Comparing the effects of endotracheal intubation with video laryngoscope on vocal functions using video-assisted fibreoptic intubation (VAFI), bougie and stylet in adults undergoing general anaesthesia for elective surgeries; three-arm randomized controlled trial

During general anaesthesia for surgical procedures, patient’s breathingwill be maintained by fixing an endotracheal tube inside the airway, whichwill be visualized using a laryngoscope. Video laryngoscope is one suchinstrument used for intubating a difficult airway. Various adjuncts can beused as a guide to locate the trachea like bougies and stylets. However,these adjuncts have the disadvantage of limited mobility and flexibility which can result in injury to the larynx. This causes postoperative sore throat, hoarseness of voice and weakness of voice. Video-assisted Fibreoptic Intubation (VAFI) is a newer technique withcombined use of fibreoptic scope and video laryngoscope. Not muchresearch is available on comparison these methods on voice complications in Indian population.This study compares the efficacy of VAFI compared to bougie guidedendotracheal intubation using video laryngoscopy. 

All patients undergoing general anaesthesia will be screened using inclusion criteria like age>18 years, ASA PS 1-II, and normal BMI. Olderpatients, emergency surgeries, critically ill and pregnant patients will beexcluded from the study. Participants will be blinded and divided into 3 groups. After written informed consent, a voice sample will be collected for voice analysis. S/Z ratio and maximum phonation time will be measured. Standard institutional protocol forgeneral anaesthesia will be followed. Intubation will be done using videolaryngoscopy with VAFI, bougie or stylet as adjunct depending on the assignedgroup. Efficacy of the adjuncts will be compared using time taken tointubate, success at first attempt, and number of attempts at intubation. 24hours postoperatively, voice sample will be collected for voice analysis.Patient will be asked to fill out the Voice-Handicap Index (VHI) questionnaire.S/Z ratio and maximum phonation time measurement will be repeated 24 hourspostoperatively.

Data will be collected during the study period of 12 months. Following this,data analysis will be done to identify the superior method in terms of less voice complications, shorter intubation time, higher first attempt success rates,  and lesser number ofattempts. This study would help in choosing a better guide for intubationwhich could be extrapolated for avoiding vocal cord injury. Limitations of thisstudy include performer bias and need for assistant during the procedure.