Background
Various types of stylets are commonly available as adjuncts to endotracheal intubation, including the traditional malleable stylet, the gum elastic bougie (see the first video below), optical stylets, and lighted stylets (see the second video below). This article discusses the use of lighted stylets for tracheal intubation.
Lighted stylets available include Light Wand (Vital Signs Inc, Totowa, NJ), Trachlight (Laerdal Medical, Wappingers Falls, NY), Tube Stat lighted stylet (Xomed, Jacksonville, FL), and others. [1, 2] These devices rely on the principle of transillumination of the soft tissues of the neck. The light serves to guide the tube into the larynx; direct visualization of the glottis is not required for successful use. [3]
Intubation under direct vision may be difficult or impossible in 1-3% of surgical patients and 0.05-3.5% of obstetric patients. [4, 5] Light-guided intubation using transillumination has proved to be simple and effective. When the tip of the lightwand is placed inside the glottis, a bright glow can be seen in the anterior soft tissue of the neck. In contrast, if the lightwand is placed in the esophagus, no transillumination is observed.
Benefits of light-guided tracheal intubation include utility in obstructed conditions, low acquisition costs, and disposable components that eliminate the need for disinfection of the equipment. A distinct disadvantage is that room lights must be dimmed during the procedure. The procedure also requires a fair amount of user experience. [1, 6, 7, 8, 9]
Indications
A patient with a difficult airway in whom direct laryngoscopy has failed is a candidate for light-guided tracheal intubation. [9, 10] A trauma patient with bleeding in the oropharynx is a prime example.
A patient who has been pharmacologically paralyzed and cannot be intubated with direct laryngoscopy is also a candidate for light-guided tracheal intubation.
The lighted stylet can also be used in successfully completing a difficult nasotracheal intubation. [11] An advantage of this technique over nasotracheal intubation is that it can be used in an apneic patient.
Contraindications
Lighted stylet intubation is a blind approach. Therefore, it should be avoided in patients with an expanding neck mass, oropharyngeal tumors, infections (epiglottitis), morbid obesity (because of the difficulty transilluminating soft tissues of the neck), or airway compromise presumed to be caused by a foreign body.
In addition, since the room lights must be dimmed during the procedure, this device may not be appropriate in certain critical or trauma situations. [1, 12]
Outcomes
In a study involving 62 adult patients who underwent thoracic surgery using double-lumen endobronchial intubation, Chang et al compared the use of a GlideScope with the use of a lighted stylet with respect to intubation time, success rate of first intubation attempt, difficulty of advancing the tube toward the glottis, and postoperative sore throat and hoarseness. [13] They found that the lighted stylet allowed easier advancement of the tube toward the glottis in the oropharyngeal space and a shorter intubation time.
In a randomized clinical study that included 284 patients undergoing general anesthesia, Park et al assessed the effectiveness of a lighted stylet against that of a simple stylet during tracheal intubation with direct laryngoscopy. [14] Compared with the simple stylet, the lighted stylet yielded a higher success rate of tracheal intubation at the first attempt (99% vs 90%) and a lower incidence of mucosal bleeding (13% vs 25%). Total intubation time and degree of postoperative sore throat did not differ significantly between the two groups.
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Insertion technique for lighted stylet intubation.
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Transtracheal light.
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Tracheal intubation (gum elastic bougie). Video courtesy of Therese Canares, MD, and Jonathan Valente, MD, Rhode Island Hospital, Brown University.
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Tracheal intubation (lighted stylet). Video courtesy of Therese Canares, MD, and Jonathan Valente, MD, Rhode Island Hospital, Brown University.
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Trachlight anterior neck. Image courtesy of Lawrence B Stack, MD (http://www.lbstack.com/).
