Follow the twitter links for the insanity
It all started very innocently with this question (again) on twitter.
My gut feeling is that it doesn’t work so I rigged up my son to try it out. In my opinion it does not give you head elevation that will allow you to visualize the glottis optimally. With the neck in extension (AO extension) and torso tilted up, the head can still need to be elevated (base of neck flexion moves the head forward on the thorax). Some head elevation may occur because the tilted body shifts down in the bed but it still may not be optimal and you may have a hard time to manipulate the head up and keep it elevated off the end of the stretcher.
If you are ever scoping yourself or someone else, see what a difference doing head forward positioning does to the laryngoscopic view from within the airway (not moving any tissue with a blade to straighten the curves). IMHO it makes your view much better … from grade 2b/3/4 to <=2a. My next nasoendoscopy selfie will have to compare views within the airway of sniffing (Ear to sternal notch) versus extension. See the following video for the AIME demonstration of the effect of head elevation. (PS note that in all of this JAW THRUST is also a crucial piece to straightening the curves and “aligning the axes”).
At the very least, it appears that the tracheal axis is less favorable for tube delivery in the extension position: more tracheal inclination and thus exaggerated corrugation effect from the tracheal rings on tube (tip) delivery.
Follow some of the twitter links for the insanity if you dare. When I have time I will translate it into more readable format for those not inclined to twitter.