Hyperangulated Hiccups

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Jonathan Hootman, MD
Jonathan Hootman, MD

EM resident and aspiring intensivist, with a love for airway, ultrasound, and artisanal balanced crystalloid. You can find him cooking, pug wrangling, hiking, or napping with his wife in his spare time.

Brock Hashim, MD
Brock Hashim, MD

EM resident with a passion for teaching, airway, wellness, and professionalism. Sci-fi aficionado, hiking enthusiast, chef extraordinaire and loving husband outside of the department.

The Pre-brief

Maybe you’re tired of reaping the benefits of bougie-first intubation and looking to try a different gadget in your intubating toolbox, or maybe you’re just looking to improve your already deft hand at hyperangulated intubations. Whatever the reason, we’ll discuss some of the important hiccups encountered with use of a hyperangulated blade and tips and tricks on overcoming them. 

The GlideScope® (Verathon Medical, Bothell, WA) and the C-MAC (Karl Storz, Tuttlingen, Germany) are two of the most commonly used video laryngoscopes. Both companies produce a hyperangulated blade (GlideScope® LoPro, C-MAC D blade) in addition to standard geometry blades. The following tips on hyperangulated video laryngoscopy (VL) are written with use of a GlideScope® hyperangulated blade (e.g. LoPro S3 or S4) in mind, but in principle would also apply to the use of a C-MAC D blade.

Eat your SALAD.

One of the potential downsides to video laryngoscopy is camera obstruction with blood or vomit. This is especially feared with use of a hyperangulated blade that cannot be used as a direct laryngoscope as backup if the camera fails. 

Dr. James DuCanto is an anesthesiologist who developed the SALAD technique (Suction Assisted Laryngoscopy Airway Decontamination) to prevent airway contamination in such situations. 

Specifically, the technique involves the following steps:

  1. Start with your rigid suction device and decontaminate the oropharynx.
  2. Use the rigid suction catheter similarly to a wooden tongue depressor to lift the tongue and assist with laryngoscope insertion. Continue with airway suctioning. 
  3. Insert your laryngoscope blade, identify airway anatomy, and obtain optimal view. Remember to “stay high and dry,” always leading with your suction and keeping your VL out of the way of blood or vomit. 
  4. Once the desired view is obtained, reposition the suction catheter to the left of the laryngoscope and park it within the esophagus. 
  5. Deliver the endotracheal tube (ETT). 

Don’t take my word for it, watch Dr. DuCanto and others demonstrate the SALAD technique: HERE and HERE

Watch what you’re doing. 

Some are tempted to keep their eyes solely on the video monitor during hyperangulated VL. This is dangerous, as you can cause serious injury to the patient’s teeth, soft palate, tonsillar pillars and even damage or rupture the ETT cuff. Instead, employ a “look down, look up” approach: 

  1. Look down in the mouth, insert the blade midline, and then advance the tip into the vallecula.
  2. Look up at the screen, and then lift the epiglottis for a view of the larynx. 
  3. Look down in the mouth, and then introduce an endotracheal tube alongside the blade. 
  4. Look up at the screen, and then complete the intubation. 

Make room.

Sometimes the handle of the blade may bump into and be physically restricted by the patient’s chest, making it challenging to even advance the laryngoscope into the oropharynx. This can be overcome by inserting the laryngoscope obliquely or at 90 degrees. If we consider the traditional midline insertion site to be oriented with the chin at 12 o’clock, this would mean inserting the blade with the handle oriented toward the 9 o’clock or 3 o’clock position. Once the blade is advanced into the oropharynx, there should then be sufficient room to rotate back to the 12 o’clock position and continue advancing the blade.

Figure 1. Alternative insertion technique. A) Introduce the blade of the GlideScope® at 90 degrees. B) Once in the oropharynx, rotate the handle back to the 12 o’clock position. 

While the midline approach with hyperangulated VL is recommended to obtain an optimal view, occasionally the patient’s mouth opening may be too small or tongue too large to facilitate introduction of the ETT with a midline approach. A few ways to overcome this include inserting the blade slightly to the left of midline (Fig 2), or after inserting midline then shifting the entire handle to the left to make room for the ETT.

Figure 2. Laryngoscopy and view of the larynx as seen on the GlideScope® video screen. A) Introduction of the blade of the GlideScope® along the midline of the tongue. B) View of the larynx when approached at the midline. C) Introduction of the blade of the GlideScope® nearer to the left corner of the mouth. D) View of the larynx when approached nearer to the left corner of the mouth.

Perfect is the enemy of good.

Deliberately restrict your view. This may sound counter-intuitive, as we’re taught to obtain a Grade 1 view (G1v) whenever possible. However, the mechanics of DL and hyperangulated VL are such that while a G1v can facilitate DL, it may sabotage hyperangulated VL by increasing the difficulty of passing the ETT. If the blade is placed too deep, the camera will be in close proximity to the glottic opening, likely giving you a fantastic view. However, it creates a very steep angle at which the ETT must be delivered, and it reduces the amount of real estate on the screen with which to view and correct ETT delivery. By backing up 1 – 2 cm, you will widen the overall field of view, improve alignment of the ETT tip with the trachea, and reduce the angle of approach the ETT must make (Fig 3).

Figure 3. How the glottic exposure changes with pullback or retraction of the video laryngoscope. A) Deeper insertion of the blade can lead to B) a fantastic G1v that may actually impede ETT delivery. C) Retraction of the blade by 1 – 2 cm can lead to D) a restricted Grade 2a (G2a) view that can facilitate ETT delivery. 

The 50:50 rule is a principle that encapsulates this concept: you should aim for a view with hyperangulated VL that achieves a POGO (percentage of glottic opening) of less than 50%, and keeps the glottic opening in the top 50% of the screen (Fig 4). Indeed, sometimes it may be possible to obtain this view with a very proximal placement of the VL at just the base of the tongue, with minimal to no engagement of the vallecula.

Figure 4. Visual representation of the 50:50 rule in the top image: the top 50% of the screen is occupied by the glottic opening, and POGO is <50%. The bottom image results from over-insertion of the hyperangulated VL blade, with eponymous “Kovacs’ Sign,” which is visualization of the cricoid membrane, indicating a steep angle of approach. 

For those that are using the GlideScope®, the length of the LoPro S4 blade and its more distal camera position may result in deeper placement and greater angulation, which could make ETT delivery more difficult as compared to the S3 blade. 

You can watch these resources by airway experts Dr. Richard Levitan, Dr. George Kovacs, and Dr. Richard Cooper for additional detail: 

  1. Levitan on HA VL: HERE and HERE  
  2. Kovacs on HA VL: HERE, HERE, and HERE 
  3. Cooper on HA VL: HERE 

Change your grip.

Holding the ETT closer to the connector (farther from the cuff) will give the operator greater maneuverability and mobility as compared to holding closer to the middle of the ETT (Fig 5). Small movements at this position will translate to greater mobility at the distal end, improving fine motor control and facilitating ETT delivery.

Figure 5. A) Suggested proximal hand placement on the ETT to maximize fine motor control. The proximal end is used to pivot the distal tip toward the glottic opening. B) Traditional mid-ETT hand placement. 

Rotate: Left in the Larynx, Right in the Rings. 

Occasionally, you’ll obtain an optimal view and precise delivery of the ETT to the glottic opening, but then encounter resistance trying to pass through the aperture. Depending on where the hang-up is happening, you can try rotating the ETT. 

If you’re still in the larynx, you’re likely encountering resistance due to the leading edge of the bevel abutting the posterior arytenoid cartilage. Try pulling back about 1 cm and rotating the ETT 90 degrees counterclockwise (leftwards), which will rotate the bevel edge off of the paraglottic structures. Remember, rotate left in the larynx!

On the other hand, if you are encountering resistance past the cords, then this is probably due to the hyperangulation of the stylet and ETT obstructing against the anterior aspect of the trachea and getting caught up on tracheal rings. At this point you can try rotating the ETT 90 degrees clockwise (rightwards) to align the inclination of the ETT and bevel with that of the trachea. Remember, rotate right in the rings!

Figure 6. Demonstration of 90 degree rightward rotation of the ETT. With an overhand grip, the operator can continue to advance the ETT by pushing off of the stylet.

Figure 7. 90 degree rightward rotation of the hyperangulated ETT improves alignment of the ETT with inclination of the trachea. 

Pop it and drop it. 

If you’re still encountering resistance, consider the hyperangulation and change in shape to the distal ETT that occurs from the rigid stylet. You can pop the stylet with your thumb out by about 3 – 5 cm, which should soften and straighten the distal edge, allowing smoother passage of the ETT (Fig 8).

Figure 8. Use of the thumb to extract the stylet 3 to 5 cm to facilitate passage through the vocal cords

Pull towards the feet. 

Once the ET tube has been successfully advanced through the cords, remove the rigid stylet by pulling it out and down toward the patient’s feet (Fig 9). This follows the shape of the stylet resulting in its smooth removal without risk of trauma or ETT dislodgement. 

Figure 9. A) Optimal course over which to direct the stylet for gentle removal by pulling towards the feet. B) Removing the stylet in the vertical plane, pulling toward the ceiling, can lead to trauma or ETT dislodgement.

The Debrief

Hyperangulated VL is a fantastic weapon in our armanament, but comes with its own unique set of challenges compared to DL. Use the tips below to step up your next hyperangulated intubation. 

  1. Lead with suction, employ the SALAD technique, and stay high and dry with your VL to avoid obstruction of the camera by secretions, blood, or vomit. 
  2. Look directly at the patient when initially inserting your laryngoscope blade, then again when delivering the ETT to avoid injuring the patient or damaging the ETT. 
  3. Try inserting the blade with the handle oriented at the 9 o’clock position or obliquely to avoid getting caught up on the patient’s chest with your laryngoscope handle. 
  4. Try a leftward approach with the laryngoscope blade for the patient with a very small mouth opening or large tongue to make room for the ETT. 
  5. A G1v may make ETT delivery more difficult. Try backing up with your hyperangulated blade to deliberately restrict your view. 
  6. Remember the 50-50 rule: the glottis should occupy 50% of the screen, and the POGO should be <50%. Try a shallow insertion of your VL blade, engaging just the base of the tongue. If using the GlideScope®, consider using a LoPro S3 blade instead of the S4 to avoid over-insertion. 
  7. Grip the ETT closer to the distal end to improve maneuverability.
  8. Rotate left in the larynx to avoid hang-up on the posterior arytenoids, and rotate right in the rings to more closely follow the inclination of the trachea. 
  9. Try popping the rigid stylet with your thumb and removing it by 2 – 3 cm to improve ETT passage through the cords, if meeting resistance.
  10. Remove the rigid stylet by pulling down toward the patient’s feet to avoid injury or ETT dislodgement.

References

  1. Bacon ER, Phelan MP, Doyle DJ. Tips and Troubleshooting for Use of the GlideScope Video Laryngoscope for Emergency Endotracheal Intubation. Am J Emerg Med. 2015;33(9):1273-1277. doi:10.1016/j.ajem.2015.05.003
  2. Levitan RM. Tips for Using a Hyperangulated Video Laryngoscope. ACEP Now. https://www.acepnow.com/article/tips-for-using-a-hyperangulated-video-laryngoscope/. Published December 17, 2015. Accessed May 30, 2021. 
  3. Gu Y, Robert J, Kovacs G, et al. A deliberately restricted laryngeal view with the GlideScope® video laryngoscope is associated with faster and easier tracheal intubation when compared with a full glottic view: a randomized clinical trial. Une vue laryngée délibérément restreinte à l’aide du vidéolaryngoscope GlideScope® est associée à une intubation trachéale plus rapide et plus aisée qu’une vue glottique totale: une étude clinique randomisée. Can J Anaesth. 2016;63(8):928-937. doi:10.1007/s12630-016-0654-6
  4. Cho JE, Kil HK. A maneuver to facilitate endotracheal intubation using the GlideScope. Can J Anaesth. 2008;55(1):56-57. doi:10.1007/BF03017601
  5. Neustein SM. Advancing the endotracheal tube smoothly when using the GlideScope. Can J Anaesth. 2008;55(5):314-315. doi:10.1007/BF03017214

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