Since video laryngoscopes first became available at the start of the millennium they have been increasingly adopted into clinical practise, so much so that in some places the skills of direct laryngoscopy and the traditional methods of managing the difficult airway are becoming a dying art.
The major advantage of video laryngoscopy is the ease in which a view of the laryngeal opening can be obtained using indirect laryngoscopy, where an image from a camera mounted on the laryngoscope’s tip is displayed on a video monitor, in contrast to direct laryngoscopy where the oral, pharyngeal and tracheal axes need to be aligned to allow the intubator to obtain a direct view of the laryngeal opening through the patient’s mouth.
In experienced hands both methods are likely to yield similar results in children with normal airways, however when it comes to patients with difficult airways, video laryngoscopy has the advantage as it allows the intubator to see round the corner, meaning that alignment of the various axes essential for obtaining a good view with direct laryngoscopy (which may not be possible in patients with difficult airways) is not required. Also less lifting force is required to obtain a view with video laryngoscopy where the laryngoscope just slides round the corner, compared to direct laryngoscopy where the tongue and soft tissues must be moved out of the way, meaning video laryngoscopy is generally less stimulating for the patient and may also have a lower risk of airway trauma (particularly in the setting of the difficult airway). Video laryngoscopy also allows all members of the team to see what the intubator is seeing allowing them to better assist with the intubation and also provides a better educational experience for all team members present.
Use of video laryngoscopy is not however without problems and in particular passage of the endotracheal tube can be more difficult as the tube must be directed round the corner using the image on the screen to guide its passage, compared to the straight passage to the laryngeal opening under direct vision with direct laryngoscopy. Also secretions, blood and vomit in the airway cause significantly more problems with video laryngoscopy, than with direct laryngoscopy and in some cases can make intubation with video laryngoscopy impossible. Technical failure is also more problematic with video laryngoscopy as it not so easy to immediately replace a faulty video laryngoscope, compared to the speed and ease at which a faulty traditional laryngoscope can be replaced. Finally considering that it is often direct laryngoscopy that rescues video laryngoscopy when it fails, with increasing use of video laryngoscopy it is concerning that skills in direct laryngoscopy are being taught and practised less frequently, meaning that they may not be available to rescue the situation when they are called upon.
There is no doubt that video laryngoscopy has made management of the difficult airway easier and safer, however video laryngoscopy should not be relied upon to work in every situation and intubation failure must be prepared for by teaching and maintaining skills in direct laryngoscopy and the traditional methods of managing the difficult airway. Likewise to reliably use video laryngoscopy to rescue failed direct laryngoscopy, requires the intubator to gain experience of using video laryngoscopy in patients with normal airways, as the practise of reserving video laryngoscopy for use only in the situation of a difficult airway is likely to be met with failure.
Types of video laryngoscope
Video laryngoscopes can be divided into two main types. Firstly, there are those that maintain the shape of the traditional Macintosh or Miller laryngoscope blade e.g. C-MAC, McGRATH MAC, Medan and Vimed, while the second group of video laryngoscopes have a hyperangulated blade design e.g. Airtraq, GlideScope, King Vision and C-MAC D-blade.
The main advantage of the hyperangulated blade design is an increased ability to see round the corner and therefore they generally provide a better view when dealing with a difficult airway compared to the traditional Macintosh or Miller shaped video laryngoscope blades. However while obtaining an excellent view of the laryngeal opening is normally straightforward with an hyperangulated blade, it is not always as easy to direct the endotracheal tube round the sharp bend into the trachea and the various manufacturers have devised a number of different strategies to deal with this such as channels on the video laryngoscope and hyperangulated stylets.
The video laryngoscopes that maintain the traditional Macintosh or Miller blade design have the advantages of familiarity to those already experienced in direct laryngoscopy and tube passage is generally easier, as a traditionally shaped bougie or stylet can be used, compared to the hyperangulated video laryngoscopes where the curve in the stylet or bougie needs to match the shape of the hyperangulated blade meaning passage into the trachea may be more difficult. Another advantage of these traditional shaped video laryngoscopes is that they can also be used as direct laryngoscopes should there be a technical failure or if secretions in the airway obstruct the view. This function can also be made use of for educational reasons where the student performs direct laryngoscopy without looking at the screen, while the instructor observes progress on the screen offering advice where required.
The Airtraq fits into the hyperangulated class of video laryngoscope, providing excellent views in difficult airways. It overcomes the difficulties of getting the endotracheal tube to the cords by using a channel on its side to help direct the endotracheal tube round the corner and into the trachea. The endotracheal tube is preloaded into the channel and once the view of the laryngeal opening has been centred, the endotracheal tube is advanced from the top of the channel. If the direction of the endotracheal tube needs to be adjusted, up or down movements can be achieved by changing the angle of the Airtraq, and right or left adjustment of the endotracheal tube can be achieved with clockwise or anticlockwise rotation of the endotracheal tube respectively.
The Airtraq is currently available in two version. The Airtraq SP is a low cost, disposable single use device that is available in four sizes covering neonates to large adults. There is also a nasotracheal and double lumen version, however both of these are only available in adult sizing.
The Airtraq Avant consists of reusable optics and disposable blades, bringing down the cost per use, however this is currently only available in adult sizes.
When it comes to viewing options with the Airtraq you are spoilt for choice. The Airtraq comes with an eyepiece and can be used without any additional camera by direct view. This keeps costs down and serves as a useful backup if there is technical failure of one of the other devices.
Alternatively the eyepiece on the Airtraq can be connected to most endoscopy cameras offering the option to display the image on a larger monitor by using technology that is most likely already available in the department.
They have also produced a wifi camera which can be attached to the Airtraq adding convenience of not having to lean over the patient to intubate and the options of recording the procedure or to have the camera display mirrored on a larger screen using the built in wifi.
Another nice feature offered by the App is remote view where the real time camera images can be sent remotely to another person who can also talk to the intubator and offer advice using technology similar to FaceTime.
The big advantages of the Airtraq are its low cost meaning that a difficult airway solution can be introduced to a department for very little initial financial outlay, the flexibility of the viewing options and smart technology offering real time transmission of footage wirelessly to a large screen or to anywhere in the world using the remote view feature. Also the image quality, particularly when using the smartphone adaptor, is on par with the more expensive video laryngoscopes.
Some limitations are that it requires more practice to become proficient with than the traditional shaped video laryngoscopes, as tube placement is not only determined by what you do with your right hand but also by the view you have with your left hand and adjustments of both hands may be required to successfully pass the tube despite a good view. Also the clockwise and anticlockwise rotational movements to adjust the tube position to the right or left don’t come naturally to those already skilled in direct laryngoscopy, however with some practice are quickly learned. Like all video laryngoscopes secretions can cause problems and in small patients there isn’t normally room to fit a yankauer suction catheter down the side of the device, however a flexible suction catheter can be passed down the preloaded endotracheal tube to clear secretions. Finally when learning to use the Airtraq in infants I found the endotracheal tube frequently became caught on the bulky right arytenoid cartilage and to avoid this it is important to firstly make sure you are not to close to the laryngeal opening and I also found it helpful to initially aim toward the left arytenoid until you have got past the right arytenoid and then to rotate the endotracheal tube clockwise into the airway.
Alternatively I have developed a new technique for using the Airtraq in infants where after obtaining a view of the airway, a styleted endotracheal tube is passed into the bottom of the Airtraq’s channel allowing the channel to direct the endotracheal tube round the corner and in the direction of the laryngeal opening. Any fine adjustment of the tube is now independent of the airtraq position and is done using a similar technique to that used with direct laryngoscopy.
In summary the Airtraq is a cheap, smart and flexible intubation device that provides excellent views in difficult airways and with practise allows rapid and confident tube delivery in all ages of children.
Videos of Airtraq use in Children
The GlideScope also fits into the hyperangulated class of video laryngoscope and as a result generally provides excellent views in difficult airways. In contrast to the Airtraq it is a non-channeled device and it therefore requires use of a hyperangulated GlideRite stylet to direct the endotracheal tube round the corner towards the cords. Due to the sharp angle in the stylet it is not normally possible to advance the styleted endotracheal tube all the way into the trachea and the stylet is normally partially withdrawn after passing the tube through the cords, but before advancing the tube into the trachea.
The GlideScope AVL consists of a video monitor connected by a cable to a video baton which is covered in a disposable stat. There are two baton sizes and a range of stat sizes enabling use in all sizes of patient from neonates to large adults. The image displayed on the GlideScope video monitor can also be mirrored on a larger monitor using a HDMI cable. They also offer a light weight, battery powered version the GlideScope Ranger designed to be more portable lending it to use in the prehospital or transport environment.
They have also recently introduced a low profile version of the GlideScope called the Titanium Spectrum which has the added advantage of improved image quality and a low profile design compared to the GlideScope AVL. The Single Use Titanium Spectrum blades connect either via a smart cable to the same GlideScope video monitor used by the AVL system or the GlideScope Go, a small screen can connect directly to the end of the blade without any cables providing an extremely portable and lightweight solution.
The Titanium Spectrum blades as well as offering improved image quality over the AVL system should also offer additional advantages in patients with limited mouth opening. They are available in a range of sizes covering the same patient population as the AVL. As well as the Titanium Spectrum LoPro blades, Verathon also have two MAC blades in a size 3 and 4. They also offer reusable versions of the Titanium blades in both LoPro and MAC design, but only in adult sizes. All options offer built in recording with the exception of the Ranger system.
The main advantages of the GlideScope are the ease at which a view of the laryngeal opening can be obtained, the range of sizes offered and the option of a low profile blade design. Image quality using the GlideScope AVL is similar to the Airtraq’s wifi camera, but is noticeably inferior to that achieved using the C-MAC.
A common complaint with the GlideScope (and shared with other hyperangulated video laryngoscopes) is that while a good view of the laryngeal opening can be easily obtained even in difficult airways, there is not infrequently difficulty directing the endotracheal tube to the cords or due to the shape of the stylet, passing the endotracheal tube into the trachea. The companies own GlideRite stylets help with this to some degree, however control of its tip takes practise, as it is not as easy as a traditionally shaped stylet and tube passage can be difficult in the setting of airway oedema.
Videos of GlideScope use in Children
The King Vision aBlade video laryngoscope consists of a video display connected directly on top of the reusable aBlade video adapter to which the disposable blade is attached. The blades are available in three sizes with the two smaller blades covering use in neonates to 10 years olds fitting onto a smaller video adaptor and the larger size 3 blades (used in children > 5 years old to adults) fitting onto a separate larger video adaptor. Currently the size 2 and 3 blades are available in both channeled and non-channeled options, while the smaller size 1 blade is only available in the non-channeled type. Due to the hyperangulated design, when using the non-channeled blades use of a stylet is recommended.
As the display is mounted directly on the video laryngoscope this makes it very portable. It is powered by three standard AAA batteries which last approximately 80 minutes. The video display can be mirrored on a large screen using their custom video output cable and while there is no built in option to record, this can be done using a third party video capture device.
The King Vision video laryngoscopes main advantages are its low cost, option of channeled and non channeled blades and its portability. Both the image quality and the ease of obtaining a view of the laryngeal opening is similar to the Airtraq wifi camera and the GlideScope AVL. While some may regard the lack of a rechargeable battery as a disadvantage, an alternative view is that the use of AAA batteries eliminates the need to keep the device on the charger when not in use and the use of standard batteries means replacement is straight forward and cost effective. The lack of built in recording will not be a major problem for the average user, however as setting up the third party video capture devices take some time and affects the devices portability, recording may not be possible during an emergency intubation.
Videos of King Vision use in Children
The C-MAC video laryngoscope has the familiarity of a traditional Macintosh or Miller blade shape meaning that it is intuitive to use for those already skilled in direct laryngoscopy. Due to their shape, these blades offer the option to switch from video to direct laryngoscopy (useful for educational reasons and if blood or secretions block the view).
They offer a full range of paediatric and adult sizes and also have a hyperangulated D-Blade which is designed to provide a better view in patients with a difficult airway. The system is available with both reusable and disposable blades which can be connected to either their standard monitor using a cable or the blade can also be attached directly to a small Pocket Monitor adding portability to the range.
There is also the option to connect a flexible fiberoptic scope to the C-MAC monitor at the same time as the video laryngoscope, switching between them at the touch of a button. Like with the systems above, there is the option to mirror the image to a large screen monitor and to record on the device.
The technique for using the traditional shaped Macintosh or Miller blades is similar to direct laryngoscopy and while an endotracheal tube can be passed without use of a stylet or bougie, if you do need to use one a hyperangulated bend is not required and they can be shaped the same as you would do with direct laryngoscopy, aiding tube passage into the trachea. When using the D-Blade a hyperangulated bend in the stylet is required and Storz offer a C-MAC Guide stylet for this purpose.
The main advantage of this system is the ease of use of the traditional shaped blades with the option to switch to the hyperangulated D-Blade for the more difficult airways. When it comes to image quality the C-MAC is excellent, producing beautiful high quality images of the airway. The major downside to this system is cost, which quickly adds up if you need to stock a range of blade sizes covering patients from neonatal to adult sizes and when you consider that the blades will be out of action while they are sterilised after use, this means that stocking more than one blade of each size is often required. While in time the new disposable blades may help address this issue, at present Storz only offer a limited number of their paediatric blades with the disposable system and currently those disposable blades are noticeably thicker than their metal counterparts.
Videos of C-MAC use in Children
The McGRATH MAC enhanced direct laryngoscope has the traditional Macintosh blade shape with a screen attached directly to the video laryngoscope. Like with the C-MAC this allows it to be used for both video and direct laryngoscopy. The disposable MAC blades come in four sizes covering neonates to large adults. They also offer a more hyperangulated X blade, however this is currently only available in a size 3.
The device is the smallest and lightest of the video laryngoscopes described making it incredibly portable. The image quality is similar to that achieved with the Airtraq wifi camera, King Vision and the GlideScope AVL, although in contrast it doesn’t offer the option to mirror the display on a large monitor or to record.
The advantages of the McGRATH MAC are its low cost, portability offered by the built in screen and the ease of tube delivery due to its traditional Macintosh shape. Like the King Vision it doesn’t have a rechargeable battery, but in contrast uses its own custom battery which must therefore be stocked separately. However each battery has a long life lasting approximately 250 minutes and the time left in minutes is displayed on the monitor.
The Medan Video Laryngoscope uses a traditional Macintosh blade design with its screen attached directly to the video laryngoscope. It comes in two sizes – Child (for use with MAC 1 and 2 sized disposable blades) and Adult (for use with MAC 3 and 4 sized disposable blades). Both devices are well balanced in the hand. The original version had a 2.4 inch screen while the newer E.An-II Plus version offers a larger 3 inch screen.
The device is particularly well suited for educational use as the screen can be rotated 180° to the right and 90° to the left allowing the intubator to use the device as a direct laryngoscope, while the supervisor can view the screen from the side offering instruction as needed.
The Medan has a rechargeable battery and built in storage allowing recording of the intubation directly to the device. The image quality is excellent and with their latest E.An-II Plus version image quality is on par with the C-MAC.
The main advantages of the Medan are a small, light, well balanced device with a premium feel that provides excellent images quality with built in recording and a rechargeable battery for a very reasonable price. The only downside is that if you intent to use it for both adults and children then you will need to purchase two devices.
Videos of Medan use in Children
The Vimed Video Laryngoscope uses the familiar Macintosh blade design with a large 3 inch screen attached directly to the video laryngoscope. It provides a solution for intubation of all ages, from preterm to large adult, through the use of two all metal handles – Infant (for use with MAC 00, 0 and 1 sized disposable blades) and Adult (for use with MAC 2, 3 and 4 sized disposable blades). The adult handle can also be used with a more hyperangulated size 3 disposable blade (3D Blade) to provide a more anterior view, which is useful for difficult airways. The Vimed has a removable rechargeable battery allowing the device to always be available, as when empty the battery can simply be replaced with a fully charged spare, while the original battery is then charged.
The most striking thing about the Vimed is just how good the image quality is and it provides the intubator a breathtaking view of the paediatric airway that is without doubt the best of any video laryngoscope I have used. Also the disposable blades for the infant handle are noticeably thinner than the disposable blades used in the other video laryngoscopes making the Vimed easy to use even in the smallest baby.
Videos of Vimed use in Children
Video Laryngoscope Comparison
As you can see each of the video laryngoscopes above have their own individual advantages and disadvantages and which one you choose for your department will depend on your demands and resources. As I’m fortunate enough to have access to all these great tools I’m spoilt for choice, however as a rule I generally prefer using one of the hyperangulated blades when dealing with a difficult airway and a traditional shaped blade when intubating a patient with a normal airway (particularly with nasal intubation where using a hyperangulated blade adds significantly to the difficultly of the procedure in a patient with a normal airway). However to be able to use a hyperangulated blade effectively in a patient with a difficult airway requires practice of its use in routine airways. Likewise it is important not to just learn one device and it is vital to maintain skills in direct laryngoscopy, as when one technique fails (even if you felt it was the technique most likely to succeed) you can rescue it with another technique that is familiar to you.