients?

Failed intubation and ventilation in obstetrics remains one of the most common causes of death directly related to anesthesia. The reported incidence of failed intubation in obstetrics is 1:300, which is significantly higher than that in the non-obstetric population. A clinical screening test with high sensitivity and specificity for prediction of difficult airway may help reduce morbidity and mortality from general anesthesia. Few studies have identified increased neck circumference as the best single predictor of problematic intubation. However the cutoff point of this test for identifying patients at high risk of difficult intubation is not clear. The aim of this study is to determine the optimal cutoff point, which validates prediction of difficult ventilation and/or intubation for obstetric patients. Preoperative airway assessment will be done including neck circumference. Intraoperative difficult ventilation and/or intubation will be recorded. Optimal cutoff point of neck circumference will be calculated by Receiver Operating characteristics (ROC) curve.