The exact technique will depend upon the type of lighted stylet or lightwand used. Since this technology varies by the manufacturer, anyone employing these airway adjuncts should be familiar with the equipment and manufacturer's instructions prior to adopting them for use clinically. This text describes the general guidelines for the lighted stylets available at the time of this writing. The reader is urged to take advantage of the teaching videos supplied by some manufacturers.
Check that the light source is working and apply a water-based lubricant to the stylet. Attach a 10 mL syringe to the ET tube cuff inflation port and ensure the integrity of the cuff. Insert the stylet through the ET tube. The tip of the stylet should remain just inside the ET tube so that the stylet does not damage soft tissues.
Bend the tip of the ET tube and stylet just proximal to the cuff or about 3 to 6 cm from the distal end (Figure 17-5). The bend may have to be a little more proximal or distal depending on the length of the patient's neck. Measure the mandibular–hyoid distance in the patient. Place the index finger in the submental space below the chin and determine the number of finger breadths between the mandible and the hyoid bone.5 Typical measurements are one to three finger breadths. Bend the tip of the ET tube and stylet sharply at a site that approximates the mandibular–hyoid distance between the bend and the junction of the lighted tip of the stylet. This is usually 3 to 6 cm from the distal end of the ET tube and just above the cuff. Avoid making the bend at the cuff, if possible, to prevent damaging the cuff. Be sure the bend is about 90° to allow the maximal light intensity to be directed anteriorly.
Stand above or to the side of the patient's head. The lighted stylet, unlike the traditional laryngoscope, can be held in either hand. Lower the bed to facilitate insertion of the lighted stylet. Grasp the patient's jaw with your nondominant hand. Place your thumb on the mandibular molars and your fingers under the body of the mandible. Lift upward and inferiorly to open the jaw, elevate the tongue, and elevate the epiglottis. Grasp the lighted stylet with your dominant hand and turn it on. It is best held with a “pencil-grip” over the proximal ET tube.
Introduce the ET tube from the side of the patient's mouth and bring it to the midline. As the hockey stick-shaped tip is placed over the tongue, the handle will project toward the patient's feet (Figure 17-6A). Advance the tip by moving the handle in a vertical arc toward the patient's head (Figure 17-6B). This will bring the ET tube tip toward the vocal cords. A bright light will be seen in the midline of the neck just below the hyoid bone (Figure 17-7A). If the light is in the submental space, the tip of the ET tube is in the vallecula (Figure 17-7B). If the light is lateral, the tip of the ET tube is lodged in the pyriform sinus (Figure 17-7C). A dull, faint light in the midline signifies that the tip of the ET tube is in the esophagus (Figure 17-7D). If the glowing light is malpositioned, simply withdraw the ET tube, reposition it in the midline, and advance it again.
Insertion of the Trachlight lighted stylet. A. Insert the hockey stick-shaped ET tube and the stylet over the tongue. B. Move the tube in a vertical arc toward the patient's head. As the lighted stylet approaches the trachea, the bright light transilluminates the anterior neck. C. The ET tube is advanced into the trachea.
Appearance of the transilluminated light of the lighted stylet based on the location of the tip. A. Proper placement in the larynx with a bright distinct light in the midline at the level of the thyroid cartilage. With advancement of the ET tube, the light moves down the anterior neck and disappears behind the sternal notch (dashed arrow). B. Incorrect placement in the vallecula causes a submental glow, superior to the hyoid. C. Incorrect placement in the pyriform sinus causes a glow off the midline. D. Incorrect esophageal placement causes a diffuse, dull, or absent light.
Once a bright and discrete light is detected in the midline at the level of the thyroid cartilage (Adam's apple), it is safe to advance the ET tube. If you are using the Trachlight, the manufacturer suggests withdrawing the stylet 10 cm before advancing the ET tube. This makes the distal tip of the ET tube more flexible and helps it make the acute turn before advancing down the trachea.
Advance the ET tube while observing the transilluminating light march down the neck to the suprasternal notch (Figure 17-7A). The light will disappear as the tube passes behind the suprasternal notch. If the glowing light is in the midline and the ET tube is resistant to advancement, the epiglottis is obstructing its advancement. Slightly rock the unit in the sagittal plane (from the patient's head to the feet) to slip the tip of the ET tube under the epiglottis. If resistance is still encountered, remove the lighted stylet. Ventilate the patient with a bag-valve-mask device. Load a smaller ET tube onto the lighted stylet and try again. At the point the light is lost, the tip of the ET tube is appropriately positioned midway between the vocal cords and carina.25 Remove the stylet, inflate the ET tube cuff, confirm proper ET tube placement, secure the ET tube at the lips, and begin ventilating the patient.
Special caution should be used in very thin or very obese patients. In the thin patient, a bright light may be visible even when the stylet is in the esophagus. When the patient is thin, gently rock the light off midline to compare the diffuse dull light to that seen when the light is truly midline. In the obese patient, the extra soft tissue may dull the light. Dim the room lights to facilitate adequate visualization.
The glowing light must maintain a continual brightness to demonstrate tracheal intubation. If the glowing light is briefly lost or dulls and then returns, the ET tube has been misplaced in the esophagus. The brief loss or dulling of the glowing light corresponds to its passage behind the larynx. The return of the bright glowing light corresponds to the ET tube advancing past the larynx and into the esophagus. This is commonly seen in infants, small children, and very thin adults. Gently withdraw the lighted stylet while applying anteriorly directed traction to the tip of the stylet. Stop withdrawing the lighted stylet when the glowing light suddenly intensifies after it exits the esophagus. Readvance the lighted stylet, as previously described, while applying anterior traction on the unit to help it enter the larynx.
The procedure for nasotracheal intubation is similar to orotracheal intubation with the lighted stylet with a few differences. The nasal passages should be treated with a topical anesthetic and a topical decongestant to vasoconstrict the mucosal tissue. The nasal passage may need to be dilated to accommodate the ET tube. Please refer to Chapter 22 for a complete discussion on the preparation of the nasal cavity for intubation. The lighted stylet should have a more gentle curve of about 100° to 120°. The bend to tip length should correspond to the distance from the posterior nasopharynx to the cricothyroid membrane.