|Year : 2021 | Volume
| Issue : 3 | Page : 163-167
Tips and tricks to improve videolaryngoscopy skills
Divya Jain1, Rakesh Kumar2, Sunil Kumar2, Anudeep Jafra1
1 Department of Anaesthesia and Intensive Care, Post Graduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Anaesthesia and Intensive Care, Maulana Azad Medical College and Lok Nayak Hospital, New Delhi, India
|Date of Submission||20-Jul-2021|
|Date of Acceptance||28-Jul-2021|
|Date of Web Publication||26-Aug-2021|
Dr. Divya Jain
Department of Anaesthesia and Intensive Care, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012
Source of Support: None, Conflict of Interest: None
Videolaryngoscopes (VLSs) are a promising addition to the difficult airway management armamentarium. These devices utilise video-camera technology to visualise airway structures on a monitor and facilitate endotracheal intubation. They offer an improved view of the glottis without the need for alignment of the oro-pharyngo-laryngeal axes. Today, in the era of the COVID-19 pandemic, there is a need for a shift towards a more cautious and circumspect approach towards airway management. Among the aerosol-generating procedures, endotracheal intubation is especially hazardous. Various protocols and guidelines recommend VLSs as the device of choice for intubating COVID-19 patients. It is thus becoming important that airway managers become adept at using various types of VLSs and troubleshoot problems along the way. We have a plethora of these devices with different configurations and shapes. Through this article, we hope to discuss a few practical troubleshooting tips while using different types of VLSs.
Keywords: Airway management, troubleshooting, videolaryngoscopes
|How to cite this article:|
Jain D, Kumar R, Kumar S, Jafra A. Tips and tricks to improve videolaryngoscopy skills. Airway 2021;4:163-7
| Introduction|| |
The integration of optical image guides and video-cameras into standard laryngoscopes lead to the development of videolaryngoscopes (VLSs). These devices utilise video-camera technology to visualise airway structures on a monitor and facilitate endotracheal intubation., They offer an improved (and shared) indirect view of the glottis on a remote or built-in video screen. The camera located at the distal end of VLS blade acts as an extension of the eye of the operator, obviating the need to align oral, laryngeal and pharyngeal axes to obtain glottic view., Since the inception of VLSs, there has been a dramatic surge in their use. VLSs are considered one of the most significant advances in airway management in the last two decades.
The latest guidelines from the All India Difficult Airway Association laid emphasis on its role as the first-line airway management tool to decrease the incidence of difficult airway. There has been a surge in the respiratory viruses emerging each year including H1N1, middle east respiratory syndrome and now COVID-19. To minimise the spread of disease during such scenarios, especially during aerosol-generating procedures such as endotracheal intubation, the VLS plays a key role in providing indirect visualisation of the glottis. Worldwide data suggest that 80% of intubations of these patients have been performed using VLSs.
An ideal videolaryngoscope in the current circumstance includes one with a high success rate of tracheal intubation even in patients with a difficult airway and that too in a short intubation time. A device that is disposable or one that can be appropriately disinfected after use offers an added advantage. VLSs are currently available in different designs and configurations [Figure 1].
|Figure 1: Types of videolaryngoscope blades (A) Macintosh blade of CMAC; (B) Hyperangulated blade of CMAC; (C) Non-channelled blade of King Vision videolaryngoscope; (D) Channelled blade of King Vision videolaryngoscope|
Click here to view
VLSs can be broadly divided into:
- Macintosh-shaped VLS, e.g., C-MAC
- Angulated VLS, e.g., GlideScope, CMAC-D Blade
- Channelled VLS, e.g., Ambu King Vision VLS, Airtraq VLS
The majority of VLS cited above fulfil the required preconditions. Despite the advantages offered by these devices, there are certain problems that one often faces while using these otherwise user-friendly devices, more so when the operator has donned personal protective equipment. These problems vary with the type of VLS, depending upon their design and configuration, and could be broadly categorised into equipment-dependent, patient-dependent and operator-dependent factors. Analysis of the common problems faced while using these devices can help in troubleshooting these issues and increasing the success rate.
| Equipment Dependent|| |
Problem with insertion of device into oral cavity (Encountered with King Vision and CMAC-D Blade).
King Vision has a relatively long handle with a fixed mounted camera screen on the proximal end of the handle. Like any other VLS, the blade is inserted along the midline. During insertion of the blade, the handle and the fixed screen impinge on the chest, leaving no space to manoeuvre the blade into the oral cavity.
The CMAC-D Blade has an exaggerated angulation of 40° and a bulky handle. This relatively bulky handle abuts on the patient's chest preventing proper insertion of the blade.
In case of difficulty in insertion, the blade can be inserted from the side of the mouth (like in conventional direct laryngoscopy) and then shifted to the midline for visualisation of the glottic aperture.
Other manoeuvres that could be used include:
- Further extension of atlanto-occipital joint during blade insertion, thereby creating more space for the handle to go cephalad and allow insertion of the blade
- Rotating the handle of the blade 90° to the right before insertion into the oral cavity. Once the blade is inside, the handle is rotated back 90° to the left
- Insert the device rotated 180° into the mouth and then sweep it around the tongue while being advanced further in.
Problem in visualisation or viewing
Commonly encountered with Airtraq, King Vision.
This problem is generally encountered while using the VLS with channelled blades. These devices require the tip of the blade to rest close to the glottic aperture to facilitate tracheal intubation. In an attempt to achieve this, the blade is often inserted too deep.
In case of difficulty in viewing with channelled blades, withdraw the blade slowly till the “best glottic view” is obtained.
Difficulty in inserting the endotracheal tube (laryngoscopy paradox): Encountered with almost all VLS, especially angulated VLS and channelled VLS.
Difficulty with angulated blades
Although the whole glottis is fully visible on the monitor screen, the tip of the endotracheal tube (ETT) repeatedly strikes the area posterior to the glottis.
This most commonly encountered problem is due to the basic difference between direct and indirect laryngoscopy. In direct laryngoscopy, the oropharyngeal curve and the pharyngo-glotto-tracheal curve need to be aligned to permit a direct glottic view before attempting endotracheal intubation. On the other hand, during indirect laryngoscopy with VLSs, these curves need not necessarily be aligned. Better visualisation of the laryngeal inlet does not necessarily translate to easier intubation as the two are not aligned at the time of an ideal glottic view, more so with the angulated blades.
The use of a stylet is mandatory, especially with angulated blades. The stylet should be shaped according to the curvature of the blade.,
The blade of the VLS has to be partially withdrawn resulting in widening of the field of vision and decrease in the percentage of glottic opening (POGO) score. A suboptimal view paradoxically facilitates intubation by changing the angle which the plane of laryngeal inlet makes with the tip of the ETT.
Inflation of the cuff of the ETT angulates its tip slightly anteriorly and at times can help overcome this problem.
Holding the tube closer to the machine end allows greater manoeuvreability and more precise movement at the tip of the tube with even minor movements at the machine end. Subtle movements such as rotating the tube, or moving anteriorly or posteriorly, are amplified in the pharynx, improving the fine control and easy passage of the ETT past the vocal cords.
Difficulty with channelled blades
Reason: The tip of the blade is too close to the glottic aperture. Being used to direct laryngoscopy, we tend to move very close to the glottic inlet with the aim of getting a good view of the glottis. This leaves us with very little space to manoeuvre the tube through the glottis.
Solution: Withdraw the blade of the VLS a little away from its location under vision and advance the tube again. The ideal view during videolaryngoscopy should have the epiglottis at the top, arytenoids at the bottom right, the aryepiglottic folds on the sides and the laryngeal aperture in the centre. Very often, rather than aiming to achieve a Cormack–Lehane (CL) Grade I view or a POGO score of 100%, the lifting force can be slightly reduced to obtain a CL IIa view or a POGO score of <100% which can help to negotiate the tube better. This simple trick has been shown to improve the success rate with intubation.
Impingement of the ETT onto the right aryepiglottic fold: Encountered in channelled VLS such as Airtraq and King Vision.
Reason: This generally occurs due to the rightward positioning of the channel of the VLS. The other reason is that the VLS is advanced “too far in."
Withdraw the VLS blade under vision to get a wider view as stated earlier and reintroduce the ETT.
A counterclockwise rotation of ETT by 90° or 180° can change the trajectory of the ETT towards the left side and can disengage the ETT.,
If still not successful, the entire VLS assembly can be rotated towards the left, thereby directing the tube towards the left side.
2-D view leads to loss of depth perception
Encountered with almost all VLSs.
Loss of depth perception. This can lead to injury to the upper airway due to a potential blind spot of the oropharynx, especially when the operator focuses primarily on the monitor of the VLS.
To avoid such injury, a 4-step approach is followed while using a VLS.
- Look into the oral cavity while inserting the VLS blade until the blade has crossed the maximum convexity of the tongue
- Look at the monitor screen once the tip of the blade has passed the maximum convexity of tongue
- Look into the oral cavity once again while inserting the endotracheal tube into the oral cavity
- Look at the monitor screen once the endotracheal tube has passed beyond the tonsillar pillars until the tube is seen entering the trachea.
| Operator Dependent|| |
Resistance to insertion of ETT beyond vocal cords: Hinging on tracheal rings; encountered with angulated blades.
The hyperangulation of the VLS blade and stylet changes the shape of the ETT distally in such a way that the ETT tip is almost parallel to the plane of laryngeal inlet. This results in difficulty in negotiating the ETT through the glottic aperture.
Use cricoid pressure.,
Loading of endotracheal tube on malleable stylet in forward [Figure 2]a and [Figure 2]b or reverse camber position with a 60° or 90° angulation [Figure 3]a and [Figure 3]b allows an easy passage into larynx. Reverse camber loading refers to placing the angled stylet (90° or 180°) opposite to the natural curvature of the endotracheal tube.,
|Figure 2: (a) Forward camber loading of ETT with 60° angle above cuff; (b) Forward camber loading of ETT with 90° angle above cuff|
Click here to view
|Figure 3: (a) Reverse camber loading of ETT with 60° angle above cuff; (b) Reverse camber loading of ETT with 90° angle above cuff|
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Withdraw the stylet 3–4 cm to straighten the distal angle of the ETT and then push the ETT forward. On crossing the glottic aperture, withdraw the stylet and push the unstyleted tube further down.
Retract the ETT and introduce a gum elastic bougie into the ETT. Now pass the gum elastic bougie into the trachea and railroad the ETT over it.,
Slight flexion of the head and neck results in the ETT making an acute angle with the plane of laryngeal inlet thus facilitating glottic entry.
| Patient Dependent|| |
Decreased mouth opening
Encountered with any VLS.
Following insertion of the VLS, very little space is left to insert the ETT within the oral cavity. In certain cases, there can be difficulty in inserting the tube by the midline approach.
The conventional practice of inserting the VLS along the midline results in the VLS occupying the major portion of the oral cavity, leaving little space for ETT insertion.
The blade of the VLS can be inserted from the left retromolar space, while the ETT can easily be inserted from the right retromolar space.
In conclusion, VLSs now constitute key devices in the armamentarium for airway management. A thorough understanding of the equipment including its strengths and weaknesses, along with the knowledge of the simple troubleshooting tips, can remarkably improve the success rate with these devices.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]