European Journal of Cardiovascular Medicine

Background:  Airway assessment is a vital part of pre-anesthetic evaluation. Amongst numerous existing methods for airway assessment, Modified Mallampati Score (MMS) is the most commonly used. The pitfall lies in the patient to actively perform a mandatory action, which is difficult in unconscious and moribund patients. Ultrasonography of upper airway requires less patient cooperation and might add to the value of traditional airway assessment. Aim: To evaluate whether the ultrasonographic measurement of maximal tongue thickness (MTT) and hyoid bone visualization predicted difficult laryngoscopy and intubation and to evaluate the correlation of MTT with other clinical parameters. Materials and Methods: This prospective observational study was conducted in 100 patients aged 18 to 70 years of ASA physical status 1 to 3. Ultrasonographic measurement of MTT and visualization of hyoid bone was done with patient lying supine in ‘sniffing position’ preoperatively. MTT was measured using a curvilinear probe in the median sagittal plane. Hyoid bone was visualized using a linear probe placed in the mid sagittal plane. After induction of anaesthesia and muscle relaxation, difficulty for laryngoscopy and intubation was assessed. Results: In our study, independent predictors for difficult laryngoscopy and for difficult intubation were MTT of ≥5.97cm and ≥6.54cm, respectively. Significant correlation between MMS and MTT was noted. Visualization of hyoid bone had no predictive value for difficult laryngoscopy and intubation. Conclusions: Our study concluded that MTT is an independent predictor of difficult laryngoscopy and intubation.There was a positive correlation between MTT and MMS.