What happens when you use a Mac blade as a Miller? Is this legal or will the airway police raid your airway box and relinquish your intubation privileges? If you choose to use the Mac as a Miller, how do you do it right and how do you do it wrong?
The Macintosh and Miller laryngoscopes have been designed specifically to take on different obstacles in airway management and are utilized in different ways. When using the Mac blade, the broad tip of the blade was designed to be seated directly into the vallecula, engaging the hyo-epiglottic ligament, and when lifted, displacing the soft tissue anteriorly to provide a view. Alternatively, the Miller blade is a straight laryngoscope, designed to be placed below the epiglottis and expose the glottis by lifting the epiglottis out of the way. Its length and narrow tip are designed specifically for this purpose. While the Miller blade historically designed to tackle the ‘floppy’ epiglottis of pediatric airways, its use spread through all airway sizes and ages.
But can you use a Mac blade as a Miller? The answer is yes but with some caveats. The ideal situation is when your view is obscured by the epiglottis, whether it be an aberrantly large epiglottis, epiglottitis or even angioedema. Let’s check out examples of using the Mac as a Miller and doing it right and doing it wrong.
Video 1: In this first video, during the initial attempt, the view was obscured by epiglottis. In the second attempt, the blade tip is dipped under the epiglottis to lift it, providing a fantastic view. We also see difficulty with tube passage until the tube is rotated to help with anterior hang up.
However, notably, there are many ways to make your view worse or make tube passage more challenging.
Video 2: Here we see that the view is exceptionally close to the glottis. This makes it difficult to assess where your tube will come into view and can make intubation more challenging. In this video, it is not clear whether or not using the Mac as a Miller was intentional.
Video 3: Here we have a pretty extreme example of being far too close to the glottis. The blade tip looks like it’s literally about to go down the trachea. Importantly, we see that as a result, the tube has a difficult time passing because the blade is obstructing the airway. Safe to say this is how to do a Mac as a Miller approach wrong.
When the Mac is accidentally used as a Miller is frequently from riding the soft palate to the posterior pharynx and subsequently landing too deep. Upon withdrawal, the epiglottis is caught by the tip of the blade.
Video 4: In this last example, we see a pretty solid combo of combining a Mac as a Miller approach with a bougie for successful intubation. Could the argument be made that better positioning of the blade in the vallecula would have promoted a better view? Yeah probably. Has the point been made that a Mac can be used as a Miller successfully? You’ll have to decide.
The Debrief
- The Mac can be successfully used as a Miller. The ideal context would be when the epiglottis is obscuring the view of the cords.
- The Mac can be inadvertently used as a Miller leading to a view that’s too proximal to the cords or a blade that obstructs tube passage.
- Don’t forget to bougie.
- Check out this CriticalCareNow post about choosing laryngoscope blades
