Comparison between Macintosh, Miller and McCoy laryngoscope blade size 2 in paediatric patients - A randomised controlled trial

Background and Aims: Paediatric airway needs special consideration as it is not a miniature replica of adult airway, rather it has different anatomy with different proportion and angulations. This study was conducted with the aim to find a laryngoscope blade that provides best laryngoscopic and intubation conditions in paediatric patients of age 2-6 years. Methods: This trial was conducted in a total of 75 children age 2-6 years, either gender, with American Society of Anesthesiologists grade I or II scheduled for elective surgery under general anaesthesia. They were randomly allocated to groups A, B and C to be intubated with Macintosh, Miller and McCoy blades, respectively. Intubation Difficulty Score (IDS) was considered as primary outcome, and Cormack-Lehane grade and Percentage of Glottic Opening (POGO) score were taken as secondary outcome. Data were compared by ANOVA or Kruskal-Wallis or chi square test using Statistica, SPSS and GraphPad Prism softwares. P < 0.05 was considered statistically significant. Results: IDS score was significantly lower (P = 0.002) in group B (0.6 +/- 0.7) as compared to group A (1.4 +/- 0.9) and group C (1.3 +/- 1.1); majority of patients in group B (48%) had Cormack-Lehane grade. (P = 0.002) unlike group A (0%) and group C (20%) and POGO score (P < 0.001) was higher in group B (86 +/- 23.4) when compared with groups A (68.2 +/- 20.5) and C (59.8 +/- 28.9). Haemodynamic changes and other intubation parameters were comparable among the groups. Conclusion: Miller blade may be considered superior to Macintosh and McCoy blades in terms of glottic visualisation and ease of intubation in paediatric patients.