Prediction of difficult intubation in apparently normal patients by combining modified mallampati test and thyromental distance: A prospective observational study

Introduction: Difficult intubation, often unexpected, remains a primary concern for the anesthesiologist. None of the bedside airway assessment tests have proven to be efficacious and highly predictive. This study was done to determine the sensitivity and specificity of Modified Mallampati test alone, Thyromental distance alone and in combination of both for predicting difficult intubation. Material and Methods: A prospective observational study was conducted in Universal College of Medical Sciences Teaching Hospital (UCMSTH), which involved 80 American Society of Anesthesiologist Physical Status (ASA PS) I patients undergoing elective surgeries under general anesthesia with endotracheal intubation. All patients were included for preoperative assessment by Modified Mallampati test alone and Thyromental distance measurement. The correlation between these tests and Cormack and Lehane laryngoscopic grading was done to find out the result. Results: Prediction of difficult intubation among 80 patients by Modified Mallampati test alone showed sensitivity of 72.7% and specificity of 98.6% whereas with Thyromental distance alone, showed sensitivity of 36.4% and specificity of 100%. When both predictors were combined, result showed sensitivity of 72.7% and specificity of 98.6% which was similar to that of Modified Mallampati test alone. Conclusion: This study concluded that sensitivity to predict difficult intubation was higher with Modified Mallampati test alone or in combination with Thyromental distance test whereas specificity was highest with Thyromental distance test alone.