Written by Aaron Lacy
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When comparing four different single-use videolaryngoscopes (VLs), the McGrath Mac had better direct and indirect glottic visualization, led to fewer intubation attempts, and reduced the need to resort to a hyperangulated blade during endotracheal intubation.
Why does this matter?
Video laryngoscopy (VL) continues to make its case as the standard of care, and there are many types of VLs to choose from. If one VL provides a better view, leading to decreased intubation attempts, this could be clinically significant.
One VL to rule them all…
589 adult patients who needed standard endotracheal intubation for operative cases at a teaching hospital were intubated using one of four single-use VLs. Randomization was pragmatic, and devices were switched through four scheduled time blocks between four different anesthesia departments, with one device being used per block. Every intubation underwent the same sequence of events:
Step 1: Direct laryngoscopy with selected VL, with operator reporting visualized Cormack-Lehane (CL) score
Step 2: Rating of the glottic visualization from indirect laryngoscopy (i.e. screen view). If CL grade was I/II an intubation attempt took place. If CL scoring was III/IV the operator proceeded to the third step. If the initial intubation attempt failed the operator also proceeded to the third step.
Step 3: The attending anesthesiologist would switch the VL to each VL company’s specific hyperangulated blade, rate the glottic view via the screen, and attempt intubation.
Primary outcome was the need to move to Step 3 (failure to intubate on first pass or failure to obtain grade I/II view). Between the four VLs, the McGrath-Mac had the lowest rate of progression to Step 3 (22/180, 12%) compared to the C-MAC-S (39/132, 30%), C-MAC-S-PM (29/139, 21%), and APA (35/138, 25%). Overall, intubation attempt number was less and glottic visualization was better in the McGrath-Mac compared to the other VLs. A large portion (125/589, 21.2%) of enrolled patients ended up progressing to step 3. The McGrath-Mac did statistically better than others (using a 99.2% confidence interval since there were multiple comparisons). Like many things in medicine, it appears that frequency of VL use is also an important step to proficiency. Know what tool you have available and familiarize yourself with it to maximize proficiency.
Source
Macintosh Videolaryngoscope for Intubation in the Operating Room: A Comparative Quality Improvement Project. Anesth Analg. 2021 Feb 1;132(2):524-535. doi: 10.1213/ANE.0000000000005031.
