Journal of Anaesthesiology Clinical Pharmacology

REVIEW ARTICLE
Year
: 2021  |  Volume : 37  |  Issue : 1  |  Page : 14--27

Evolution of videolaryngoscopy in pediatric population


Anju Gupta1, Ridhima Sharma2, Nishkarsh Gupta3,  
1 Department of Anaesthesia, Pain Medicine and Criticial Care, All India Institute of Medical Sciences, Delhi, India
2 Department of Anesthesiology, SPHPGTI, Noida, Uttar Pradesh, India
3 Department of Onco-Anesthesiology and Palliative Care, DRBRAIRCH, AIIMS, Delhi, India

Correspondence Address:
Dr. Anju Gupta
Room No. 6, Porta Cabin, Teaching Block, All India Institute of Medical Sciences, Ansari Road, New Delhi - 110029
India

Abstract

Direct laryngoscopy has remained the sole method for securing airway ever since the inception of endotracheal intubation. The recent introduction of video-laryngoscopes has brought a paradigm shift in the pratice of airway management. It is claimed that they improve the glottic view and first pass success rates in adult population. The airway management in children is more challenging than adults. The role of videolaryngoscopy for routine intubation in children is not clearly proven. This review attempts to discuss various videolaryngosocpes available for use in pediatric patients.



How to cite this article:
Gupta A, Sharma R, Gupta N. Evolution of videolaryngoscopy in pediatric population.J Anaesthesiol Clin Pharmacol 2021;37:14-27


How to cite this URL:
Gupta A, Sharma R, Gupta N. Evolution of videolaryngoscopy in pediatric population. J Anaesthesiol Clin Pharmacol [serial online] 2021 [cited 2021 Jun 25 ];37:14-27
Available from: https://www.joacp.org/text.asp?2021/37/1/14/313427


Full Text

 Introduction



Airway management is a vital skill for the anaesthesiologist as it is an intergral part of general anaesthesia (GA). Ever since the inception of endotracheal intubation, direct laryngoscopy (DL) has been an indispensable part of routine and difficult airway (DA) management. However, it was realized over the course of time that airway related adverse perioperative events are an important contributor to the morbidity and mortality.[1] Introduction of video-laryngoscope (VL) is an important technological advancement that has facilitated endotracheal intubation (ETI) and has the potential of decreasing its adverse consequences.[2]

Nowadays, VL is emerging as a tool of choice for ETI as they provide better view and higher success rate especially in difficult intubation situations and they can be used as a tool for teaching. In addition to this, a faster learning curve as compared to DL obviates the need of an experienced laryngoscopist.[3],[4]

VL involves indirect visualization of laryngeal structures during intubation using optical and video technology that helps the anaesthetist see around corners in the upper airway and obtain a clear glottic view. VL's eliminate the need for a direct line of sight to visualize the airway, reduce the force required to visualize the airwary structures, causes less local tissue distraction and reduce the stress response.[2],[5]

The first generation of VLs were developed based on the technology used in rigid fibreoptic laryngoscopes like Upsher scope (UL), the Bullard (BL) and the Wuscope.[6] The need of long training periods and the high incidence of complications made them obscure.[7] In 2001, a new type of VL arrived in the shape of the Glidescope (Verathon Company, USA). Subsequently, the following VLs with adequate complement of pediatric sizes were introduced: The Storz videolaryngoscopy (SVL) original version direct coupled interface (DCI), C-MAC, Glidescope, TruView-PCD, Airtraq, McGrath series 5, KingVision.

There is ample evidence in favor of VL over direct laryngoscopy (DL) for intubation in adult patients with normal and DA.[2],[3],[8] Difficult airway society guidelines[9] have also recommended VL for initial intubation and management option.

In contrast to adults, airway management in children—particularly in neonates and infants—can be more challenging. The overall incidence of difficult laryngoscopy (Cormack and Lehane Class ≥ III) is significantly higher in infants (4.7% vs. 0.7%) as compared to older children.[10] This may be due to various anatomic factors such as the more anterior and cephalad larynx, large overhanging epiglottis, large tongue, shorter mandible and prominent occiput which complicate airway management particularly in infants. Moreover, apnoea time is greatly reduced in children, as compared to adults, and awake intubation may not be feasible.[1],[10]

VLs which have been introduced in paediatric practice are generally the scaled down version of the adult devices. It is a well recognized fact that airway related complications in children can be mitigated if the number of intubations attempts are restricted.[11] VLs are a promising option in this regard as they have been shown to improve glottic view and first attempt success rates especially in difficult airway scenarios.[12],[13] Though VLs have shown encouraging results in various randomized controlled trials (RCTs) conducted in paediatric patients, their exact role at present remains unclear in this population. A meta-analysis[12] comparing the clinical efficacy of paediatric VL with DL demonstrated that VLs improved glottis view. However, they had cautioned that further studies are required to explicitly recommend its routine clinical use.

A Cochrane metanalysis[13] of VL assisted intubation in neonates concluded that there was insufficient evidence to recommend or refute the use of VL for endotracheal intubation in neonates. Well-designed, adequately powered trials are necessary to address efficacy and safety of VL for endotracheal intubation in neonates. The current review is intended to highlight the evolution of different types of paediatric specific VLs, their advantages, limitations and comparison of various devices in pediatric population.

 Search Strategies



The measures adopted included extensive scrutiny of literature evidence from internet resources, journals and textbooks in the PubMed database using the key words “video laryngoscopy”, “video laryngoscope”, “GlideScope®”, “Airtraq”, “C-MAC”, “TruView”, “KingVision”, “children”, “Paediatric”, “infants”, “indirect-laryngoscopes”, “rigid-fibreoptic scope”, “bonfils” and various internet-based databases carrying the detailed information related to paediatricsVLs. The strategies included exploration of full text articles and abstracts from various search engines such as PubMed, Medscap, Google Scholar Medline Scopus, EMBASE, Science Direct, Yahoo and many others.

 Classification



VLs may be categorized either by the method used to produce the image (video, fibreoptic or mirror/prism) or by the means used to deliver the tube. Various classifications have been proposed but most commonly used system is as follows:[14],[15]

Non-channeled: The tube is steered into position by the anaesthetist, usually on a curved stylet [e.g., Glidescope (Verathon Inc.), McGrath (Aircraft Medical), C-MAC (Karl Storz)]. These VL may be based on Macintosh design which provides an additional advantage that both DL and VL features are available, especially for those familiar and experienced with the Macintosh blade. e.g., McGrath Mac, Storz V- Mac and C- Mac VLs.[16] Some of these VLs have a hyperangulated curvature which significantly improves glottis visualization with negligible neck flexion and head extension e.g., Glidescope (GVL), McGrath Series 5 and Storz C-Mac D- blade.[2],[16] However, it is often difficult to intubate and a precurved stylet is often required for intubation.Channeled: The laryngoscope incorporates a channel to deliver the tube [e.g., Airtraq (Airtraq), Bullard (Gyrus Medical)]. They do not require stylet and often have a groove for housing ETT and directs it towards the center of the image viewed.Optical stylet: The tube is preloaded over the stylet [e.g., Bonfils (Karl Storz), Clarus Shikani and Levitan (Timesco)].

 Technique of Videolaryngoscopy



Laryngoscopic technique varies between devices but with the exception of optical stylets, most are introduced along the midline of the mouth, over the tongue. As the device is advanced, the anaesthetist looks at the screen rather than at the tip of the scope until the larynx is visualized. This 4-step 'in-out' technique of videolaryngoscopy was first described for Glidescope VL but is applicable to all VLs:[17]

Insertion of the VL blade into the oral cavity under direct visualization (look 'in')Look at the projected image on the screen for optimal laryngeal viewing (look 'out')Direct visualization of the ETT entering the centre of mouth till it enters the pharynx (look 'in')Look at the projected image for further guiding of the ETT towards glottis for intubation (look 'out').

Bird's eye view

If the the blade is kept too close to the glottis opening, intubation will be difficult. So, the blade should be withdrawn slightly to provide more of a bird's eye view. This will decrease the angle along with facilitating the tube insertion.

 Storz Videolaryngoscopes (SVL)



“Karl Storz endoscopes” have developed direct coupled video intubation system (DCI) that can be connected to a variety of intubating devices. The original version is Berci- Kaplan VL or V- Mac and its next generation are Boedeker Dorges VL or C-MAC. Others are Bonfils intubating endoscopes and flexible intubation fibrescopes.

 Elucidation of the Device



Storz DCI VL integrates the camera with an ergonomic handle which can be attached to a series of blades in paediatric size. The video lens is situated by the light source near the end of the blade and provides an angle view of 80°. The latest version of storz DCI VL is the C-MAC.

 C- MAC (Karl Storz® SE and Co. KG, Tuttlingen, Germany)



The C- MAC is analogous to Macintosh and Miller blades connected to a rectangular handle. It's a modification of the older V-MAC device. The tip of the blade has a 320 × 240 pixel complementary metal oxide semiconductor video chip and fog resistant lens. The video system is mounted on a small mobile cart and supports an 7-8 inch monitor mounted on the patients left side.[18] It may also have a 2.4-inch pocket monitor. Different paediatric blade sizes which are available include Miller 0, 1, Macintosh 2 and C-MAC D-blade size 2 [Figure 1]. The various advantages and disadvantages of C-MAC VL have been summarized in [Table 1].{Figure 1}{Table 1}

 Technique of Insertion



C-Mac blade introduced via midline approach takes lesser time.[19] C–Mac is introduced like a conventional laryngoscope via right side, tongue swept to the left by the blade flange, advanced into the epiglottic vallecula and then raised to obtain laryngeal view. In case of poor laryngeal view, optimization maneuver can be performed (OELM and blade position adjustment).

 Literature Appraisal and Evidence



Various prospective randomized trials [Table 2] showed the Storz VL provided better laryngoscopic views as assessed using percentage of glottic opening (POGO) scores and on Cormack-Lehane scores (CL)[21],[22] as compared to DL in children (infancy through adolescence).{Table 2}

Donoghue et al. compared C-MAC to direct laryngoscopy in mannequins (neonate, infant, and adult) and found improved POGO scores with VL.[23] Fiadjoe et al., performed a study in an infant mannequin with limited neck extension using conventional and C-MAC Miller blades. They found C-MAC Miller blade improved glottis view by at least one CL grade in 78% patients, with no difference in time to intubation and resulted in fewer failed intubations.[24]

The largest published study[25] (descriptive case series) in neonates (weight 530 g-6795 g) found successful intubation with VL in all the 5 patients that could not be intubated using DL. In 6 cases, video assistance helped to prevent repeat attempts probably due to improved anatomic view. The diagnosis of vocal cord paresis could also be made on VL, that could be perhaps missed on the DL.

In infants with normal airway, C-MAC has fared better in terms of faster intubation time and ease of use, when compared to the TruView Infant EV02.[26]

C-MAC VL also had a lower IDS score (intubation difficulty score) when compared to conventional Miller blade due to improved CL grade, reduced laryngeal pressure and decreaesed lifting force.[27] In a Prospective randomized trial on intubation in lateral position in infants (n = 64), CMAC VL decreased the time to intubation 6.1 s (1.7-10.4) and reduced the IDS as compared to conventional Miller blade.[28]

Moussa et al.[29] conducted a study on 34 novice paediatric residents for intubation in infants (32 weeks) with a median weight of 1500 g. They deduced a higher intubation success rate (75%), rapid learning curve (2nd vs 7th intubation) and a need for longer time to intubation with C-MAC (57 vs 47 s) than DL. Soft tissue trauma was observed more with conventional laryngoscopy.

 Bonfils (Karl Storz GmbH, Tuttlingen, Germany)



The use of the Bonfils Retromolar Intubation Fiberscope was first described by the Bonfils in 1983. The retromolar approach was used to intubate the tracheas of children with Pierre Robin syndrome.[30] The adult version is a rigid straight fiberoptic device with a curved tip of 40-degree for targeted intubation, a length of 40 cm and outer diameter (OD) of 5 mm. The necessary overview is ensured by the 110-degree angle of view. There is a central channel through which oxygen can be insufflated and local anaesthetics can be instilled. The eyepiece is mounted at the proximal end of the handle that can be connected to a camera, video monitoring system or can be viewed directly. A portable battery powered light source can be attached to the handle (stylet). For children, 2 other sizes with a 2-mm (for ETT 2.5-3.5 mm ID; shaft length 22 mm) or 3.5 mm OD are available (suitable for ETT 4.0-5.5 mm ID; shaft length 35 mm) [Figure 2]. The various advantages and disadvantages of Bonfils intubation fiberscope (BIF) have been summarized in [Table 3].{Figure 2}{Table 3}

 Technique of Insertion



A chin-lift/tongue-jaw lift is performed by grasping the tongue and mandible and lifting them verticlally upwards away from the posterior pharynx to expose the laryngeal inlet. The scope is introduced alongside the molars from the right side of the mouth and forwarded underneath the epiglottis and the scope is cautiously guided to visualize the tracheal rings and the Bonfils tip is then positioned safely. Thereafter, the ETT is railroaded into the trachea after releasing it from the holder using corkscrew motions.

In the mid-line technique, the scope is advanced to reach the epiglottis and when the ETT passes the vocal cord, ETT is advanced into the trachea. For a beginner, this approach is easy and also instead of chin-lift maneuver, one can do DL that increases the retropharyngeal space for the introduction of the bonfils.[31]

 Literature Appraisal and Current Evidence



Bein et al.[33] reported a first attempt success rate of 72.7% and overall success rate of 89.1% with the paediatric Bonfils device (outer diameter of 2 mm and 3.5 mm) by an experienced operator in children (6 months-4 years) with normal airways. All the 6 failed intubation attempts were because ofcopious secretions badumbrating the view. The authors concluded that Bonfils fiberscope has significant drawbacks when used for intubation of normal pediatric airways due to its high failure rate and prolonged intubation times.

Houstan et al.,[34] conducted a randomised cross over trial in healthy children (2-4 years) to compare bonfils with conventional laryngoscopy. In the Bonfils group, first DL followed by Bonfils aided intubation and vice versa in the conventional group. After 2 attempts, the success rate was 92.3% for the bonfils group and 100% for the DL group, respectively. They concluded that though the Bonfils fiberoscope improved glottic visualization as compared to DL, but there was a higher incidence of failure to intubate. Bonfils has been shown to provide a better image quality, easier to operate, constant view of the tracheal tube passage, and lead to faster times to intubation when compared to Fiberoptic bronchoscope in children with difficult airway.[35]

Vlatten et al. compared Bonfils fiberscope with DL in simulated difficult infant intubation in manikin and found that Bonfils was easier to use and gave better laryngeal views, but did not improve intubation success rates and intubation times.[36]

There are many case reports advocating the use of the Bonfils in children with difficult airway, especially in children with decreased intraoral space, where Bonfils has a distinct advantage over LMA, Glidescope VL, Airtraq and DL.[37],[38] The literature in relation to use of Bonfils fiberscope has been summarized in [Table 4].{Table 4}

 Glidescope Video Laryngoscope (GVL)



GVL is the first VL that was introduced by John Pacey (Canadian Surgeon) in 2001. It is non-channelled VL that was one of the first introduced in adult and pediatric size, and subsequently all spectrums of pediatric versions accessible since 2005. The non-channelled GVL is essentially a camera mounted on a specially shaped laryngoscope handle with an acutely angled blade (It is available in sizes 3 and 4 only and shape is similar to MAC blades). The adult GVL have height of 16 mm (max) at the mouth and its blade angles to 60 degrees with inbuilt camera at the inflection point. It provides real-time continuous image that is illuminated by a light-emitting diode and can be seen on a separate color monitor.

The GlideScope Cobalt comes in an infant size with a smaller height (10 mm) laryngoscope blade, which permits its use in neonates. There are a variety of other GlideScope products available, including fully portable and reusable designs, but all are variations on the above-described device [Figure 3].{Figure 3}

The primitive reusable GVL2, evinced to be vain in small children[39] and was superseded by the cognate Glidescope Cobalt. Other models with pediatric sizes include the AVL (advanced videolaryngocope), the Titanium and the Ranger. Nowadays, AVL 2 reusable, modified version of GVL 2 is also available though they are not usable in neonates and small children. GVL Ranger is portable device with an antireflective screen for use in daylight (apt for use in the field) and can store upto 60-minute video recording.

The AVL-S and Cobalt have reusable baton covered by the disposable (same) hard sleeve made up of plastic known as “Stat”. The manufactures recommend a weight range of 0.5-28 kg with 4 sizes stats available for the pediatric baton. Its various advantages and disadvantages have been summarized in [Table 5].{Table 5}

 Technique of Insertion



The blade is inserted in the midline, and the ETT is bent to resemble the shape of the blade[48] using a dedicated stylet. The GVL blade is slowly moved by rotating the device along the natural curvature of the base of the tongue into the vallecula. The four step in-out technique as described previously is followed.[17]

 Literature Appraisal and Evidence



Various studies with pediatric GVL have reported significantly better view of the glottis.[43],[44],[45] Various studies and case reports have demonstrated improved conditions for intubation with the GVL in comparison to DL in normal and predicted difficult airway in children.[44],[46],[47]

In a prospective randomized trial comparing intubation time with GS cobalt VL and DL with a Miller blade in neonates and infant (n = 60) reported similar intubation time and success rate. It was observed that the GS cobalt provided faster views but prolonged the ETT passage time.[48]

Hyung-jung Kim et al., compared the GVL and DL laryngoscopy for nasotracheal intubation in 80 childrenless than 10 years posted for elective dental or facial surgery and concluded that in GVL provided similar time to intubation in experienced hands.[49]

A large study[25] performed in the neonatal population (530 g to 6795 g) showed that GVL improved glottic view. It helped to diagnose vocal cord paresis in one patient that may have been missed on conventional laryngoscopy and also prevented repeat attempts by trainees in six cases. In 5 patients with failed DL previously, the author observed that VL resulted in successful intubation.

Sylvia et al. compared the GVL to DL and found a slightly longer time to intubation (median of 36 seconds vs 23 seconds) with no difference in success rate.[50] In a study of pediatric interns, similar rates of success was seen between GVL and DL, with longer time to intubation when using the VL. In spite of these results, the Glidescope was the elected device among the majority of the participants.[51]

Kim[45] et al. conducted the study in 203 children with and without manipulation, i.e., backward, upward and rightward pressure (BURP), comparing the GVL with a DL using Macintosh blade and concluded better laryngoscopic structure, but a longer time to intubation, with GVL (36.0 ± 17.9 vs 23.8 ± 13.9 s).

A recent pediatric difficult intubation registry assessed the efficacy of GVL and DL for intubation in 1295 children with anticipated difficult intubation on intial attempt of DL. GVL had higher success rate than DL without increasing the complications.[52] Though GVL was better than DL but overall success in children less than 10 kg was lower than adults.

 TruView Videolaryngoscope



The TruViewPicture Capture Device (PCD) (Truphatek International Limited, Netanya, Israel) is a successor of the TruView Infant EV02. In 2006, the TruphatekTruView EVO2 system was introduced for adult[53] and later on, in 2009, it began to be used in pediatrics.[54] It has an integrated optical lens laryngoscope that can be connected to a videomonitor via a eyepiece on the handle [Figure 4]. There are four paediatric blades (sizes 0, 1, 2 and 3) available for intubation in neonates from more than 800 g to obese children. The blade of the device has a 46 degree anterior refracted angle that allows a wide and magnified image of the larynx without having to align the three axes (oral, pharyngeal, and tracheal axes).{Figure 4}

A distinctive feature of the device is an integrated oxygen jet to provide apneic oxygenation (flow 2-5 l/min-1) and anti-fogging of the camera. A special stylet (the OptiShapeTM) is also available with the TruView for better angulation and providing rigidity to the endotracheal tube.

 Literature Appraisal and Evidence



A manikin study was conducted with normal and simulated difficult airways in novice operators, and concluded improved glottis visualization with the TruView VL. A long time to intubation was observed in difficult airway scenarios in the TruView than the conventional Macintosh blade and more dental clicks considered as indicative of dental trauma,[55]along with manipulation difficulty due to its bulky nature was noticed in the TruView operators.

In a study by Riveros et al., of pediatric cohort ranging from neonates to 10 years of age, the TruView was compared to Glidescope and DL with Macintosh blade.[39] They recorded longer mean intubation times (44 seconds vs 23 seconds) in the Truview group along with similar glottic views as compared to DL. The inbuilt safety feature of oxygen insufflation did not avert fall of oxygen saturation below 90% due to longer intubation times.

A comparative study of the Macintosh laryngoscope, C-MAC VL and the Tru View Infant EV02 PCD in infants (<10 kg, up to 22 months) reported longest median time for intubation with Truview PCD (52 s) than C-MAC (28 seconds) and Macintosh (26 seconds) laryngoscopes though the glottic view was better in the TruView group. Also, the user satisfaction score was lowest with the Truview EVO2 due to non-familiarity with the instrument.[26] Fogging was reported as a hinderance with TruView VL. In parallel to the previous study, the use of TruView EV02 resulted in a fall in SpO2 related to the longer times to intubate. Similar findings of increased intubation times leading to desaturation and fogging as a cause of intubation failure were reported in another recent study.[27]

Similar findings of improved laryngeal view along with increased intubation times as compared to conventional laryngoscopy were reported in a study on 60 neonates and infants (1-10 kg) and another study on 50 children aged 2-8 years.[54],[56]

Although there exists a paucity of literature supporting the utilization of the TruView in the paediatric difficult airway cohort, but there are a few case reports, showing successful intubation in cases where previous intubation had failed.[57],[58]

In a randomized trial[59] comparing the Truview, C-MAC, and Macintosh laryngoscope in 150 paediatric patients airway aged 1-6 years, authors concluded that percentage of the glottic view (POGO score) was better with TruView than C-MAC and Macintosh bladebut it still required the longest time to intubate. They highlighted that Truview PCD, gives a better view than conventional Macintosh laryngoscope, on the other hand C-MAC provides high resolution views and is a good teaching tool.

 Airtraq Videolaryngoscope



The Airtraq (Prodol Meditec, SA; Vizcaya, Spain) is a channeled disposable optical laryngoscope, available in different sizes with the smallest size 0 infant scope. It has an eye-piece on the handle that can be connected to a 2.8 inch camera that uses Wi-Fi for projecting the image or 7-cm video monitor (external) [Figure 5].{Figure 5}

It has 2 channels, the guide channel on the side of the device through which ETT is advanced, and the other is the optical channel containing the lens for indirect viewing. The device has a unique integrated warming system at the light source and the camera that should be turned on for at least one minute for the anti-fogging system. Recently, 50 times reusable version known as Airtraq Avant with a disposable eyepiece and an optical baton is also now available.

 Technique of Insertion



The device is inserted into the oral cavity in the midline, the flange on the tip of the blade is either passed into the vallecula or lifts the epiglottis. Before intubation, the ETT should be properly lubricated and after visualization of the vocal cords in the center of the field (back-and-up maneuver), it is advanced through the guiding channel. After advancing the tube into the vocal cord, it is kept stationary and the device is dragged laterally to the left to disengage the ETT from the channel and removing the device. In case of difficult scenario, Airtraq can be introduced in the oral cavity like a Guedal airway (upside down) before moving it through 180 degree.[60] The instrument is bulky compared to conventional DL and may pose difficulty in patients with limited mouth opening or small oral cavities.[61]

 Troubleshooting



Passing the ETT through the vocal cords may be difficult.[61],[62] Gum elastic bougie, fibreoptic bronchoscopes and stylets can be used in case of troubleshooting[63]The Triple maneuver (downward, backwards and upwards) may be done in case of poor laryngeal view. Also, inadequate laryngeal visualization may be due to the device being inserted too far and is ameliorated by gentle withdrawal.[64]

 Literature Appraisal and Evidence



A meta-analysis comparing different videolaryngoscopes, including Airtraq, concluded that the quality of the evidence was low.[65] VLs improved visualization of the glottis but prolonged the intubation time in contrast to direct laryngoscopy.

The skilled operators have experienced lack of superiority of the device over conventional laryngoscopy in routine patients,[66] however, in cases with a difficult airway, the device has demonstrated less time to intubation and improved success rate.[67]

Studies have suggested the utilization of the device in patients with unstable or restricted movement of the cervical spines due to less cervical motion as compared to Macintosh DL.[68] It has been also used for awake intubations.[69]

In infants and children under 5 years, Airtraq exhibited better POGO scores but a longer duration of intubation in comparison to conventional laryngoscopy.[70],[71]

Airtraq has been used in various difficult airways in pediatrics[21] and also the device has a shorter learning curve for novices, compared to DL.[72]

In 2012, a study compared Airtraq with the airway scope (Pentax) for intubation in an infant manikin simulating cardiopulmonary resuscitation (CPR), where the subject was at rest and found time to intubation and visualization of glottis was longer in Airtraq during CPR and at rest.[73]

Various studies have reported less time to intubation, improved visualization and less number of esophageal intubation with the Airtraqin children.[74],[75] However, the evidence regarding the utilization of the Airtraq is mostly on normal airway in pediatric cohort.

 McGrath Videolaryngoscope



The McGrath MAC VL (Aircraft M e d i c a l, E d i n b u r g, U n i t e d Kingdom) has a Macintosh style blade which was introduced to clinical practice in 2010. It has a fixed length metal alloy camera stick used with a plastic disposable blade that slides over it. The bladesizes 2,3 and 4 have a maximum blade height of 11.9 mm, thereby minimizing the required mouth opening for its use. The pediatric version of the McGrath series 5 include a Mac 2 sized disposable, portable, single use, non channeled blade for small children and more recently, size-1 blade to facilitate intubation in neonates and infants [Figure 6]. The blade has a unique feature of “vertically aligned optics” that reduces the 'Blind spot' as described by the manufacturers. It produces a real time color 2.5 inch screen mounted on handle for video-display and has a light source on the tip of the blade. There exist no anti-fogging system, still the McGrath has a hydrophilic optical surface coating to reduce fogging on the light source.{Figure 6}

The greatest advantage of this new small videolaryngoscope blade is the magnification of the view of the laryngeal inlet. This provides a further advantage in the demonstration and training of neonatal intubation. The device emulates the traditional Macintosh laryngoscope in both design and the application of an appropriately sized blade to a standard handle. The device can be used similar to Macintosh blade and required less force for intubation on normal and difficult airway.

 Technique of Insertion



McGrath Mac can be used akin to conventional laryngoscopy, in that the device can be introduced in the oral cavity under direct vision. The blade tip is placed in the vallecula with the image lying centrally in the upper third of the display.

 Troubleshooting



There could be difficulty in directing the ETT through the vocal cords and may require external manipulation or bougie.

 Literature Appraisal and Evidence



The McGrath is relatively a recent device, there exist paucity of well- studied literature, especially in difficult airways and evidence of efficacy have been mainly limited to successful case reports.[76],[77],[78] The McGrath was used successfully in a 9 yr old child with extensive burn with scarring in face and neck where fibreoptic laryngoscopy had failed and the device provided a Cormack and Lehane grade 1 view.[77] The device was used successfully in a previous failed direct laryngoscopy in a 13 yr old child with Treacher Collins syndrome and here also it improved the view from grade 4 to grade 1 compared with DL.[78]

In a study of 90 paediatric cases aged 4-10 years, the ease of insertion, glottis view was compared with McGrath, TruView EVO2 and Macintosh laryngoscope.[79] The POGO score in the Macintosh laryngoscope group was lower than the other two groups. The requirement of external manipulation was increased in Truview EVO2 group and the intubation difficulty score (IDS) was also significantly more in Truview EVO2. The time of intubation was found to be statistically significantly shorter in the McGrath videolaryngoscopy group while the number of attempts for intubation were similar in all 3 groups.

In 2008, a study was presented at the ASA annual meeting concluding good conditions for intubation in children with a mean age of 63 months with normal airways.[80] Use of the infant blade of McGrath MAC (size 1) has only been documented in a small series of six cases of neonatal intubation by Ross et al., who noted an improved glottic view withthis VL over that obtained under direct laryngoscopy.[81]

Manikin studies have demonstrated encouraging results for McGrath VL. McGrath was considered to be faster and allowed a higher rate of first attempt intubation success rate in paediatric manikin study even during ongoing chest compression.[82]

A paediatric manikin study, comparing McGrath MAC with conventional laryngoscopy in simulated immobilized cervical spine patients, McGrath was recommended as the first intubation option for endotracheal intubation in difficult paediatric emergencies.[83]

 KingVision® a Blade Videolaryngoscope



KingVisionTM is a curved single-component, wireless, lightweight, portable battery operated reusable device with disposable high angulation non-channeled or channeled blade (Ambu® A/S, Bad Nauheim, Germany). Single-use blades eliminate risk of cross contamination. King Vision laryngoscope (KVL) is ergonomically designed to provide clear image viewing in 160° panoramic field with minimal lifting of soft tissue and impact on teeth. It has 2.4 inch organic light emitting diode display with advanced imaging technology that includes a video-camera (complementary metal- oxide semiconductor).

Recently its paediatric version King Vision a Blade has been introduced for clinical use in children. The device has three pediatric blades: size 1, 2 non-channeled and a size 2 channeled version.

 Technique of Insertion



It is introduced in the oral cavity like a Macintosh blade and its tip is positioned in the vallecula. It produces an indirect glottis view without the requirement of oral- pharyngeal tracheal axis alignment.

 Troubleshooting



The tip of the channeled blade can go too deep inside the airway resulting in the uploading of the epiglottis leading to difficulty in directing the tube towards the glottis causing longer time to intubation.

 Literature Appraisal and Evidence



KVL is a relatively new device and has paucity of literature evidence in its favor or against it. Adult studies have yielded variable results with success rates ranging from 51% to 100% on intubation with KVL.[84] At present, literature is deficient on clinical use of KVL in children. Only one clinical trial has been published on children <2 years of age and the authors found comparable time for intubation with KVL as compared to conventional laryngoscopy using Miller blade.[85]

In a bi-centric randomized comparison of KVL and the C-MAC paediatric D-blade to conventional laryngoscopy for intubation in an infant high-fidelity simulator in normal and difficult airway scenarios,[86] VLs were associated with shorter times to ventilation in both situations. In the DA scenario, both the VLs (KVL > CMAC) attained higher first-pass intubation success rates. These advantages of VL can potentially avoid desaturations and decrease adverse events in pediatric airway management.

A manikin study compared channeled Kingvision VL with non channeled and Macintosh blade and concluded better rate of successful intubation (87%) with the channeled compared to non channeled KVL (47%).[87]

 Emerging Roles of VL: Teaching/Training, Safety and Quality Assurance



Improvement of knowledge, technical skills, and cognitive skills are necessary for the education and training of the difficult airway management. Regular seminars, hands-on training session for technical skills, simulation/scenario-based training sessionsare important to attain and mainten the requisite airway management skills. VL play an important role in the teaching and training of endotracheal intubation. VL is associated with a faster learning curve thereby resulting in a higher success rate for intubations and quality assurance by novice physicians.[3],[27] VL with macintosh design can assist with the learning of both conventional and indirect laryngoscopy, and this may decrease airway morbidity by preventing additional intubation attempts in case of difficulty. The VLs not only have better effectiveness but the possibility of theentire operating room personnel watching the intubation procedurewhich in turn, could enhance teaching, improve team dynamics, hasten the response in crisis and mayimprove overall patient safety. Due to the better glottic view imparted by VLs, unanticipated difficult intubations may be less frequent if these are used as the first-line approach. Videolaryngoscopy gives us the option of continuous recording of the intubation process particularly valuable in video recording of critical events and procedure.[88] This may help in clinical documentation, quality improvement, research and teaching. They also create an opportunity for remote supervision by a more experienced airway manager, which may be beneficial in rural hospitals and during prehospital emergency airway management.[89] It provides continuous recording particularly valuable in a video recording of critical events and procedure.[88] Although, there exists no large data, but primitive evidence in a paediatric cohort suggested better outcome in patients with normal and difficult airway.[90]

 Pitfalls and Hinderances to Routine Use of VL



They are much more expensive compared to DL. If VLs become the first line devices for endotracheal intubation, all sites where airway management is anticipated would require stationing of these devices raising overall costs multifold.If VLs become the routine airway management device, existing difficult airway algorithms would need to be modified to begin with videolaryngoscopy failure and the choice of next device would be more complex.[3]VL requires additional training and attainment of learning curveto reach proficiency with each type of device.The number and types of VLs in market are growing exponentially and not all devices are equally effective in all scenarios. Relative efficacy of these devices has not been conclusively proven and this may increase confusion in their selection for management of a particular challenging case.It may difficult to insert ETT especially with an angulated blade VL.VL is difficult to use in patients with limited mouth opening.While inserting a styletted tube, airway soft tissue injury may occur due to operator's focus on the video monitor ('blind spot' related to VL).Use of VLs for routine airway management can possibly reduce the incidence of unanticipated difficult intubation. This might negatively impact the impetus to learn and teach use of alternate airway devices and indirectly affect patient safety in long run.[3]

 Conclusion



The emergence of videolaryngoscope has expanded the airway armamentarium and they are being considered as an important tool in paediatric airway management. They have demonstrated encouraging results in improving the glottic views and intubation success in difficult airway scenarios. However, current evidence on efficacy of VL in the paediatric population is not voluminous and further well-designed large clinical trials are needed to conclusively prove their role in the routine clinical practice of this particularly vulnerable cohort.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Morray JP, Geiduschek JM, Caplan RA, Posner KL, Gild WM, Cheney FW. A comparison of pediatric and adult anesthesia closed malpractice claims. Anesthesiology 1993;78:461-7.
2Niforopoulou P, Pantazopoulos I, Demestiha T, Koudouna E, Xanthos T. Video-laryngoscopes in the adult airway management: A topical review of the literature. Acta Anaesthesiol Scand 2010;54:1050-61.
3Paolini JB, Donati F, Drolet P. Review Article: Video-laryngoscopy: Another tool for difficult intubation or a new paradigm in airway management? Can J Anaesth 2013;60:184-91.
4Nouruzi-Sedeh P, Schumann M, Groeben H. Laryngoscopy via Macintosh blade versus GlideScope: Success rate and time for endotracheal intubation in untrained medical personnel. Anesthesiology 2009;110:32-7.
5Bucx MJ, Scheck PA, Van Geel RT, Den Ouden AH, Niesing R. Measurement of forces during laryngoscopy. Anaesthesia 1992;47:348-51.
6Cooper R, Law J, Hung O, Murphy MF, Law JA. Rigid and Semi-Rigid Fiberoptic and Video- Laryngoscopy and Intubation, Management of the Difficult and Failed Airway. NewYork: McGraw Hill Medical; 2007.
7Drummond M, Magalhaes A, Hespanhol V, Marques A. Rigid bronchoscopy: Complications in a university hospital. J BroncholInterven Pulmonol 2003;10:6.
8Su YC, Chen CC, Lee YK, Lee JY, Lin KJ. Comparison of videolaryngoscopes with direct laryngoscopy for tracheal intubation: A meta-analysis of randomised trials. Eur J Anaesthesiol 2011;28:788-95.
9Frerk C, Mitchell VS, McNarry AF, Mendonca C, Bhagrath R, Patel A, et al. Difficult airway society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015;115:827-48.
10Fiadjoe JE, Nishisaki A, Jagannathan N, Hunyady AI, Greenberg RS, Reynolds PI, et al. Airway management complications in children with difficult tracheal intubation from the pediatric difficult intubation (PeDI) registry: A prospective cohort analysis. Lancet Respir Med 2016;4:37-48.
11Graciano AL, Tamburro R, Thompson AE, Fiadjoe J, Nadkarni VM, Nishisaki A. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: A report from National emergency airway registry for children. Intensive Care Med 2014;40:1659-69.
12Sun Y, Lu Y, Huang Y, Jiang H. Pediatric video laryngoscope versus direct laryngoscope: A meta-analysis of randomised controlled trials. Paediatr Anaesth 2014;24:1056-65.
13Lingappan K, Arnold J L, Shaw TL, Fernandes CJ, Pammi M. Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in neonates. Cochrane Database Syst Rev 2015;6:CD009975. doi: 10.1002/14651858.CD009975.pub3.
14Hurford W. The video revolution: A new view of laryngoscopy. Respir Care 2010;55:1036-45.
15Thong SY, Lim Y. Video and optic laryngoscopy assisted tracheal intubation--the new era. Anaesth Intensive Care 2009;37:219-33.
16Asai T. Videolaryngoscopes: Do they truly have roles in difficult airways? Anesthesiology 2012;116:515-7.
17Walls RM. Essential techniques for using a videolaryngoscope. Anesthesiol News 2009;35:30-11.
18Aziz M, Brambrink A. The Storz C-MAC video laryngoscope: Description of a new device, case report, and brief case series. J Clin Anesth 2011;23:149-52.
19Green-Hopkins I, Nagler J. Utilization of Video Laryngoscopy Recordings to Evaluate Pediatric Endotracheal Intubation Success Rates and Complications. Vancouver, BC: Pediatric Academic Societies; 2014.
20Howard-Quijano KJ, Huang YM, Matevosian R, Kaplan MB, Steadman RH. Video-assisted instruction improves the success rate for tracheal intubation by novices. Br J Anaesth 2008;101:568-72.
21Vlatten A, Aucoin S, Litz S, Macmanus B, Soder C. A comparison of the storz video laryngoscope and standard direct laryngoscopy for intubation in the pediatric airway--A randomized clinical trial. Paediatr Anaesth 2009;19:1102-7.
22Macnair D, Baraclough D, Wilson G, Bloch M, Engelhardt T. Pediatric airway management: Comparing the Berci-Kaplan video laryngoscope with direct laryngoscopy. Paediatr Anaesth 2009;19:577-80.
23Donoghue AJ, Ades AM, Nishisaki A, Deutsch ES. Videolaryngoscopy versus direct laryngoscopy in simulated pediatric intubation. Ann Emerg Med 2012;61:271-77.
24Fiadjoe JE, Stricker PA, Hackell RS, Salam A, Gurnaney H, Rehman MA, et al. The efficacy of the Storz Miller 1 video laryngoscope in a simulated infant difficult intubation. Anesth Analg 2009;108:1783-6.
25Vanderhal AL, Berci G, Simmons CF Jr, Hagiike M. A videolaryngoscopy technique for the intubation of the newborn: Preliminary report. Pediatrics 2009;124:e339-46.
26Mutlak H, Rolle U, Rosskopf W, Schalk R, ZacharowksiK, Meininger D, et al. Comparison of the truviewinfant EV02 PCDTM and C-MAC video laryngoscope with direct Macintosh laryngoscopy for routine tracheal intubation in infants with normal airways. Clinics 2014;69:23-7.
27Gupta A, Kamal G, Gupta A, Sehgal N, Bhatla S, Rajeev Kumar R. Comparative evaluation of CMAC and truview picture capture device for endotracheal intubation in neonates and infants undergoing elective surgeries: A prospective randomized control trial. Pediatric Anesthesia 2018;28:1148-53.
28Jain D, Mehta S, Gandhi K, Arora S, Parikh B, Abas M. Comparison of intubation conditions with CMAC miller videolaryngoscope and conventional miller laryngoscope in lateral position in infants: A prospective randomized trial. Pediatr Anesth 2018;28:226-30.
29Moussa A, Luangxay Y, Tremblay S, Lavoie J, Aube G, Savoie E. Videolaryngoscope for teaching neonatal endotracheal intubation: A randomized controlled trial. Pediatrics 2016;137:1-8.
30Bonfils P. Difficult intubation in Pierre-Robin children, a new method: The retromolar route [in German]. Anaesthesist 1983; 32:363-7.
31Halligan M, Charters P. A clinical evaluation of the bonfils intubation fibrescope. Anaesthesia 2003;58:1087-91.
32Liao X, Xue FS, Zhang YM. Tracheal intubation using the bonfils intubation fibrescope in patients with a difficult airway. Can J Anaesth 2008;55:655-6.
33Bein B, Wortmann F, Meybohm P, Steinfath M, Scholz J, Dörges V. Evaluation of the pediatric Bonfils fiberscope for elective endotracheal intubation. Paediatr Anaesth 2008;18:1040-4.
34Houston G, Bourke P, Wilson G, Engelhardt T. Bonfils intubating fibrescope in normal paediatric airways. Br J Anaesth 2010;105:546-7.
35Kaufmann J, Laschat M, Engelhardt T, Hellmich M, Wappler F. Tracheal intubation with the bonfils fiberscope in the difficult pediatric airway: A comparison with fiberoptic intubation. Pediatr Anesth 2014;25:372-8.
36Vlatten A, Aucoin S, Litz S, Acmanus BM, Soder C. A comparison of bonfils fiberscope-assisted laryngoscopy and standard direct laryngoscopy in simulated difficult pediatric intubation: A manikin study. Pediatric Anesthesia 2010;20:559-65.
37Laschat M, Kaufmann J, Wappler F. Management of a difficult airway in a child with partial trisomy 1 mosaic using the pediatric Bonfils fiberscope. Paediatr Anaesth 2010;20:199-201.
38Aucoin S, Vlatten A, Hackmann T. Difficult airway management with the Bonfils fiberscope in a child with Hurler syndrome. Paediatr Anaesth 2009;19:421-2.
39Riveros R, Sung W, Sessler DI, Sanchez IP, Mendoza ML, Mascha EJ, et al. Comparison of the truview PCD and the Glidescope video laryngoscopes with direct laryngoscopy in pediatric patients: A randomized trial. Can J Anesth 2013;60:450-7.
40Cooper RM. Complications associated with the use of the GlideScope® videolaryngoscope. Can J Anesth 2007;54:54-7.
41Nestler C, Reske P, Reske A, Pethke H, Koch T. Pharyngeal wall injury during videolaryngoscopy assisted intubation. Anesthesiology 2013;118:709.
42Leong WL, Lim Y, Sia AT. Palatopharyngeal wall perforation during Glidescope intubation. Anaesth Intensive Care 2008;36:870-4.
43Lee J, Park Y, Byon H, Han W, Kim H, Kim C, et al. A comparative trial of the GlideScope® video laryngoscope to direct laryngoscope in children with difficult direct laryngoscopy and an evaluation of the effect of blade size. Anesth Analg 2013;117:176-81.
44Karsli C, Armstrong J, John J. A comparison between the GlideScope®video laryngoscope and direct laryngoscope in pediatric patients with difficult airways—Apilot study. Anaesthesia 2010;65:353-7.
45Kim J, Na H, Bae J, Kim D, Kim H, Kim C, et al. GlideScope® video laryngoscope: A randomized clinical trial in 203 paediatric patients. Br J Anaesth 2008;101:531-4.
46Armstrong J, John J, Karsli C. A comparison between the GlideScope video laryngoscope and direct laryngoscope in paediatric patients with difficult airways – A pilot study. Anaesthesia 2010;65:353-7.
47Karsli C, Der T. Tracheal intubation in older children with severe retro/micrognathia using the GlideScope cobalt infant video laryngoscope. Paediatr Anaesth 2010;20:577-8.
48Fiadjoe JE, Gurnaney H, Dalesio N, Sussman E, Zhao H, Zhang X. A prospective randomized equivalence trial of the GlideScope Cobalt®video laryngoscope to traditional direct laryngoscopy in neonates and infants. Anesthesiology 2012;116:622-8.
49Kim, H, Kim, J, Kim H, Kim C, Kim S. A comparison of GlideScope® videolaryngoscopy and direct laryngoscopy for nasotracheal intubation in children. Pediatric Anesthesia 2011;21:417-21.
50Sylvia MJ, Maranda L, Harris KL, Thompson J, Walsh BM. Comparison of success rates using video laryngoscopy versus direct laryngoscopy by residents during a simulated pediatric emergency. Simul Healthc 2013;8:155-61.
51Rabiner JE, Auerbach M, Avner JR, Daswani D, Khine H. Comparison of GlideScope videolaryngoscopy to direct laryngoscopy for intubation of a pediatric simulator by novice physicians. Emerg Med Int 2013;2013:407547.
52Park R, Peyton JM, Fiadjoe JE, Hunyady AI, Kimball T, Zurakowski D, et al. The efficacy of GlideScope® videolaryngoscopy compared with direct laryngoscopy in children who are difficult to intubate: An analysis from the paediatric difficult intubation registry. Br J Anaesth 2017; 119:984-99.
53Matsumoto S, Asai T, Shingu K. Truview video laryngoscope in patients with difficult airways. Anesth Analg 2006;103:492-3.
54Singh R, Singh P, Vajifdar H. A comparison of truview infant EVO2 laryngoscope with the miller blade in neonates and infants. Paediatr Anaesth 2009;19:338-42.
55Wang P, Huang C, Lee Y, Chen T, Lai H. Comparison of 3 video laryngoscopes with the Macintosh in a manikin with easy and difficult simulated airways. Am J Emerg Med 2013;31:330-8.
56Inal MT, Memis D, Kargi M, Oktay Z, Sut N. Comparison of truView EVO2 with miller laryngoscope in paediatric patients. Eur J Anaesth 2010;27:950-4.
57Khan R, Kaul N, Gupte S, Hinai FSAA. Truview PCDTM eases laryngoscopy and tracheal intubation in patient with cleft lip, palate, and protruding premaxilla. Pediatr Anesth 2011;21:1268-81.
58Al-Abri ASZ, Khan RM, Haris A, Kaul N. Successful airway management in a patient with Goldenhar's syndrome using truview PCD® laryngoscope. Pediatr Anesth 2012;22:1224-9.
59Singh R, Kumar N, Jain A. A randomised trial to compare truview PCD®, C-MAC® and Macintosh laryngoscopes in paediatric airway management. Asian J Anesthesiol 2017;55:41-4.
60Dhonneur G, Abdi W, Amathieu R, Ndoko S, Tual L. Optimising tracheal intubation success rate using the Airtraq laryngoscope. Anaesthesia 2009;64:315-9.
61Péan D, Desdoits A, Asehnoune K, Lehus C. Airtraq laryngoscope for intubation in treacher collins syndrome. Pediatr Anesth 2009;19:695-715.
62Holm-Knudsen R, White J. The Airtraq may not be the solution for infants with difficult airways. Pediatr Anesth 2010;20:367-79.
63Hirabayashi Y, Shimada N. Airtraq optical laryngoscope: Initial clinical experience in 20 children. J Anesth 2010;24:148-9.
64Maharaj CH, O'Croinin D, Curley G, Harte BH, Laffey JG. A comparison of tracheal intubation using the Airtraq or the Macintosh laryngoscope in routine airway management: A randomised, controlled clinical trial. Anaesthesia 2006;61:1093-9.
65Nileshwar A, Garg V. Comparison of Bullard laryngoscope and short-handled Macintosh laryngoscope for orotracheal intubation in pediatric patients with simulated restriction of cervical spine movements. Paediatr Anaesth 2010;20:1092-7.
66Malin E, Montblanc JD, Ynineb Y, Marret E, Bonnet F. Performance of the Airtraq laryngoscope after failed conventional tracheal intubation: A case series. Acta Anaesthesiol Scand 2009;53:858-63.
67Healy DW, Maties O, Hovord D, Kheterpal S. Videolaryngoscopy in successful orotracheal intubation. BMC Anesthe 2012;12:32.
68Turkstra TP, Pelz DM, Jones PM. Cervical spine motion: A fluoroscopic comparison of the AirTraq laryngoscope versus the Macintosh laryngoscope. Anesthesiology 2009;111:97-101.
69Dimitriou VK, Zogogiannis ID, Liotiri DG. Awake tracheal intubation using the Airtraq laryngoscope: A case series. Acta Anaesthesiol Scand 2009;53:964-7.
70Vlatten A, Fielding A, Bernard A, Litz S, MacManus B, Soder C. Comparison of the Airtraq laryngoscope to the direct laryngoscopy in the pediatric airway. J Pediatr Intensive Care 2012;1:71-6.
71White MC, Marsh CJ, Beringer RM, Nolan JA, Choi AYS, Medlock KE, et al. A randomized, controlled trial comparing the Airtraq™ optical laryngoscope with conventional laryngoscopy in infants and children. Anaesthesia 2012;67:226-31.
72Di Marco P, Scattoni L, Spinoglio A, Luzi M, Canneti A, Pietropaoli P, et al. Learning curves of the Airtraq and the Macintosh laryngoscopes for tracheal intubation by novice laryngoscopists: A clinical study. Anesth Analg 2011;112:122-5.
73Tampo A, Suzuki A, Sako S, Kunisawa T, Iwasaki H, Fujita S. A comparison of the Pentax Airway ScopeTM with the AirtraqTM in an infant manikin. Anaesthesia 2012;67:881-4.
74Lu Y, Jiang H, Zhu YS. Airtraq laryngoscope versus conventional Macintosh laryngoscope: A systematic review and meta-analysis. Anaesthesia 2011;66:1160-7.
75Ali QE, Amir SH, Firdaus U, Siddiqui OA, Azhar AZ. A comparative study of the efficacy of pediatric AirtraqTM with conventional laryngoscope in children. Minerva Anestesiol 2013;79:1366-70.
76Shippey B, Ray D, McKeown D. Use of the McGrath videolaryngoscope in the management of difficult and failed tracheal intubation. Br J Anaesth 2008;100:116-9.
77Flores AS, Garber SM, Niesen AD, Long TR, LynchJJ, Wass CT. Clinical application of a novel video camera laryngoscope: A case series venturing beyond the normal airway. J Clin Anesth 2010;22:201-4.
78Tsujimoto T, Tanaka S, Yoshiyama Y, Sugiyama Y, Kawamata M. Successful intubation using MCGRATH MAC in a patient with Treacher Collins syndrome. Middle East J Anesthesiol 2014;22:523-5.
79Cakirca M, Bektas M, Demir A, Basar H, Baltaci B. A comparison of the efficacy of Macintosh laryngoscope, truview EVO2 and efficacy of McGrath videolaryngoscope in paediatric cases. Anesth Analg 2016;3S:247-8.
80Marciniak B, Fayoux P, Laffargue A, Hébrard A, Krivosic-Horber R. Use of the McGrath® series 5 portable video laryngoscope for tracheal intubation in children. Anesthesiology 2008;109:A785.
81Ross M, Baxter A. Use of the new McGrath® MAC size-1 paediatric videolaryngoscope. Anaesthesia 2015;70:1206-20.
82Szarpak L, Truszewski Z, Czyzewski L, Gaszynski T, Rodríguez-Núñez A. A comparison of the McGrath-MAC and Macintosh laryngoscopes for child tracheal intubation during resuscitation by paramedics. A randomized, crossover, manikin study. Am J Emerg Med 2016;34:1338-41.
83Marcin M, Jacek S, Marek D, Steve L. A comparison of McGrath MAC® and standard direct laryngoscopy in simulated immobilized cervical spine pediatric intubation: A manikin study. Eur J Pediatr 2017;176:779-86.
84Jarvis JL, McClure SF, Johns D. EMS intubation improves with King Vision video laryngoscopy. Prehosp Emerg Care 2015;19:482-9.
85Jagannathan N, Hajduk J, Sohn L, Huang A, Sawardekar A, Albers B, et al. Randomized equivalence trial of the King Vision aBlade videolaryngoscope with the Miller direct laryngoscopefor routine tracheal intubation in children<2 yr of age. Br J Anaesth 2017;118:932-7.
86Kriege M, Pirlich N, Ott T, Wittenmeier E, Dette F. A comparison of two hyperangulated video laryngoscope blades to direct laryngoscopy in a simulated infant airway: A bicentric, comparative, randomized manikin study. BMC Anesthesiol 2018;18:119.
87Akihisa Y, Maruyama K, Koyama Y, Yamada R, Ogura A, Andoh T. Comparison of intubation performance between the King vision and Macintosh laryngoscopes in novice personnel: A randomised, crossover manikin study. J Anesth 2014;28:51-7.
88Oakley E, Stocker S, Staubli G, Young S. Using video recording to identify management errors in pediatric trauma resuscitation. Pediatrics 2006;117:658-64.
89Sakles JC, Mosier J, Hadeed G, Hudson M, Valenzuela T, Latifi R. Telemedicine and telepresence for prehospital and remote hospital tracheal intubation using a GlideScope® videolaryngoscope: A model for tele-intubation. Telemed J E Health 2011;17:185.
90Sun Y, Lu Y, Huang Y, Jiang H. Pediatric video laryngoscope versus direct laryngoscope: A meta-analysis of randomized controlled trials. Paediatr Anaesth 2014;24;1056-65.