Video Laryngoscopy and The Pediatric Airway

Cheryl K. Gooden, MD

North American Partners in Anesthesia
Pediatric Anesthesiologist
Children’s Pavilion
Bronx-Lebanon Hospital Center
Bronx, New York

The past decade has seen many anesthesiologists embrace the use of video laryngoscopy in pediatric patients. A review of their use is presented, as is information on some of the devices themselves.

Introduction

The use of video laryngoscopy (VL) by anesthesiologists in the pediatric patient has been available for a little more than a decade. From the vantage point of a pediatric anesthesiologist who has managed numerous difficult airways, we have certainly come a long way in a relatively short time with the arrival of VL. That said, in the 1980s, video technology made its appearance in the field of surgery.¹ The use of this technology by our surgical colleagues has increased enormously over this period. Since the advent of video technology, anesthesia providers have learned how this tool can enhance our ability to manage the airway.

The introduction of VL technology has provided the laryngoscopist and other clinicians with an all-inclusive view of the airway. The result is a greater appreciation for the anatomy, for 2 reasons: First, VL offers an expanded view of the airway compared with direct laryngoscopy² (DL) and second, the view provided by VL is a high-resolution one. These unique features demonstrate the overall appeal of VL and help explain why it has so rapidly become a part of the airway armamentarium.

This article is an update on VL and its application in the neonate, infant, and child less than 8 years of age.

Implications of Pediatric Airway Anatomy For Airway Management

Regardless of the choice of device used to manage the airway, clinicians must understand the pediatric airway anatomy. There are several critical differences between the infant and child airway anatomy and that of an adult.³ Several of these developmental differences are summarized in Table 1. Notably, recently published studies suggest that the narrowest part of the pediatric airway may actually be at the level of the vocal cords.^4-6

Table 1. Developmental Differences In the Pediatric Airway Compared With the Adult Head (occiput) Relatively large Tongue Large relative to the size of the mouth Larynx More cephalad in the infant (C2-C3) until it approaches that of the adult(C4-C5) Epiglottis Narrow, omega-shaped, and projects above the glottic opening Vocal cords Slant anteriorly and rostrally Narrowest part of the larynx Traditional teaching: Cricoid cartilage Recent studies: Vocal cords

Direct Versus Video Laryngoscopy

Anesthesia providers are knowledgeable and experienced in the techniques of DL. The past decade has resulted in many anesthesiologists becoming clinically adept at VL in the pediatric airway. Most laryngoscopists would agree that the skill set differs between DL and VL, to some extent. In addition, compared with DL, VL can provide an expanded view of the airway from the oropharynx to the glottic opening.^7,8

The technique of mouth opening is similar in DL and VL. However, subsequent steps diverge between the 2 techniques. The VL blade is inserted midline with the avoidance of a tongue sweep. The airway manager views the display monitor or other screen as the laryngoscope blade is gently lifted and advanced until the larynx becomes visible. As with DL, external laryngeal manipulation may be necessary to improve the laryngeal view. Viewing the monitor while advancing the video laryngoscope demands fine hand-eye coordination, a skill that may require practice to polish.⁹ In general, however, the nuances of using a VL device can be acquired over time.¹⁰

Video Laryngoscopy in Pediatrics

A decade later, several studies, case reports, and correspondence demonstrate the successful use of VL in pediatric patients.^11-19 The evidence supporting the use of VL in the adult patient population is far greater than in pediatrics. For the most part, VL provides better views of the larynx and surrounding airway anatomy than DL. In a prospective randomized trial, Fiadjoe and colleagues compared the GlideScope Cobalt video laryngoscope with DL in infants.¹⁹ The investigators concluded that the use of the GlideScope resulted in faster time to obtaining superior views, but endotracheal tube (ETT) entry through the glottis took longer than with DL.¹⁹

Table 2. Video Laryngoscopes for Pediatrics Device (Manufacturer) Classification Patient Size Features C-MAC, C-MAC Pocket Monitor (Karl Storz) Video laryngoscope Neonate, infant, child Reusable Miller 0 and 1 Macintosh 2, D-blade Ped (specifically for the difficult airway) GlideScope AVL, GlideScope Ranger (Verathon Medical) Video laryngoscope Neonate, infant, child Video baton accommodates single-use STATs (blades; GVL 0, 1, 2, 2.5) McGrath MAC (Medtronic) Video laryngoscope Child MAC 2 blade Rusch Airtraq SP (Teleflex) Channeled device, crossovera Infant, child Single use Infant (size 0) fits ETT sizes 2.5-3.5 Pediatric (size 1) fits ETT sizes 4.0-5.5 TruView PCD (Teleflex) Crossovera Neonate, infant, child Four reusable blade sizes (0, 1, 2, 3) a Crossover = optical laryngoscope with video capability

Types of Video Laryngoscopes

Several video laryngoscopes are commercially available for use in the pediatric patient (Table 2). Some of these devices may be used in the smallest patients, including premature infants and neonates (Figure 1). A few of the devices listed in Table 2 are not, in the strictest sense, video laryngoscopes. However, with the addition of a camera and monitor connection, these devices “cross over” and have a similar function. During the past decade, there is no question that VL technology has made significant advancements. The need for this technology in the pediatric patient population is just as great as in adults.

Rusch Airtraq SP

The Airtraq is a non-reusable optical laryngoscope that can accommodate a camera to provide the quality of VL (Figure 2). This system can integrate with the A360 Wi-Fi camera that shares real-time images with smartphones, tablets and personal computers. In addition, the system has a smartphone adapter that allows use of the phone’s high-definition (HD) camera. This device has application for the routine or difficult airway management of the infant and child. The Airtraq consists of a light source, antifog system, and 2 channels. The optical channel contains the high-tech optical system and the guiding channel accommodates the ETT.

Use of the Airtraq begins by turning on the light source. Next, the ETT should be lubricated and placed within the guiding channel. The device is positioned midline into the opened mouth. At this point, the laryngoscopist will start looking through the eyepiece or at the monitor as the device is advanced through the oropharynx to identify the epiglottis. Similar to laryngoscopy with a Macintosh blade, the distal end of the Airtraq is inserted into the vallecula. The Airtraq is slightly lifted with motion from side to side to obtain a centered image of the vocal cords. It is at this point that the ETT is inserted through the vocal cords; use of a stylet is unnecessary. Once the ETT cuff has been inflated, the ETT should be removed from the guiding channel. The literature demonstrates the successful use of the Airtraq in a number of challenging pediatric clinical scenarios.^20-23

GlideScope

The GlideScope was introduced for pediatric use in 2005. Since its introduction, the neonatal and pediatric video laryngoscope blades have evolved through several generations. Initially, this device provided black-and-white images, but for several years now have been in color. In addition, the quality of the images is of a high resolution. The GlideScope was developed for the management of the difficult airway, but now for many users of this device, it has become part of routine airway management for pediatric patients of all ages.

The basic design of the GlideScope includes the blade and display monitor. The video laryngoscope blade consists of a camera and light source embedded along its inferior aspect.⁸ The blade has a 60-degree angle, and with its camera, provides views of the supraglottic airway and adjacent structures. The airway image is captured on a display unit that accompanies this system, or with other compatible designs.^8,24

The GlideScope AVL system integrates with non-reusable STATs (plastic blades) that slide over the baton.²⁵ This system has the advantage over the original system of well-suited blades for the preterm, neonate, or infant patient. The GlideScope Ranger system is the most versatile, and quite often is used in the prehospital setting. The GlideScope Titanium system is the latest system available for adults, but is not yet released in pediatric sizes; that release is reported to be scheduled for the second half of 2016.

After powering on the GlideScope and opening the patient’s mouth, the blade is inserted midline around the base of the tongue. The laryngoscopist then advances the blade toward the valleculla, observing the progress on the display monitor. When the vocal cords appear on the monitor, a styletted ETT (mimicking the blade angle or one likened to a “hockey stick”) is advanced through the opening. At the glottis opening, the stylet is removed while further advancing the ETT through the trachea. Following this action, the video laryngoscope blade is removed.

To date, there are more cases in the literature citing use of the GlideScope in pediatric patients than any other video laryngoscope.^{11-13,15-18,26} The largest pediatric study of the use of the GlideScope, by Kim et al,¹³ included 203 children. The investigators concluded that the device provided a view of the larynx that was equal or superior to that of conventional laryngoscopy. They also found that the time required for intubation was longer using the GlideScope.¹³

C-MAC

The C-MAC is a lightweight, compact system that consists of a monitor, electronic module and video laryngoscope blade (Figure 4). The electronic module connects the video laryngoscope and monitor. For the laryngoscopist, this system offers the familiarity of the Miller and Macintosh blades. The C-MAC has 4 blades for pediatric use. The newest of these blades is the D-Blade Ped that was developed for the difficult pediatric airway. The C-MAC Pocket Monitor is quite portable and accommodates the same pediatric blade sizes as the primary system.

The literature is quite sparse with regard to the use of the C-MAC system in pediatrics. A reported case documents the successful intubation of a neonate with dysmorphic facies using a Miller size 1 video laryngoscope blade.²⁷ The authors describe a Cormack-Lehane grade 3 view with DL and a significantly improved grade 1 view with VL.²⁷

TruView PCD

The TruView PCD is a reusable optical laryngoscope with crossover capability through a camera attachment connected to a monitor (Figure 5). This device contains an optical system that offers a magnified laryngeal view. A side port on the blade for insufflation of oxygen ensures that secretions do not obstruct the view.

As with other devices described in this article, the mouth is opened and the TruView PCD blade is inserted midline. The blade is advanced under visualization while moving the tongue to the left. Advancement of the blade continues until the epiglottis becomes visible (either through the optics or on the video monitor), whereupon the laryngoscopist gently lifts the device. A styletted ETT is positioned along the side of the blade. The ETT is advanced until the tip is visualized; further advancement slightly up and to the left, toward the distal end of the blade, can follow. The ETT is inserted through the vocal cords, and the stylet is removed before advancing the tube into the trachea.

A randomized crossover study performed by Hippard et al²⁸ examined whether the conventional Miller #1 blade, the GlideScope Cobalt AVL, or the TruView PCD had the shorter time to endotracheal intubation when used by experienced pediatric anesthesiologists in manikins with normal and difficult pediatric airways. The investigators found less success and longer times to intubation with the TruView PCD and the GlideScope Cobalt AVL than with the conventional Miller blade.²⁸ The investigators felt the reasons for this might include more experience with DL or problems with manikin design.

McGrath MAC

The McGrath MAC enhanced direct laryngoscope provides the laryngoscopist with the option to use the device as either DL or VL. The McGrath MAC EDL uses the traditional curved Macintosh blade.²⁹ Similar to the C-MAC, this device integrates a blade that is already familiar to the laryngoscopist.

A case report documents the successful intubation of a neonate using the McGrath MAC 1 blade.³⁰ The authors noted that the same device was used to visualize the vocal cords with both DL and VL, and an improved view was obtained with VL.30 In a randomized controlled trial, Kim and colleagues examined head position and the impact on airway visualization while using the McGrath MAC in pediatric patients.31 The results of their study suggest that visualization of the larynx improves when the external auditory meatus and sternal notch are in alignment in the horizontal plane.31

Conclusion

The past decade reflects the fact that VL has gained popularity and interest as an airway device for use in the pediatric patient.11,22,26-31 Some anesthesiologists have incorporated the use of VL into their routine airway management of the infant and child. For others, VL may be reserved for only the difficult pediatric airway. The impact of VL on airway management is significant and continues to expand.

References

1. Das K, Rothberg M. Thoracoscopic surgery: historical perspectives.Neurosurg Focus. 2000;9(4):e10.
2. Cooper R. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway.Can J Anesth.2003;50(6):611-613.
3. Wheeler M, Cot C, Todres I. The pediatric airway. In: Coté C, Lerman J, Todres I, eds.A Practice of Anesthesia for Infants and Children. Philadelphia, PA: Saunders Company; 2009:237-273.
4. Litman R, Weissend E, Shibata D, et al. Developmental changes of laryngeal dimensions in unparalyzed, sedated children.2003;98(1):41-45.
5. Dalal P, Murray D, Messner A, et al. Pediatric laryngeal dimensions: an age-based analysis.Anesth Analg.2009;108(5):1475-1479.
6. Wani T, Bissonnette B, Malik M, et al. Age-based analysis of pediatric upper airway dimensions using computed tomography imaging.Pediatr Pulmonol.2016;51(3):267-271.
7. Kaplan M, Ward D, Hagberg C, et al. Seeing is believing: the importance of video laryngoscopy in teaching and in managing the difficult airway.Surg Endosc.2006;20 (Suppl 2):S479-S483.
8. Cooper R, Pacey J, Bishop M, et al. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients.Can J Anesth.2005;52(2):191-198.
9. Lim TJ, Lim Y, Liu E. Evaluation of ease of intubation with the GlideScope or Macintosh laryngoscope by anesthetists in simulated easy and difficult laryngoscopy. 2005;60(2):180-183.
10. Lim Y, Lim T, Liu E. Ease of intubation with the GlideScope or Macintosh laryngoscope by inexperienced operators in simulated difficult airways.Can J Anesth. 2004;51(6):641-642.
11. Xue F, Tian M, Liao X, et al. Safe and successful intubation using the GlideScope videolaryngoscope in children with craniofacial anomalies.Plast Reconstr Surg.2009;123(3):1127-1129.
12. Taub PJ, Silver L, Gooden CK. Use of the GlideScope for airway management in patients with craniofacial anomalies.Plast Reconstr Surg.2008;121(4):237e-238e.
13. Kim J, Na H, Bae J, et al. GlideScope video laryngoscope: a randomized clinical trial in 203 paediatric patients.Br J Anaesth. 2008;121(4):531-534.
14. Xue F, Tian M, Liao X, et al. Safe and successful intubation using s Storz video laryngoscope in management of pediatric difficult airways.Pediatr Anesth.2008;18(12):1251-1252.
15. Jagannathan N, Sohn L, Suresh S. Glossopharyngeal nerve blocks for awake laryngeal mask airway insertion in an infant with Pierre-Robin syndrome: can a GlideScope come to the rescue?Pediatr Anesth.2009;19(2):189-190.
16. Redel A, Karademir F, Schlitterlau A, et al. Validation of the GlideScope video laryngoscope in pediatric patients.Pediatr Anesth.2009;19(7):667-671.
17. Bishop S, Clements P, Kale K, et al. Use of GlideScope Ranger in the management of a child with Treacher Collins syndrome in a developing world setting.Pediatric Anesth.2009;19(7):695-696.
18. Eaton J, Atlies R, Tuchman J. GlideScope for management of the difficult airway in a child with Beckwith-Wiedemann syndrome.Pediatr Anesth.2009;19(7):696-698.
19. Fiadjoe J, Gurnaney H, Dalesio N, et al. A prospective randomized equivalence trial of the GlideScope Cobalt video laryngoscope to traditional direct laryngoscopy in neonates and infants.2012;116(3):622-628.
20. Lejus C, Pichenot V, Péan D, et al. Intubation with an Airtraq of a 7-year-old child with severe cervical burned sequels.Ann Fr Anesth Reanim.2009;28(4):399-400.
21. Péan D, Desdoits A, Asehnoune K, et al. Airtraq laryngoscope for intubation in Treacher Collins syndrome.Pediatr Anesth.2009;19(7):698-699.
22. Vlatten A, Soder C. Airtraq optical laryngoscope intubation in a 5-month-old infant with a difficult airway because of Robin sequence.Pediatr Anesth.2009;19(7):699-700.
23. Srilata M, Jayaram K, Kulkarni D, et al. Airtraq and pediatric cervical spine surgery.J Neurosurg Anesthesiol.2015;27(1):79-80.
24. Doyle DJ. Miniaturizing the GlideScope video laryngoscope system: a new design for enhanced portability.Can J Anesth.2004;51(6):642-643.
25. Jones P, Harle C, Turkstra T. The GlideScope Cobalt video laryngoscope—a novel single-use device.Can J Anesth.2007;54(8):677-678.
26. Trevisanuto D, Fornaro E, Verghese C. The GlideScope video laryngoscope: initial experience in five neonates.Can J Anesth.2006;53(4):423-424.
27. Wald S, Keyes M, Brown A. Pediatric video laryngoscope rescue for a difficult neonatal intubation.Pediatr Anesth.2008;18(12):790-792.
28. Hippard H, Kalyani G, Olutoye O, et al. A comparison of the Truview PCD and the GlideScope Cobalt AVL video laryngoscopes to the Miller blade for successfully intubating manikins simulating normal and difficult pediatric airways.Pediatr Anesth.2016:26(6):613-620.
29. McGrath^®MAC Enhanced Direct Laryngoscope Product Tour. http://www.medtronic.com. Accessed June 12, 2016.
30. Ross M, Baxter A. Use of the new McGrath^®MAC size – 1 paediatric videolaryngoscope.2015;70(10):1206-1207.
31. Kim E, Lee J, Song I, et al. Effect of head position on laryngeal visualization with the McGrath MAC videolaryngoscope in paediatric patients.Eur J Anaesthesiol.2016;33(7):528-534.

Copyright © 2016 McMahon Publishing, 545 West 45th Street, New York, NY 10036