A randomized controlled trial to compare the hemodynamic response to orotracheal intubation with c-mac video laryngoscope versus c-mac video stylet in adults receiving general anesthesia for elective surgery

Laryngoscopy and intubation stimulate the sympathetic nervous system causing an increase in heart rate, blood pressure, pulmonary capillary wedge pressure and intracranial pressure. This hemodynamic response is transient, and is well tolerated by healthy individuals but can have deleterious consequences in high-risk patients such as those with hypertension, coronary artery diseases, intracranial space occupying lesion etc. Video laryngoscopy is now becoming a preferred method of tracheal intubation with its improved visualization and widespread availability. However, previous literature has shown that hemodynamic response to video laryngoscopy is similar to that of direct laryngoscopy as both the devices involve introduction of blades into the laryngopharynx exerting pressure to the base of the tongue, lodgment in the vallecula and elevation of the epiglottis**.**

C-MAC Video stylet with a deflectable tip has been recently introduced to facilitate orotracheal intubation in adults. It is an optical stylet that allows indirect view of laryngopharyngeal structures without exerting pressure on the adjoining tissues. However, introduction of the stylet into the oral cavity requires application of jaw thrust or manual lifting of the mandible by hooking the lower jaw to create a pharyngeal space in order to facilitate visualization of glottis. These maneuvers are also known to elicit a sympathetic response, however, there is no research comparing the hemodynamic response of video laryngoscopy versus video stylet intubation which involves manual displacement of the jaw.

There is paucity of literature comparing the hemodynamic responseto orotracheal intubation by C-MAC video laryngoscope versus C-MAC video stylet in adult patients receiving general anaesthesia for elective surgery.

Our study will help us identify if  there is any difference in the hemodynamic response to orotracheal intubation using C-MAC video laryngoscope compared to C-MAC video stylet in adult patients receiving general anaesthesia for elective surgery and thus select appropriate laryngoscope for intubation in high risk patients.