The light at the end of the airway
Facing a failed airway can be one of the scariest moments for any emergency physician. Unlike anesthesiologists we don’t have the luxury of canceling cases so we must always be prepared for the worst case scenario. Over the course of the next several months I intend to give you some options to assist in these scenarios.
We’ll begin the reviews of difficult airway devices with my personal favorite, the light wand, or more particularly the Laerdal Trachlight. I’ll be honest here, I don’t just like the Trachlight, I love it. It’s slick, it’s elegant, and it can pull your butt out of a jam. Plus, you are sure to impress when you ask for the lights to be lowered in the middle of a critical situation and start the light show. That said, while a versatile airway tool, light wands have a steep learning curve and suffer from rapid skill degradation when not used frequently. For this reason, even though light wands have been around for over a decade they are often overlooked by EP’s. Let’s take a fresh glance at this often-overlooked tool.
The principle behind light wands is transillumination of the trachea through the soft tissues of the neck as the stylet passes through the trachea. Light wands are simply stylets with a lighted tip over-which an endotracheal tube is placed similar to standard stylets. The stylet is then bent at a 90˚ angle. Keep in mind that the length from the tip to the bend should approximate the distance from the mouth to the cricoid membrane. The technique used when intubating with a lighted stylet is a completely blind one with the user at the head of the bed and the bed lowered to waist height. The patient is sedated and paralyzed as you would any RSI case. With the wand held in your dominant hand you place the thumb of your off-hand deep into the oropharynx grasping the base of the tongue and pulling the entire mandible anterior like a drawer. The tip of the stylet is placed in the mouth tip down and the handle is rocked/rotated into an upright position perpendicular to the plain of the patient.
Once in this position the finesse of the lighted stylet begins. Depth is controlled by lifting and lowering the handle in the aforementioned perpendicular plane. This is where the most common mistake occurs as the natural tendency is to allow the stylet to fall into the back of the oropharynx and glide right into the esophagus. You must keep the stylet up and anterior scraping against the back of the tongue. Once that anterior position is held you advance the stylet forward by slightly rocking the handle back. This forces the tip anterior and into the trachea. If the stylet is not held mid-line you may notice a slight glow off to one side or the other of the cricoid. This is caused by the tip getting placed in a pyriform sinus. To correct for this you must rock the handle away from you (withdrawing the tip from the pyriform sinus), rotate the tip slightly toward midline (careful to not over-correct), and then pull the handle toward you again advancing the tip into the trachea. If you’ve ever flown a plane, this controls very similarly to the stick of an aircraft.
When properly placed you will see a definite bright cherry-red glow in the cricoid membrane. A dull glow typically indicates an esophageal intubation. If this occurs repeat the above steps focusing on keeping the stylet anterior. The final step involves advancing the endotracheal tube into the trachea and varies by device. Once in place verify the position as you would any other intubation.
Uses and Limitations
I frequently use light wands as both a primary and rescue device. They are a great choice for trauma patients who tend to be thin, but here are some important limitations to consider prior to their use. The light can go through only so much tissue so they do not work well in obese patients or patients with significant soft tissue on the anterior surface of their neck (however after innumerable intubations with the Trachlight I can often properly intubate patients even if trans-illumination is not possible by feel alone). The light also does not pass through the tissues of darker-skinned people as well as it does those with light-skin. As the technique is a blind one you often will not know why you cannot intubate (foreign body, unusual anatomy, traumatic injury, etc). You almost invariably require a darkened setting which limits EMS use in the field and may hinder other simultaneous procedures. That being said it is a great choice in a bloody oropharynx as there is no need to see through the blood.
There are three basic choices for light wands. Laerdal’s Trachlight ($250 for handle and six stylets; $40 per stylet after) which has a reusable handle with replaceable batteries and replaceable wands that can be used approximately ten times each. Vital Signs Vital Light ($274.60) which offers a handle that is not replaceable but offers roughly 3 hours of light as well as replaceable stylets. The final version is the Aaron Medical Industries Surch-Lite ($20-40 depending on quantity) which combines the handle and light-source into a single disposable unit. Which of the three to buy comes down to frequency of use. The Laerdal Trachlight offers the most features (replaceable batteries and wands, retractable stylet, locking length adjustment) but at the highest price. The Aaron Surch-Lite is a nice option for an ED that does not intubate regularly and would use a light wand very infrequently as there is a small investment, and the Vital Light is a nice product but I’m not sure where it falls in the use category. If you perceive using a light wand occasionally I worry about the non-replaceable battery being dead so the Trachlight with its replaceable batteries is a better option. On the other hand if you would use it infrequently the Vital Light may be better for you as the entire device can be discarded after use therefore ensuring a fresh device in the rare event that you need it.
While it is the priciest of the three, the Trachlight gets my vote as the best of the bunch (by a small margin). It has staved off more than one surgeon’s knife from my patient’s neck. As my father always says, “You get what you pay for.”
Tips & Technique
>Keep stylet up and anterior, scraping against the back of the tongue.
>Once that anterior position is held, advance the stylet forward by slightly rocking the handle back (this forces the tip anterior and into the trachea).
>If the stylet is not held mid-line you may notice a slight glow off to one side or the other of the cricoid. This is caused by the tip getting placed in a pyriform sinus.