Straight blades improve visualization of the larynx while curved blades increase ease of intubation: a comparison of the Macintosh, Miller, McCoy, Belscope and Lee-Fiberview blades

A randomised controlled trial comparing the McGrath® videolaryngoscope with the straight blade laryngoscope when used in adult patients with potential difficult airways*

“…As suggested by Arino's study [6], a good laryngeal view with an intubating device did not always result in improvement in the ease and conditions for tracheal intubation. Despite achieving more grade-1 glottic views in patients with a Mallampati score ‡ 3, the median time taken for successful intubation with the McGrath videolaryngoscope was similar to that using the Henderson straight blade.…”

“…As a result, anaesthetists agree that a plan for difficult airway management improves outcomes [4,5]. Both the American Society of Anesthesiologists' (ASA) [6] and the Difficult Airway Society's (DAS) [7] guidelines suggest that initial techniques to overcome a poor laryngoscopic view or a difficult tracheal intubation include the use of an introducer or gum-elastic bougie and ⁄ or an alternative laryngoscope blade. The choice of alternative blade usually depends upon clinical constraints and the experience of the individual anaesthetist.…”

Lower flange modification improves performance of the Macintosh, but not the Miller laryngoscope blade

“…6 So far, no single approach has proven to be superior with respect to the prevention of tooth damage. Although larger controlled trials, comparing different laryngoscopes with regard to laryngeal visibility 19 or frequency of bladetooth contact 11 have been conducted, trials with dental injury damage as a primary outcome parameter would be ethically challenging, and are still lacking. Finally, the majority of patients in this study did not feature any airway abnormalities, and our results may not be applicable to patients with difficult airways.…”

Does the type of laryngoscope blade matter when grading the glottic view?

“…With the emergence of ultrasound as an accurate diagnostic tool that can yield information in real time, imaging of the airway structures is a possibility and represents a potentially useful method for predicting difficult intubation. Several papers (including ours [2]) demonstrate the utility of ultrasound in examining the airway and assessing for difficult laryngoscopy [3,4]. Going forward, we expect ultrasound to increase in popularity as a valuable tool to predict the difficulty of intubation.…”