Tag Archive | "glidescope video laryngoscopy"

See Cords Around Corners

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I knew it was going to be a tough intubation. He was a bear of a man, well over 300 pounds. But compounding the problem was his tiny mouth and diminutive jaw—barely enough mandible to catch on the top of his C-collar. Respirations were agonal and sats were on the verge of precipitous decline. As I scissorred open the teeth, I was dreading the expected view of redundant tissue, blood and saliva, and hoping for the elusive larynx.

The adult Glidescope blades come in two sizes, a 3 and a 4. The 4 is what I use for nearly all adults and is listed as 90 pounds and up. Image Courtesy Graham Snyder, MD

I placed the 4 Mac into the mouth, but it was not good. The man’s jaw and mouth were barely large enough to place the blade between the teeth, yet his tongue seemed gargantuan. The thickness of his torso plus the very real fear of worsening a possible c-spine injury resulted in a view of only a pink wall of tissue.

“Want me to get the scope?” queried the respiratory therapist.

“This is not a candidate; there’s too much blood,” I responded, envisioning the futility of attempting to snake a tiny flexible fiberoptic wire through the patient’s nose or into his mouth–the tissue compressed flat in his supine position and the tiniest droplet of blood or saliva leading to complete loss of view.

“Not the flexible fiberscope, the video laryngoscope,” The respiratory therapist clarified as he placed the plastic blade in my hand and turned the video screen in my direction.

I had picked up the Glidescope a number of times at conferences when walking by promotional booths. On a dry plastic mannequin head, it seemed to work spectacularly. The view of the cords was superior to all but the easiest of direct laryngoscopy, and the force needed to obtain that view was a fraction of that needed normally.

But would it work in a high-pressure, high-stakes clinical setting?

The patient was difficult to bag so I had about 60 seconds before I would need a rescue device or proceed to cricothyroidotomy.

I gently inserted the blade sliding down the center of the tongue and in seconds was greeted with a textbook view of not only the larynx, but the arytenoids and the aryepiglottic folds as well! There was four times the amount of information I needed to place an ET tube normally. I grabbed the endotracheal tube, which the RT had preloaded on the strange glidescope stylet, not knowing that my challenge had just begun.

For the past 11 years, I’ve been giving lectures on management of the difficult airway to the right students at the wrong time in their career. Learning direct laryngoscopy and effective placement of an endotracheal tube is a challenge in itself. When you add the extreme stress and anxiety of a horrifically unstable patient, it’s a wonder we can pull it off at all. However, with the combination of good lectures, operating room and/or simulation time, we all learn the art. Once you become proficient, in truth, it’s not that hard…except when it is.

The majority of difficult airways occur because of an inability to visualize the vocal cords. Usually, this is not a surprise. The causes are innumerable and sometimes additive. Even before beginning the procedure, when a patient has a small mouth, a large tongue, and a short jaw, you should anticipate a difficult airway and make plans for managing it.

There are plenty of other options, including lighted stylets, retrograde intubation and LMAs. The most important thing is that you be well practiced in the technique so that when the time comes, when the stakes are the highest, you are relaxed, confident and proficient.

This is just as true when using video laryngoscopy, and is often ignored because at first glance it seems both very similar in the technique we are all confident in (direct laryngoscopy) and is easier than direct laryngoscopy. This is true, BUT if you do not make the appropriate modifications to your technique, you will at best struggle and at worst have a failed airway.

Video laryngoscopes allow for spectacular visualization of the larynx often in cases where direct laryngoscopy would be extremely difficulty or impossible. This is best demonstrated by a patient with a small mouth and big tongue, which unfortunately is the case with all infants.

The magic of the Glidescope is you do not have to physically look in the mouth (only at the video screen), so intubation can still be accomplished on these tiny airways as demonstrated below in this 16-month infant simulator. See the video and photograph below.

Intubation can still be accomplished on tiny airways, as demonstrated in this 16-month infant simulator. Photo Courtesy Graham Snyder, MD

Click here for video.

Step 1: Know your Equipment.
There are a variety of different video laryngoscopes, each of which have its own unique performance characteristics. At our institution, we use the Glidescope Ranger. But no matter what you use, you must learn the unique geometry of the blades and significantly different techniques for intubation before the time of crisis. This can be accomplished with a stable patient and bedside supervision with an experienced practitioner—and ideally complemented by both supervised and independent practice using human patient simulators or airway task trainers.

Step 2: Assemble the Equipment Correctly.
There are really only three pieces of equipment. The wand (light source and fiberoptic camera), the plastic blade cover and the video screen. The wand plugs into the video screen intuitively and then the blade cover slides onto the wand with a definitive click. The wand must go in straight into the plastic sheath. If the wand is placed into the blade cover rotating 90 degrees, the screen will be 90 degrees off but in addition there will be extremely distracting glare. Make sure that the writing on the blade cover aligns with the writing on the wand. If you don’t, when you look in the mouth you will not be able to tell whether the blurry spots on the video screen are from saliva obscuring the view or from the plastic refracting.

Step 3: Don’t Look in the Mouth.
The Glidescope looks very similar to a Macintosh laryngoscope, leading people to mistakenly attempt to use it as one but everything is different. For one, the basic maneuver is more of a gentle straight up lift than the diagonal forward movement used in direct laryngoscopy. Also, much more importantly, getting the camera to find the cords has nothing to do with the maneuver needed to directly visualize the cords. Keep your eyes on the camera once you are inside the mouth and guide the video screen toward the cords.

Step 4: Use the Steel Stylet that Comes with the Glidecope.
You will be advancing the tube around and over the tongue and must maintain the curve of the original stylet or else the tube will not be able to find the larynx. If you use a normal stylet, it will get straightened out by the time you get to the larynx and will repeatedly, (and extraordinarily frustratingly) pass into the esophagus. You will no longer have the angle needed to pass into the cords.

Correct Technique

Incorrect Technique

Step 5: Don’t Get too Close to the Cords.
The temptation when using the Glidescope (because you obtain such a gorgeous video of the cords) is to press the camera close to the larynx. If the larynx fills the entire video screen, then the tip of your blade is millimeters away from the larynx. However, wherever the camera is, the tube will come in just below that point so if you’re abutting the cords already, when you pass the tube it will pass just below the cords (into the esophagus). If, however, you back away a little from the cords, then, because of the angle of the stylet, once the tube passes in front of the blade it will angle up and smoothly in between the cords.

Incorrect Technique

Correct Technique

Step 6: Back the Stylet out while Advancing the Tube.
The stylet is quite rigid steel and has nearly a 90-degree curve in it. This works perfectly for making the turn around the tongue and effortlessly going through the cords. However, since the trachea does not have a curve in it, as soon as the tip of the tube is placed between the cords, the stylet must be backed out to allow it to pass. Conveniently, there is a little flip top on the end of the stylet perfectly positioned for your thumb to kick it back and the tube to slide into the trachea. This is not optional. It is physically impossible to pass the tube with the stylet in place, so once the tip is between the cords, you or your assistant must remove the stylet.

Remove the stylet to secue the airway. Photo Courtesy Graham Snyder, MD

Conclusion
In my difficult case, once I took the respiratory therapist’s suggestion, I found the trauma patient’s vocal cords in seconds and with a sigh of relief advanced the tip of the orotracheal tube between the cords. I was puzzled briefly by the resistance I felt when I attempted to advance the tube, when the paramedic who brought the patient in (who was also watching the screen) reminded me, “You have to remove the stylet or it won’t advance.” He leaned forward, and like lighting a Zippo, he flicked the stylet lever (see image at left) backwards and the tube effortlessly advanced securing the airway.

When properly used, the video laryngoscope can transform extremely difficult intubations into nearly effortless lifesaving maneuvers and can be used in easy intubations as a safe and controlled way to teach the art and the science of orotracheal intubation.

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Graham E. Snyder, MD FACEP

Graham E. Snyder, MD, FACEP, is medical director for the Center for Innovative Learning at WakeMed Health and Hospitals.

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The Video Laryngoscopy Movement

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By John Allen Pacey, MD, FRCSc

In 1829, the first known device for direct laryngoscopy was invented by British physician Benjamin Guy Babington. Later, the work of the widely recognized father of laryngology, Manuel Garcia, led to the first mirror laryngoscope prior to 1849, with a light source later introduced by Alfred Kirstein in 1895.(1)

In the century since then, the devices available to view the larynx have gone through many evolutions. Most devices have been difficult to use, and injuries related to failed or delayed tracheal intubation have resulted. Recognizing that optimal airway management involves the direct visualization of the airway during intubation, modern direct laryngoscopy has produced different blade lengths, prisms and fiber-optic light channels. However, the emergence of video capabilities in the surgical suite was perhaps the most significant step in laryngoscopy development.

Video laryngoscopy systems provide a clear picture of the larynx and vocal cords on a display monitor, enabling control of the endotracheal tube (ETT) in its trajectory toward the airway. This type of clearly displayed view facilitates fast, accurate ETT placement in difficult airways, preventing complications resulting from improper tube placement.

Other advantages of video laryngoscopy compared with older, fiber-optic systems are substantial. Video images are easily stored on servers and low-cost SD cards, and can be transmitted to other users, allowing for remote recording of activity, skills coaching and quality assurance reviews. The use of Internet display is easy either with real-time transmission or by display of the captured images, so that the captured sequences can be used for teaching purposes to improve the skills of many. As HDTV technology improves, so will the image quality of video laryngoscopy. Last, video laryngoscopic techniques are easier to master than those necessary for direct laryngoscopy, an important factor in its successful use by personnel working in less-than-optimal circumstances.

Initial advocates of video laryngoscopy were anesthesiologists in Vancouver, Canada, who performed intubations daily. Such luminaries as Richard Cooper, BSc, MSc, MD, FRCPC; John Doyle, MD, PhD; and Ron Walls, MD, raised questions about the viability of direct laryngoscopy compared with video laryngoscopy and sponsored the adoption of the technology in other areas of the hospital, such as the emergency department (ED) and the ICU. While recognizing the expense of adding the video component, Cooper in particular has commented that video laryngoscopes are “more robust and resistant to damage.”(2) Adoption in EDs and ICUs has been rapid, and it seemed only a matter of time until video laryngoscopy was introduced into prehospital medicine.

The Need in the Field
The literature shows that intubation performed in an out-of-hospital emergency environment carries with it a higher rate of complications and death.(3) Rapid sequence intubation (RSI), called for by Rosen and others, initially appeared to be effective when coupled with direct laryngoscopy (97% in some reports).(4) But optimism dissipated when a 2003 San Diego study reported that 45% of “easy” or successful intubations carried out on head-injured patients were associated with hypoxemia or bradycardia.(5)

In pediatric patients, the literature shows a need for improved methods. A 2000 San Diego study of 305 pediatric patients showed a success rate of 57%, esophageal intubation of 2% and displaced ETT of 15%.6 An older study, from 1989, reported a 50% success rate in children one year in age or younger.(7)

The reasons for these failure rates are obvious to anyone who has worked in the field: the variable intubation skill levels among EMS personnel and adverse conditions, such as weather, limited lighting, foreign bodies in the airway and trauma (leading to hemorrhage and distorted anatomy). Because direct laryngoscopy in these conditions continues to be fraught with difficulty, EMS medical directors are reconsidering their airway management protocols. Although it’s clear some EMS personnel are able to overcome the deficiencies of direct laryngoscopy and produce acceptable results, the failure rates have provoked questions of whether direct laryngoscopy has become a “legacy technique,” introduced when there were no alternatives.(8)

GlideScope in Use
In 2001, the GlideScope® was introduced as the first commercially available video laryngoscope. The device was designed with the recognition that a camera positioned away from the tip of the device would provide the best perspective and enhance visualization. The 60º angle allows for 99% Grade 1 and 2 views.2 Another significant design feature is the device’s unique anti-fog component, which reduces lens contamination.

The GlideScope Ranger single-use laryngoscope—designed to eliminate the need for disinfecting the blade for fast-paced intubation settings—is being used in Iraq and Afghanistan. The backpack-sized, rugged and shockproof version of the original device with an antiglare screen was trialed at the R. Adams Cowley Shock Trauma Center, Fort Sam Houston and Andrews Air Force Base. Following successful trials of the device at these world-renowned medical facilities, the Ranger was deployed in hospitals and combat settings.

In particular, a number of reports from the Canadian Expeditionary Hospital in Kandahar, Afghanistan, involve the management of bloody airways, intubation around expanding hematomas and other challenging ETT exchanges. The Ranger is also in trials with Whatcom County (Wash.) EMS, where the early results are encouraging, according to Medical Director Marvin Wayne, MD.

Aeromedical applications, notably in helicopter environments, are also under study with the GlideScope Ranger. It’s notable that first-time aeromedical users had a high success rate even in the most adverse conditions. Reports of Ranger intubation under unusual conditions include two intubations prior to extrication from crushed vehicles, in flight re-intubation, and in-flight primary intubation (where direct laryngoscope use is limited).

A Look Forward
There’s considerable pressure on EMS to improve successful intubation rates, and the advent of video laryngoscopy designed for the field is poised to produce findings that support its use in this demanding context. How extensive a role this technology will play is complicated by the debate over whether intubation—considered the gold standard in anesthesia practice—is necessary for all compromised airways. EMS personnel work with patients who are often treated under adverse conditions, and there will always be a need for difficult airway management in the trauma setting. A growing amount of evidence supports the view that video laryngoscopy will be a standard in that setting, but more studies are needed before it’s an established reality.

As for speculation about the future of video laryngoscopy in the prehospital setting, aeromedical studies will likely continue to demonstrate the efficacy of RSI using video laryngoscopy. It’s felt that “time on the ground” can be significantly reduced by the use of video laryngoscopy-assisted RSI, either pre-flight or in-flight. Also, many feel RSI coupled with video laryngoscopy will be shown as the most effective strategy for prehospital intubation management, which will likely involve development of supraglottic airway technology.

The cost of failed or difficult intubation can be very high as reflected in a private settlement in excess of $15 million in 2002.(9) There’s also the cost associated with emotional burden to the providers involved, who may face insurmountable obstacles to care.

The added value of video recording will allow medical directors to more accurately measure personnel competency and skill success rates, document the depth of ETT insertion and enhance education. Overall, these devices can aid emergency airway management and likely lead to better patient care—a universal goal of all EMS providers.

References
1. Proceedings of the Royal Society of London. vii:399–410, 1856.
2. Cooper RM, Pacey JA, Bishop MJ, et al: “Early clinical experience with a new video laryngoscope (GlideScope) in 728 patients.” Canadian Journal of Anaesthesia. 52(2):191–198, 2005.
3. Murray JA, Demetriades D, Berne TV, et al: “Prehospital intubation in patients with severe head injury.” Journal of Trauma. 49(6):1065–1070.
4. Bulger EM, Copass MK, Maier RV, et al: “An analysis of advanced prehospital airway management.” Journal of Emergency Medicine. 23(2):183–189, 2002.
5. Dunford JV, Davis DP, Ochs M, et al: “Incidence of transient hypoxia and pulse rate reactivity during paramedic rapid sequence intubation.” Annals of Emergency Medicine. 42(6):721–728, 2003.
6. Gausche M, Lewis RJ, Stratton SJ, et al: “Effect of out-of-hospital pediatric endotracheal intubation on survival and neurological outcome: A controlled clinical trial.” JAMA. 283(6):783–790, 2000.
7. Aijian P, Tsai A, Knopp R, et al: “Endotracheal intubation of pediatric patients by paramedics.” Annals of Emergency Medicine. 18(5):489–494, 1989.
8. Cooper RM: “Is direct laryngoscopy obsolete?” Internet Journal of Airway Manage­ment. Vol. 4, 2006–2007. www.adair.at/ijam/volume04/specialcomment01/default.htm
9. Law Offices of Wade E. Byrd, P.A. 232 Person St. Fayetteville, NC 28301.

Disclosure: The author is the inventor of the GlideScope, and president and research director for Verathon Medical Canada, the makers of GlideScope systems.

This article originally appeared in The Perfect View.

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