Comparison of Macintosh blade vs Miller blade for glottic view and ease of intubation in adults.

Tracheal intubation is the gold standard for airway management because it secures a definitive airway, protects against gastric aspiration, and allows for high-pressure positive ventilation. The most common technique for tracheal intubation is direct laryngoscopy, which involves visualising glottis with a laryngoscope and inserting the endotracheal tube into the trachea.

Various direct laryngoscopes have been developed, but the Macintosh and Miller blades remain the most widely used. Macintosh blade is used to displace the epiglottis out of the line of sight by placement of the distal tip in the vallecula and tensing of the glossoepiglottic ligament. The Miller blade reveals the glottis by compressing the epiglottis against the base of the tongue.The Miller blade minimizes displacement of oral structures and reduces the risk of soft tissue trauma, whereas the Macintosh blade is easier to operate. The choice between these blades is influenced by factors such as the laryngoscopist’s preference and experience.

There exists a certain group of patients with flaccid epiglottis which cannot be predicted with routine bedside examinations. Elevation of such epiglottis with a  Macintosh laryngoscope does not provide a better view of the glottis.

This study is planned to compare the glottic view, effectiveness and ease of intubation with Macintosh blade and Miller blade during laryngoscopy. The study will be designed as a randomised controlled trial with 118 patients as subjects. 59 of these patients will be intubated using Macintosh Blade and 59 will be intubated with Miller’s Blade.

The glottic view will be graded by Cormack-Lehane grading and percentage of glottic opening score and the ease of intubation will be assessed with the help of intubation difficulty score. Additionally the haemodynamic response, duration needed for intubation and the satisfaction of the anaesthesiologist will be studied.