Background and Goal of Study: The McGrath X-blade is an angulated blade attachment that is designed to be used with the McGrath MAC videolaryngoscope. We compared the McGrath X-blade with the C-MAC videolaryngoscope under the condition of a simulated difficult airway, through the use of manual in-line stabilisation. We present the findings of our interim study analysis.
Materials and Methods: Patients of ASA physical status I to III, aged 21 to 80 years old, undergoing general anaesthesia requiring tracheal intubation were recruited into this randomised controlled trial. Patients with history of or predicted difficult airway, gastro-oesophageal reflux disease, patients who decline to participate or lack the mental capacity to give consent are excluded from the study. General anaesthesia with muscle paralysis is performed in a standardised manner. Participants received intubation using either McGrath X-blade (MGX) or C-MAC (CM) videolaryngoscopy, with manual in-line stabilisation. Primary outcome measured was First Pass Success (FPS). Secondary outcomes included overall successful intubation within 2 attempts or 120 seconds, time to intubation, glottic view obtained and rates of complications. We aim to recruit 210 patients based on power calculation. 
Results and Discussion: An interim analysis of 91 participants was performed.  Patient demographics were comparable between both MGX and CM groups. First pass success at intubation was 76.9% in the MGX group vs 81.3% in the CM group (p=0.3). Overall success was 88.4% (MGX) vs 91.7% (CM) (p=0.73). The Cormack & Lehane laryngeal grade was superior in the MGX group compared to CM group (Grade I: MGX 55.8% vs CM 25%; Grade II: MGX 44.2% vs CM 47.9%; Grade III: MGX 0% vs CM 7.1%; p<0.001).  There was no significant difference in time to intubation [MGX 68.3s (mean 42.2s), CM 55.3 (mean 30.7s); p=0.087] and peri-operative complications between the two groups. 
Conclusion: Our interim analysis findings demonstrated superior glottic view using the McGrath X-blade, but with no significant improvement in intubation success or time to intubation compared to the C-MAC videolaryngoscope. We await the final results upon completion of the study.


03 / A comparative study of the efficacy of the McGrath X-blade vs the C-MAC Videolaryngoscope in patients with simulated difficult airways