Lighted Stylet Assisted Tracheal Intubation 

Various types of stylets are commonly available as adjuncts to endotracheal intubation, including the traditional malleable stylet, the gum elastic bougie, optical stylets, and lighted stylets. This article discusses the use of lighted stylets for tracheal intubation.

Lighted stylets available include Light Wand (Vital Signs Inc, Totawa, NJ), Trachlight (Laerdal Medical, Wappingers Falls, New York), Tube Stat lighted stylet (Xomed, Jacksonville, Fla), 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]

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, 4, 5, 6, 7]}

• A patient with a difficult airway in whom direct laryngoscopy has failed is a candidate for light-guided tracheal intubation.^{[7, 8]} 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.^[9] An advantage of this technique over nasotracheal intubation is that it can be used in an apneic patient.

• 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), and 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, 10]}

• If the patient is awake, spray the oropharynx and hypopharynx with lidocaine or benzocaine (Hurricaine) spray and administer sedation as indicated.
• Topical anesthesia may be achieved by use of lidocaine spray 10%, Cetacaine (benzocaine 14%, tetracaine 2%, butyl aminobenzoate 2%), or Hurricaine (benzocaine 20%).
• Procedural sedation or rapid sequence intubation may also be required.

Equipment for intubation

• Lighted styletTranstracheal light.
• Supplemental oxygen
• Ambu bag
• Suction equipment

Additional necessary equipment/preparation

• Automated blood pressure cuff (set to cycle every 5 min)
• 3-lead ECG monitoring
• Constant pulse oximetry
• Intravenous access

• If cervical spine injury is not a concern, place the patient's head in the sniffing position. If cervical spine injury is a concern, place the patient's head in a neutral position.
• A towel roll beneath the shoulders aids in positioning.

• The practitioner should stand at the head of the patient. If this is not possible, the patient can be approached from either side.
• Insert the lubricated lighted stylet into an endotracheal tube 2.5 mm or larger (pediatric stylets are available) until the bulb lies just distal to the Murphy eye but does not protrude from the end of the tube.
• Bend the tube and stylet in the shape of a hockey stick, with a 90° curve beginning just proximal to the tube cuff.^{[1, 2]}
• Place the patient's head and neck in the neutral position or slightly extended.
• Grasp the patient's jaw near the corner of the mouth using the thumb, index, and middle fingers.
• Lift the jaw to elevate the tongue and epiglottis.Insertion technique for lighted stylet intubation.
• A glow in the midline of the neck indicates the location of the tube tip.

  • Applying cricoid pressure and dimming the lights may enhance transillumination.
  • Positioning is optimal when the glow can be seen in the midline of the neck, just below the level of the thyroid prominence.
• Next, slide the endotracheal tube off while holding the stylet steady and advance into the trachea up to the proper depth.

  • If the glow is located off midline, withdraw the unit 2 cm and reposition as indicated by the light.
  • If a dim or no light is seen, the tube is likely in the esophagus. If this is the case, withdraw the tube, apply cricoid pressure, and, if necessary, extend the head slightly.
• Once the lighted stylet has been removed and the tube placement has been verified by auscultation and capnography, then the endotracheal tube should be secured with a commercially available tube holder or adhesive tape.^{[1, 4, 2]}

• Some investigators suggest that for novices, conventional laryngoscopy may be superior to the use of transillumination with a lighted stylet. However, for practitioners experienced in its use, transillumination can be as reliable as conventional laryngoscopy, and it can be used in apneic patients.
• Positioning is correct when the glow emanates from the midline, just below the level of the thyroid prominence. In extremely thin patients, transillumination may be seen even when the tube is the esophagus. To tell the difference, note that if the tip is in the esophagus, the glow is diffuse, as opposed to the well-circumscribed glow of intralaryngeal placement.
• A controlled study by Muslu et al highlighted the successful use of sonography as an adjunctive method for tracheal tube placement confirmation within 3 seconds of intubation in 150 adult surgical patients. Sonographers were able to successfully identify tracheal tube position in 75 of 75 tracheal placements and 75 of 75 esophageal placements, resulting in sensitivity of 100% and specificity of 100%.^[11]

• No complications directly related to the use of the tracheal light have been cited in the recent literature; this may be a reflection of the limited use of this technique.^{[1, 2]}