Glidescopes, one of the several videolaryngoscopes in use, are very easy to use. However, intubation with the Glidescope is very different than direct laryngoscopy. I have seen many novice Glidescope users struggle to intubate, despite having great views of the larynx. Failure to recognize the differences of using the Glidescope can make intubation not only frustrating but also hazardous to your patient. Beginners almost always make the same few easy to correct mistakes. Let’s explore those mistakes and discuss how to correct them.
The GlideScope Video Laryngoscope, (Verathon Medical), has a color camera embedded in a curved, high impact laryngoscope blade that resembles a MacIntosh (Mac) blade with a greater curvature. The distal third of the blade angles upward at about 60 degrees. The image appears on a small, color, stand-alone video monitor.
Any intubation can cause oropharyngeal or dental trauma. Although improved visualization of the larynx in many ways eliminates much of the risk, the Glidescope is not immune. The more unique injuries with video-laryngoscopy are typically associated with focusing on the beautiful image of the larynx on the monitor, rather than looking at the patient.
There have been case reports of perforating the right palatopharyngeal wall during intubation with the GlidesScope(1,2). The most likely cause was blind insertion of a styletted ETT into a taut tonsillar pillar while looking at the monitor for the ETT to appear.
You can also injure teeth and lips by not watching the patient during placement. So how do we use the Glidescope safely?
Tricks To Using The Glidescope Easily and Safely
Insert Midline Under Direct Vision
The Glidescope blade is shaped like a longer, more curved Macintosh blade, however, insertion technique is quite different. The MAC blade is inserted to the right side of the mouth and used to slide the tongue to the left. Unlike the MAC, the GlideScope blade must be inserted into the center of the mouth and rotated around the tongue in order to line up the camera lens with the larynx.
Always insert the GlideScope midline into the mouth looking at the patient until its tip has passed the palate. You can glance up at your monitor as you’re doing this but this is like glancing in your side view mirror of your car as you are preparing to change lanes — you don’t want to take your eyes off the “road” or you’ll crash.
Once the blade has turned the corner into the pharynx, look at the monitor while glancing at your patient to optimally position the blade.
Stylet Curve Must Match Curve of The Glidescope Blade
Once the blade is positioned with the larynx in view, insert the ETT along the right side of the blade. Even though you may have a magnificent view of the larynx on the monitor at this point, the larynx isn’t in the direct line of sight, as it would be with the MAC. Therefore you must use a properly curved stylet to guide the endotracheal tube into the larynx. Unlike the typical “hockey-stick” shape used during direct laryngscopy, the stylet should match the curve on the GlideScope blade. If I am using a standard stylet, I place the stylet into the ETT and then mold it against the GlideScope blade so that the curves match. You can leave the ETT in the sleeve to keep it clean.
Because a standard disposable stylet is so malleable, occasionally it will straighten during insertion, especially if the space it tight. This leads to the frustrating situation of being able to see the larynx and not being able to “get there”. A stiffer Glidescope specific, non-disposible stylet is available that is preconfigured to the correct curve. It has a blunt tip to minimize potential for trauma, however it is very stiff and can potentially damage pharyngeal structures if you are not gentle. Do pull it back slightly before fully inserting the ETT into the trachea.
Rotation Of The ETT Is Key
Regardless of which stylet you’re using, insert the endotracheal tube with the curve aimed toward the right side of the mouth, 3:00 o’clock position, under direct vision until you start to see it on the monitor.
At this point rotate the tube back toward the midline (12 o’clock position) and aim it at the glottic opening.
If the mouth is small, it can be helpful to insert the ETT into the mouth first, slide it far to the right side of the mouth, and then insert the GlidesScope blade midline.
Look At The Patient Until Tip Of ETT Appears On Monitor
This sounds obvious, but watch what you’re doing. There is a strong temptation to just look at your monitor while you’re inserting the blade and the ETT.
Look at the patient during insertion of the ETT as described above until its tip has passed out of view beyond the tonsillar pillars. Only after the tip of the ETT has turned the corner into the pharynx should you look at the monitor, otherwise you can injure teeth, lips, tongue and pharyngeal structures. Manipulate the tip of the tube through the glottis, then pause to withdraw the stylet 2-3 cm to effectively soften the tip of the ETT. Advance the ETT into the trachea looking at the monitor. Remove the GlideScope looking at the patient, not the monitor.
Switching your focus of attention is comparable to what you do when changing lanes while driving. When changing lanes you are watching the road ahead (to avoid a collision) but you are also glancing into your side and rear-view mirrors so you don’t hit anyone around you.
Link to Vimeo video clip From Anyone Can Intubate, showing Glidescope intubation, as well as other advanced techniques as well as a few other difficult intubation techniques..
There are several common errors that most people make when first mastering the Glidescope. This is the advice I give my students.
A More Neutral Head Position Is Helpful
Decreasing the angle the ETT must travel can help. Unlike with the MAC, this typically means placing the head and neck in a more neutral position rather than an extreme sniffing position.
Don’t Pick Up The EPIGLOTTIS
The most common error, in my experience, is to insert the Glidescope blade too deeply. While it’s optimal to place a standard MAC blade tip into the vallecula during direct laryngoscopy, it is flexible enough that one can often use it like a straight blade to pick up the epiglottis. You can’t do this with the Glidescope.
One of the most common errors is inserting the GlideScope as deeply as you possibly can, lifting the epiglottis and placing the very tip of the Glidescope blade on the anterior commissure of the vocal cords. If you do this you will have a superb view of the larynx —but the glottis will be very high in your field of view and you won’t have either the optimal angle or the maneuvering room to manipulate the tip of the ETT into the larynx.
Instead, pull the blade back a bit and insert its tip behind the epiglottis into the vallecula. This gives you room to maneuver the ETT.
Don’t Insert The ETT Tip Too Posteriorly
Another common error is inserting the endotracheal tube tip too posteriorly into the back of the pharynx, allowing it to drop as far as possible toward the back of the throat. From this position, as you can see in this simulated intubation, the tip of the ETT tends to hit the back of the arytenoids and it may be frustratingly difficult to insert through the highly visible glottis.
Instead, in order to place the glottis within the arc of the styletted ETT, pull the ETT back until you can just see its tip in the upper right hand corner of your monitor. Rotating the tip forward from that position typically allows the tip to enter the glottis.
Don’t Forget To Lift The Jaw
Providers have such a great view of the larynx, they forget that they still have to create a clear path for the ETT to successfully enter the larynx.
Don’t forget to lift the jaw upward. Even if you are avoiding neck motion for cervical spine precautions, you can still lift the jaw.
Ask For Cricoid Pressure
Again, because we usually ask for cricoid pressure when we can’t see the larynx, we forget that cricoid pressure can help change intubation angles when we can see it. Don’t forget to ask for cricoid pressure in order to bring the larynx downward into the arc of the ETT curve.
The Glidescope is a wonderful tool. However, the ease of getting a wonderful view of the larynx can fool you into concentrating on that image, and ignoring the patient and forgetting that you still need to get alignment between larynx and endotracheal tube by manipulating the angles in insertion. Practice will make perfect.
May The Force Be With You
Christine Whitten MD
- Palatopharyngeal wall perforation during Glidescope intubation. Leong WL, Lim Y, Sia AT. Anaesth Intensive Care. 2008 Nov; 36(6):870-4.
- Complications associated with the use of the GlideScope videolaryngoscope. Cooper RM. Can J Anaesth. 2007 Jan; 54(1):54-7.