A Comparative Crossover Randomized Study of Miller and Macintosh Blade for Laryngoscopic View and Ease of Intubating Conditions in Adults

Background: Although several types of laryngoscope blades of different sizes and shapes are present, Miller (MIL) blade is the most preferable blade among paediatric population. However, there is dearth in the literature regarding the use of these blades in the adult population. This study aimed to compare the laryngoscopic view and ease of intubation using MIL and Macintosh (MAC) blade among adults. Methods: A total of 172 patients who were >18 years age, with ASA grades I and II, undergoing elective surgeries with general anaesthesia were included. Patients were distributed in two groups (MAC/MIL and MIL/MAC), where laryngoscopy was first done with MAC blade, followed by MIL blade in the MAC/MIL group and vice-versa in the MIL/MAC group. Grading of laryngoscopic views, number of attempts, ease of intubation and use of backward, upward, rightward pressure (BURP) were noted. R v 3.6.0 was used for statistical analysis and P values≤0.05 were considered as statistically significant. Results: MIL blade showed better laryngoscopic view compared to MAC blade (32.6% vs. 15.1%; P< 0.002). BURP application helped improve the laryngoscopic views with MAC blade. Intubation with MIL blade was easier with regards to ease of intubation and number of attempts 19 (P value<0.05). Conclusion: Glottis visualization is better with the MIL blade as compared to the MAC blade. Therefore, the MIL blade might be helpful in securing the airway among adult patients.