A Comparative Study of Glottic Visualization and Ease of Intubation with McCoy and Macintosh Laryngoscopes

Abstract

Introduction: The anaesthetist should protect the airways during induction, recovery and maintenance during anaesthesia. The Macintosh blade is the utmost prevalent blades with a slightly back curved that extends all the way to the tip. The McCoy blade is grounded on a normal Macintosh blade with a hinged tip and is functioned by a lever mechanism located at the handle back. Objective: This study attempts to compare McCoy and Macintosh blades to facilitate intubation for glottis imaging. Place and Duration: In the Department of Anesthesia, Divisional Headquarter teaching Hospital Mirpur Azad Kashmir for six months duration from June 2021 to November 2021. Method: The study included 70 Grade I and II ASA adults of both sexes (20 to 60 years) who endured planned surgery under GA necessitating intubation by endotracheal tube. Using a computer-generated randomization table, individuals were assigned randomly to any of the 2 groups contingent on the type of laryngoscope blades used while doing intubation. After anaesthesia induction, ‘laryngoscopy’ was done and the intubation of trachea was done. McCoy Laryngoscope Blade was used in In Group A while Macintosh Laryngoscope Blade in Group B. The number of trials, Cormack Lehane classification, the necessity for external laryngeal manipulation and degree of intubation difficulty were evaluated. Results: Both groups were comparable for sex, weight, age, height, MPC grading, ASA status and among the two groups; no statistically significant alteration was noted (p-value> 0.05). In Group A and B Cormack Lehane classification in Grade-I scored 82.9% and 60%, correspondingly, while Grade-II scoring in Group A and B were 17% and 25.8%, correspondingly. The Grade-I Intubation Difficulty score (IDS) in Groups A and Group B were 88.6% and 80%, respectively, while Grade-II IDS in Groups A and B were 11.4% and 14.2%. 8.5% of patients in group A and 5.7% of patients in group B required two intubation attempts. Conclusion: There are no significant fluctuations to the glottis visualization with Macintosh and McCoy laryngoscopes, but in terms of external manipulation of larynx, the McCoy laryngoscope is superior to the Macintosh laryngoscope in terms of comfort of intubation. Keyword: endotracheal tube, Macintosh blades, Macintosh and McCoy laryngoscopes.