Comparison of Direct and Video Laryngoscopy Using the Same C-MAC® Macintosh Blade for Glottic Visualisation and Intubation Characteristics in Adults Undergoing Elective Surgery: A Prospective Randomised Interventional Study

Background and Aims: Video laryngoscopy (VL) has transformed airway management. However, whether this improved view consistently translates into better intubation performance remains uncertain. The C-MAC ® video laryngoscope uniquely allows both direct laryngoscopy (DL) and VL using the same Macintosh blade. The primary objective was to compare glottic visualisation between DL and VL using the same C-MAC ® Macintosh blade. The secondary objectives included the comparison of intubation characteristics, haemodynamic responses and complications. Methods: A total of 110 patients were recruited, and all 110 were included in the final analysis. All patients underwent glottic visualisation using both DL and VL with the C-MAC ® . Patients were randomised regarding the sequence of laryngoscopy, and the allocated technique was used for tracheal intubation. Glottic visualisation was assessed using the Modified Cormack–Lehane (MCL) grading system and percentage of glottic opening (POGO) score. Secondary outcomes included intubation time, first-attempt success rate, ease of intubation as assessed by the Intubation Difficulty Scale, haemodynamic response and complications. Results: VL resulted in a higher proportion of MCL Grade 1 views (72.73% vs. 54.55%; P = 0.006) and a greater frequency of complete glottic visualisation (POGO score 100: 40.0% vs. 24.55%; P = 0.004). Intubation time, total insertion time and first-attempt success rates were comparable between groups. Conclusions: VL significantly improves glottic visualisation compared with DL in normal airways. The clinical advantage of VL may be more pronounced in anticipated difficult airway situations. The study highlights that improved glottic visualisation alone may not necessarily improve intubation efficiency when blade design and operator factors are standardised.