You might remember Minh Le Cong from the needle vs. the knife – part I podcast. He is a retrieval (EMS) physician from down under and he has a particular interest in prehospital airway management. He was kind enough to review the king vision video laryngoscope for the blog. Neither Minh nor myself have any conflicts of interest with this company. This is the device that Cliff Reid has been keen on as well. If you are an ED doc in a shop that doesn't have difficult airway equipment, this would seem the ideal device to buy for yourself as well. Now on to Minh's review…
Brief Review of the King Vision Video Laryngoscope
by Dr Minh Le Cong
The King Vision video laryngoscope is the latest in a long series of devices that claim to provide the “perfect view” for intubation via use of video and digital technology. I chose to purchase one to test it, having personally reviewed a number of the major players earlier this year at an airway conference in Australia. I am a rural generalist medical practitioner working in Cairns , Queensland, Australia for the Royal Flying Doctor Service, the longest continuously running aeromedical service in the world. My primary medical specialist training was in rural and remote medicine with subspecialty training in emergency medicine and internal medicine. My clinical work is a mix of aeromedical retrieval and remote medicine. I was not sponsored by anyone to write this review and purchased the device for personal use.
The King Vision Video laryngoscope is a two piece design. It has a reuseable monitor that attaches to disposable blades. In some respects this is a similar approach to the Pentax Airway Scope which has a reuseable monitor and disposable blades. Where the King Vision differs is that the LED light and CMOS camera are mounted on the disposable blades. This makes the design simpler to use as you essentially just have to connect the two pieces together by simply sliding them into each other.
The blades are all Macintosh #3 size and compared to a normal Macintosh #3 bladed laryngoscope, the King Vision blades appear wider and shorter. There are blades with a guiding channel and standard blades without. Both only come in #3 size though .The guide channel blade is very similar to the Pentax and Airtraq blade designs. . When you use the device you quickly come to the conclusion that all you will need is a #3 size blade.
The display is an OLED design of surprisingly good clarity and resolution when you consider the pricing of the device ( see Cost section below). It is turned on with a single power button on the back of the display and turned off by depressing it for 3 seconds. It is certainly a no frills design which makes it simple to understand and use. There is no brightness adjustment nor in built video recording function. There is a mini USB port for a video out function to either a display or digital recorder. The LED light on the blade tip is very good with nice intensity and a pale white illumination. The device is powered by standard AAA size batteries x 3 and is rated to last at least 90 minutes or greater.
My colleagues and I tested the device using a Trucorps Air Sim intubation mannikin, using size 6 and 7.5 cuffed endotracheal tubes as well as a Frova bougie. We compared it to direct laryngoscopy with a Macintosh #3 blade. We tested using standard intubating conditions and simulated difficult intubation by inflating the mannikin tongue to simulate swelling and upper airway obstruction. We conducted the testing indoors with normal fluorescent tube lighting and then outdoors in midday sunlight. As expected in the simulated difficult intubation the King Vision performed significantly better than direct laryngoscopy, both in terms of laryngeal visualization but also speed and success of intubation. There were some initial learning issues with passing the tracheal tube via the guide channel but these were quickly mastered within 3 practice intubations.
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The finding that most impressed me about the King Vision was using a bougie with it. You can use the bougie with or without the aid of the guide channel and getting the tip pass the cords is much easier using the video laryngoscope. Then passing the ETT over the bougie under video guidance is a major advantage as you can see how the tip of the ETT catches on the right arytenoids.
[click images to see full size]
Okay those images were of course of the indoors testing. Here are the results of the outdoor testing. Remember this is relevant for the prehospital work we do in RFDS as sometimes you are outdoors doing RSI at a cattle station for someone who has fallen off a horse and sustained a severe head injury!
Here is my colleague Dr Shaun Parish, performing the testing outdoors. Note the bright sun light. Direct larynogoscopy interestingly performed fairly well in this testing which is probably because we did not have the mannikin directly on the ground. When trying to intubate a person flat on the ground with bright sunlight we have usually found this quite difficult due to the glare of the sun into the field of view particularly if directly coming from behind. The King Vision performed well even in this brightly sunlit setting with little difference to performance indoors. It was difficult to get a good picture of the LED screen view during intubation so the best I could do was take out the King Vision and point it at an object and take this photo in direct sunlight from behind. You can see the image although degraded and washed out of colour is still an effective resolution with clearly discernible structures.
[click images to see full size]
Now there has been one published study finding the Pentax AWS screen does not perform well in bright outdoor conditions and I was aware of this so it surprised me that the King Vision was more capable in this setting.
Pricing and Overall package
The King Vision is sold by Critical Assist in Australia for the delivered price of $1100 approximately. This is what you get for that money.
A kit with the monitor display and 4 disposable blades ( 3 channeled and 1 standard). The monitor has a 1 year guarantee and the disposable blades can only be bought in boxes of 10 at $30each.
Bottom line for me
This is the best overall package for getting started in video laryngoscopy due to low pricing, quality imaging and simplicity of use. It is excellent I think for prehospital airway management having a display that performs well in outdoor testing. Its closest rival would be the AV laryngoscope distributed by LMA Pacmed in Australia but that costs approx $7000 each. Another close rival would be the Airtraq by Prodol which is cheaper and disposable but has the disadvantage of using a shielded eyepiece as the viewing display. With the King Vision you can maintain an overall view of the patient without having to lean down and peer into a black hole. Therefore you can maintain situational awareness and keep an eye on oxygen saturation monitor and cardiac rhythm as well as anterior neck and chest whilst getting that “perfect view”! I think the expense of previous video laryngoscopes has made most airway providers resist the jump into learning the skill of this new technique but now with the King Vision there is little barrier to make that leap of faith! It costs less than most airway courses!
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- EMCrit 293 – The Jerk & Check, Functional Heuristics in Resuscitation Project (MotR) - March 3, 2021