INTRODUCTION

Fiber-optic and video intubating stylets are novel intubating devices that permit visualization of the glottis by way of an image conveyed to an eyepiece or video screen from a distally positioned video or fiber-optic image source. Therefore, they do not require a direct line of sight from the operator’s eye to the glottis, as must occur for successful direct laryngoscopy. Distinct from the video laryngoscopes (see Chapter 14) and optical devices (Chapter 15), the fiber-optic and video stylets are intended to have the endotracheal tube (ETT) mounted directly over them, as for any conventional stylet, and are used to guide the tube through the cords and into the trachea under continuous visualization. Unlike flexible fiber-optic devices, these devices are rigid or semirigid and include a fiber-optic bundle or video apparatus enclosed in a preformed, curved steel stylet. They are designed to navigate around the tongue and traverse the hypopharynx to visualize laryngeal structures, often with minimal mouth opening or neck mobility. Their use may offer advantages in patients with anatomic impediments to direct laryngoscopy, such as a high larynx, cervical spine immobility, or limited mouth opening. Also, rigid stylets do not have any control mechanisms like their flexible fiber-optic counterparts and thus are typically easier to maneuver, especially for nonexperts. Rigid stylets have nonmalleable curved metal sheaths, the shape of which cannot be altered, whereas semirigid devices, although not flexible, can be bent slightly to alter their angulation and thus fit the particular airway geometry of each patient.

Semirigid fiber-optic stylets include the Clarus Shikani optical stylet (SOS) and the Clarus Levitan scope (Clarus Medical, Minneapolis, MN). The predominant semirigid video stylet is the Clarus Video System (CVS). Rigid stylets include the Bonfils Retromolar Intubation Fiberscope (Karl Storz Endoscopy, Tuttlingen, Germany) and the Video Rigid Flexible Laryngoscope (RIFL) (AI Medical Devices, Inc., Williamston, MI). New intubating stylets, all similar in shape and principle, are appearing on the market regularly.

These devices are unusual emergency department (ED) tools and are not a routine part of emergency airway management; however, they have potential as adjunctive devices for the difficult airway especially when mouth opening is limited, as a method of awake intubation, or as rescue devices for the failed airway. They may also serve an expanding role in airway training because they all have video displays or are easily adapted for video by attachment of an eyepiece video camera adapter that transmits images to a video monitor.

The Clarus Shikani is a semirigid stylet containing fiber-optic bundles for light and image transmission (Fig. 17-1). The stylet, rounded distally to an angle of about 70° to 80°, ends proximally in a high-resolution, fixed-focus eyepiece. The adult stylet can accommodate ETTs of 5.5 mm internal diameter (ID) or larger. A pediatric version is available and accommodates tubes of 3.0 to 5.0 mm ID. A bright halogen light is powered from the attached handle, which holds four AA batteries, but the stylet is also compatible with green specification fiber-optic laryngoscope handles or remote light sources through a fiber-optic cable. A camera can be attached to the eyepiece and the image displayed on a video monitor for teaching purposes. Additionally, a proprietary eyepiece adapter is available that can hold a variety of smartphones displaying images when the phone is in camera mode (Fig. 17-2). A push button power switch can be found on the top of the handle. An adjustable tube stop is mounted on the proximal portion of the stylet to hold the ETT in the desired position and prevent the tip of the stylet from protruding from the distal end of the ETT. The tube stop incorporates an oxygen port, permitting insufflation of oxygen during laryngoscopy. This helps prevent contamination of the tip of the stylet and can mitigate oxygen desaturation during prolonged intubation attempts. The malleable distal section of the stylet can be adjusted by hand, increasing or decreasing the angle of the bend to conform to the patient’s anatomy. The manufacturer also sells a stylet bending guide that helps to bend the stylet in a smooth curve and helps avoid damage to the fiber-optic bundles by bending it too acutely.

To prepare the Clarus Shikani, an ETT is loaded on the stylet, with the distal end of the stylet positioned just proximal to the ETT tip, and stabilized in this position by adjusting the tube stop proximally. Lubrication of the stylet will facilitate tube withdrawal when the intubation is completed, but care should be taken not to contaminate the tip of the scope, which can obscure the image. Before insertion, the stylet tip should be warmed with either warm saline or a warm blanket. Antifog solution should be applied to minimize fogging during the intubation attempt. The device is held by the fingertips and thumb of the dominant hand, with the handle cradled in the web space between the thumb and index finger and the pads of all other fingers resting on the anterior part of the eyepiece and proximal stylet. Despite its appearance, the handle should not be gripped in the hand, but is properly held in the fashion demonstrated in Figure 17-3. The ETT–stylet combination is then inserted into the mouth in the midline and advanced into the hypopharynx under direct vision, not by using the eyepiece. The entire stylet is then advanced along its curve gently around the base of the tongue. A firm jaw lift/tongue pull during insertion will lift the soft tissues of the upper airway and create some anatomic space through which to navigate the scope. The operator should begin to visualize glottic structures through the eyepiece as the tip navigates the base of the tongue. The epiglottis should quickly come into view. Guide the stylet under the epiglottis to visualize the laryngeal inlet. The operator should then attempt to advance the tip of the stylet through the cords. Typically, the operator can advance the scope 1 to 2 cm into the laryngeal inlet. A common error is to advance the fiber-optic tip too far into the hypopharynx as it is inserted, giving a view of the posterior aspect of the hypopharynx or upper esophagus. To avoid this, ensure that the primary motion of the scope is initially rotation around the tongue and not advancement into the hypopharynx. If no anatomic structures are recognized in the initial insertion, it is best to withdraw the stylet, ensure positioning in the midline, ensure proper elevation of the tongue and mandible, and attempt slow reinsertion, identifying the epiglottis or other laryngeal structures as the assembly is advanced. As with other intubating stylets, the instrument can be used in conjunction with direct laryngoscopy. For example, when an unanticipated grade 3 direct laryngoscopy (epiglottis only) occurs, the Clarus Shikani can be inserted under the epiglottis during direct laryngoscopy, and the glottic opening can then be located by looking through the eyepiece. When the stylet is used as an adjunct to direct laryngoscopy, an assistant may help loosen the tube from the tube stop and advance the ETT into the trachea under the guidance of the operator. With either technique, the ETT–stylet is advanced through the cords as the operator looks through the eyepiece, and then the ETT is held in place as the stylet is withdrawn by the operator, using a large circular motion, in an arc initially upward toward the ceiling in the axis of the proximal end of the tube, and then continuing toward the patient’s chest and feet, following the curve of the stylet to facilitate removal (Fig. 17-4). Tube placement confirmation is with end-tidal carbon dioxide (CO₂), auscultation, and chest radiography, as for any other methods of intubation.

• FIGURE 17-1. Shikani optical stylet.

• FIGURE 17-2. Levitan optical stylet with optional eyepiece attachment for holding smartphones.

• FIGURE 17-3. Shikani optical stylet—in hand.

The Clarus Shikani is advertised as being useful for the management of difficult and routine airways, with the video and smartphone capability facilitating larger image displays, airway management supervision, and teaching. In the teaching setting, coupling the device with a video system can greatly enhance success by allowing the instructor to help guide and, if necessary, reorient the learner.

The primary limitation of the Clarus Shikani is its inability to maintain clear vision occasionally because of fogging or the presence of secretions or blood. Fogging can be greatly reduced by warming the lens and applying antifog solution, as described previously. Although secretions, vomitus, or blood can obscure the distal lens of the scope, two key design elements come into play:

1. The patient is typically supine, and with the jaw thrust and tongue pull, most of the manipulation of the scope is occurring anterior to the location of the pooled liquids.

2. 

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