by Mike Steuerwald and Tyler Winders
Let the record show, this is not a debate for or against the use of video cameras on laryngoscopes. It’s not really a debate at all. It’s a plea. An honest plea…
The “DL vs. VL” debate has been had. It will continue to be had as our research evolves and our tools evolve (and we will participate). But, I beg of us as a community to pause and collectively consider a point of order: our discussion and debate, and worse our education of novice critical care providers, and even worse our research, is becoming marred by the fact that we aren’t all speaking the same language. We often throw around terms without RIGOROUS attention to detail.
As Kleenex is to facial tissue, “Video Laryngoscopy” has become a descriptor for any use of any laryngoscope device with a video camera on it. We will respectfully submit that this is inappropriate and makes conversation, education and interpretation of research challenging. We can not continue to use the term “Video Laryngoscopy” without METICULOUS attention to clarifying if we are speaking in terms of Direct Laryngoscopy (DL) devices with video cameras on them OR in terms of Indirect Laryngoscopy (IL) devices with video cameras on them.
At this point you might be asking, “Why should we care, and what are you talking about?”. Fair point. Let us digress…
As Reuben Strayer discusses in PHARM podcast 104, when the use of video cameras on laryngoscopes first became popular in emergency airway management, the tools were indirect in their nature. Defined simply, IL is the use of an optical instrument to visualize the glottis WITHOUT creation of a straight line of sight from the operator’s retina to larynx. This instrument can utilize any means for viewing the glottis that the designers choose (e.g. optical lenses, mirrors, or video cameras on the end of hyper-angulated blades – video cameras obviously having become far and away the most popular modality).
Today, the term “Video Laryngoscopy” is not synonymous with “camera facilitated” IL. Video cameras are popularly being used to augment direct laryngoscopy (DL) as well. These instruments place video cameras on blades that retain “standard geometry” (another of Dr. Strayer’s terms from PHARM 104). These standard geometry blades are meant to align the airway curvature into a shape where a line-of-sight can be had from outside the mouth straight to the glottis.
DL is not without its shortcomings, with or without a camera involved. IL is not without its shortcomings. Can an operator using a DL device with a built in camera avoid common pitfalls of IL device? Maybe…I don’t know if we as a specialty are ready to answer that question. Can an operator using an IL device gain an advantage over a DL device with a camera built in? Maybe…I don’t know if we as a specialty are ready to answer that question either.
Specifically addressing education, DL devices with a built in camera are useful in that they allow for trainees in teaching hospitals to effectively receive real time feedback on their efforts. They also allow for supervising physicians to have ultimate situational awareness. For this to be worth anything, we must ensure that trainees recognize DL is a technique with specific muscle movements and IL is a technique with specific muscle movements. We must not allow trainees to think that the presence or absence of a camera on a blade shaped like a Mac 3 changes the way you wield it in your hand. This, I think is the reason that some research has demonstrated that Macintosh shaped devices without cameras performed poorer than Macintosh shaped devices with cameras.
So who should be using video cameras? We think everyone, but this isn’t a debate on that subject as promised. All we ask is that if you cite a use of the CMac in a presentation, or in a blog post, or in research, you state whether the use was with a standard geometry blade or with a hyper-curved blade. We make the same plea for the Glidescope product, or for any other producer of these tools (note: we don’t support any one brand vs. any other). When a colleague asks for the C-Mac, please prompt, “With what blade?” When a medic says, “I used a video laryngoscope,” please state, “I’m not sure what you mean exactly…do you mean a hyper-curved blade?” When your resident says, “I plan to use VL for this tube,” please inform them of the death of that term, have them send their condolences, and ask if they would like to do “DL with a camera or IL with a camera” and start a discussion on why one technique might be more to your advantage than the other.
We invited some of our FOAM colleagues to comment on the post prior to publication, take a look below to read their comments, and feel free to add your opinion in the comment section below.
What do you think? Does "Video Laryngoscopy" need to Die?
Peer Review Comments
My immediate impression is : "So what?"
If a resident tells you they drove to work, do you ask them "How did you do that?"
Does it matter if they used an automatic vs manual transmission, truck vs sedan, petrol vs diesel, GPS vs non GPS aided?
Having interviewed Dr Pacey the inventor of the Glidescope, I am impressed by his intelligent arguement for video laryngoscopy, in particular with hyperangulated designed systems. I also appreciate your arguement for having standard geometry blade systems with video capability for teaching and supervision of DL technique.
I actually dont see an issue with the term video laryngoscopy. I see the issue is with market driven confusion of a product that has several designs. I also dont see how changing the terminology is going to help. We all seem to use the term VL easily and without too much challenge and even published research always defines the specific device tested. The only time it seems to be an issue is when folks start debating about what is the better/superior device.
When that occurs, just remember that is driven by market forces rather than true clinical need, so caution must be exercised. Every high end system now caters to all needs with both standard geometry and hyperangulated blades.
I think I mostly agree with Minh. Nothing wrong with the term VL if it's used correctly.
I see these terms as having quite specific meanings:
- DL means you're looking into the mouth.
- VL means you're looking at the screen (at least for the final tube delivery maneuver).
- VL is synonymous with indirect laryngoscopy.
A traditional laryngoscope has no camera, therefore a direct line of site must be established between the eye and glottis, therefore all traditional laryngoscopes use standard geometry blades, and the operator always performs DL with a traditional laryngoscope.
When you put a camera on a standard geometry blade, you can do VL or DL. I find this to be a huge advantage of standard geometry blades over hyperangulated blades.
All hyperangulated blades require video because you cannot do DL with a hyperangulated blade. The advantage of the hyperangulated blade is that glottic visualization can often be accomplished more easily and with less force; the price you pay is more difficult tube delivery.
Standard geometry and hyperangulated geometry are not binary categories, a blade can be slightly or greatly hyperangulated. the more hyperangulated the blade, the easier glottic visualization and less force needed to visualize the glottis, but the more difficult tube delivery (and the more different the skillset needed, vs. intubating with a standard geometry blade).
There is some confusion that arises with these terms:
- Folks often use the term video laryngoscopy to refer to hyperangulated blade geometry. You can do VL with standard or hyperangulated geometry.
- Folks use Glidescope to refer to hyperangulated geometry video and CMAC to refer to standard geometry video. Both Glidescope and CMAC devices now have both standard and hyperangulated geometry blades.
In my view, video laryngoscopy is a huge step forward for a number of reasons, while hyperangulated blade geometry is a comparatively minor advance.
Well, I look at standard geometry VL blades as a P51D fighter - they allow you to do something that is typically done alone - with an experienced backseat observer to instruct you or bail you out. Essentially a DL trainer.
When you start to use the hyperangulated VL blades - you step away from any resemblance of DL into the exclusive realm of VL