Airway risk assessment is an essential part of the preoperative anaesthetic protocol. Numerous investigations have been conducted in an effort to predict the occurrence of difficult airway through physical examination & modified Mallampati test is the most popular one. But Research has shown that it only had moderate ability to predict difficult airway.

Voice signal is a more recent novel and comprehensive indicator that can reflect both   anatomical structure and function of the airway. So, voice analysis may offer a way to predict difficulty in airway manipulation.

This study aimed to determine whether acoustic features are valuable as method to predict difficult laryngoscopy (DL) when it is used alone and in conjunction with modified Mallampati test in patients scheduled to undergo elective surgery under general anaesthesia.

This study will include 250 adult patients who will be undergoing elective surgery under general anaesthesia with tracheal intubation. Preoperatively, clinical airway evaluation will be performed and modified Mallampati grading will be done.The Class I &II is associated with easy laryngoscopy & Class III or IV is usually associated with difficult laryngoscopy.

Five phonemes considered as the vowels a, e, i, o,u  will be recorded and their first four formants (describe as f1, f2, f3, f4 ) will be analysed. Laryngoscopy will be done after induction of anaesthesia & adequate muscle relaxation. Difficult Laryngoscopy will be called when the anaesthetist, using direct laryngoscopy, classified the patient as 3 or 4 in accordance with the Cormack and Lehane classification system.

It is expected that voice parameters in conjunction with modified Mallampati test will have higher predictive value to predict difficult laryngoscopy & intubation than modified mallampati test alone during general anaesthesia.