Video laryngoscopy, with a device such as the Glidescope, makes oral intubation of the patient with a difficult airway much easier. However, using video laryngoscopy for nasal intubation can be technically challenging. Use of a nasal airway and a pediatric bougie can greatly simplify this task.
Nasotracheal intubation is a helpful technique that allows surgeons a clear approach to the oral cavity. But it must be done gently and with attention to nasal anatomy to avoid complications.
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Routine nasotracheal intubation typically uses direct laryngoscopy to visualize the tip of the nasotracheal tube (NTT) in the posterior pharynx. The intubator then uses a Magill forceps to guide the tip of NTT into the trachea.
However, nasal intubation can be difficult when intubating using a video laryngoscopy device like the GlideScope for two reasons:
- You are no longer working with a direct line of sight, but a curved passage.
- There may not be enough room to maneuver the GlideScope, the ETT and the Magill forceps.
You can use a nasal airway and a pediatric bougie to make this technique a lot easier. Let’s discuss how to overcome these problems.
Remember Nasal Anatomy
The passage from the nares to the posterior opening into the pharynx is horizontal. It runs parallel to the hard palate that forms the floor of the nose. It’s a novice mistake to think that the passageway follows the septum upward. Attempts to introduce the nasal NTT upward will be met by failure and nosebleed.
The medial wall, or septum, is smooth. However, the lateral wall is not smooth, but is covered by three downward-facing, scroll-shaped shelves covered by thick mucosa called turbinates. The inferior turbinate is easily seen on nasal exam. These turbinates fill the nasal passage and act as potential obstructions to passing nasotracheal tubes, nasal airways and nasogastric tubes. Inserting a nasotracheal tube, or any nasal device, requires negotiating the passage between turbinates.
Prepare the Nose
Maximize the size of the nasal passage and minimize the risk for bleeding by using a nasal vasoconstrictor such as oxymetazolone or phenylephrine. If using cocaine, monitor hemodynamic effects.
Insert A Nasal Airway
After vasodilating the nose, insert a nasal airway. You need to use a nasal airway for this technique to protect the turbinates and posterior pharynx from trauma from the bougie tip. Although bougies are flexible, they are rigid enough to both guide endotracheal tubes and tear mucosa.
By gently passing progressively larger, well-lubricated nasal airways you will both lubricate and test the passage for size and obstructions.
Perform Glidescope Laryngoscopy
Visualize the larynx with your GlideScope. Visualizing the posterior pharynx first, before inserting the bougie, minimizes the risk that the bougie will traumatize area during insertion because you will be watching it enter.
Once you have a good view of the larynx on your viewscreen, stabilize your left hand holding the video laryngoscope. You need to prevent movement and protect the teeth as your right hand manipulates bougie, nasal airway, and finally NTT.
To review use of the GlideScope see:
Advance The Pediatric Bougie Through the Nasal Airway
Either you, or your assistant ,should then advance a pediatric bougie through the nasal airway and into the pharynx while you are watching with the GlideScope. The pediatric bougie is smaller bore and more flexible than an adult bougie. It can therefore easily make the turn into the posterior pharynx.
As soon as the bougie enters the pharynx, you will usually be able to manipulate it into the glottis. Advance it halfway down the trachea and stop. Be gentle. Do NOT advance the bougie all the way to the carina. Tracheal perforation and pneumothorax is possible.
Nasal Intubation Using Video Laryngoscopy
With the help of your assistant, remove the nasal airway, being careful to leave the bougie undisturbed. Thread your well lubricated nasotracheal tube over the bougie and through the nose. The NTT will follow the path of the bougie. Be gentle as you pass the turbinates. Watch the NTT enter the glottis. If the NTT tip hangs up on the vocal cords, gently rotate it to slip between them. Once intubated, remove the bougie.
If holding the GlideScope is getting in the way, you can temporarily remove it once the bougie is in place. Pass the NTT over the bougie and into the posterior pharynx. Stop, reinsert the GlideScope to watch as the NTT enters the larynx. Slowly back the bougie out of the trachea and the NTT. Again, be gentle to avoid potential tracheal injury.
There is a very real tendency to advance the bougie as you advance the endotracheal tube. Keep the bougie fixed in position.
Even though you just watched the tube enter the trachea, always verify tracheal placement.
Make Sure the Nasal ETT Cuff Is Below the Cricoid Ring
A nasal tube must travel a longer distance from nares to mid-trachea than the path from the mouth. We often use smaller gauge tubes for nasal intubation in attempt to minimize trauma and ensure that we have chosen a tube that will pass through the nose. The problem is those smaller gauge tubes are often significantly shorter than their larger counterparts. Too short a tube can place the cuff inside or above the cricoid ring.
Intubation-related recurrent laryngeal nerve injuries most commonly occur when the cuff sits partially inside the rigid cricoid cartilage, causing transient, possibly permanent, vocal cord paralysis. A cuff inside the cricoid ring can easily occur with nasal intubation.
Using video laryngoscopy for nasal intubation is helpful when the patient is difficult to intubate or has an otherwise challenging airway. Passing a pediatric bougie through a nasal airway to use as a guide can make it much easier, and less traumatic.