Nasotracheal intubation allows surgeons a clear approach to the oral cavity, although the incidence of nosebleed can be high. One way to minimize trauma to the nasal turbinates is to shield the tip of the endotracheal tube inside a Red Rubber Robinson catheter.
My patient was a 30-year-old healthy 5ft 11inch tall, 90 kg man scheduled at a surgery center for two head and neck procedures:
- biopsy of a 0.5 cm lesion on the back of his tongue
- bilateral functional endoscopic sinus surgery (FESS).
My surgeon requested that I start the case with a nasal endotracheal tube (NTT) for the tongue biopsy, and then switch to an oral endotracheal tube (ETT) for the FESS. “Oh, and don’t traumatize the nasal passage,” he added. “I don’t want a nosebleed.”
Reminding him that nosebleed in nasotracheal intubations can easily occur, I added that I had a lot of experience with NTTs and would do my best to avoid trauma.
Go, No Go?
Whenever planning any anesthetic, the first question should always be whether the case is safe to proceed. In aviation, this would be the “go, no go” decision. Here, the patient was healthy and the surgery was uncomplicated and appropriate for the surgery center. I needed to make sure I had an anesthetic plan and the equipment to safely accomplish what the surgeon needed for the patient.
To minimize trauma, I hoped to use a smaller diameter size 6 ETT. We did not have a 6.5 available. The first challenge was that our surgery center did not have any specific nasotracheal tubes. A nasally placed ETT must traverse a longer distance to the cords. Designated nasotracheal tubes are longer and with a specific preformed shape designed to ensure adequate depth of insertion.
Instead, I would have to use a standard adult ETT. However, the problem with a size 6 ETT is that it’s shorter than a nasotracheal tube of the same size. It’s also significantly shorter than the standard size 7-8 ETT that this tall patient would typically need to ensure the cuff is below the cricoid ring. Microlaryngoscopy tubes (MLT) exist that are small diameter but longer than standard ETTs. Unfortunately, my surgery center didn’t have any of those either. And let me add that given how rare nasal intubation is at my surgery center, it was perfectly reasonable that they did not have these two devices in stock.
I measured the 6 ETT against the outside of the patient’s neck and it appeared the 6 would be long enough — although potentially close to the cricoid ring. A cuff inflated tightly inside the cricoid ring can interrupt blood flow to the recurrent laryngeal nerve, potentially damaging it. I discussed the potential for recurrent laryngeal nerve injury with the surgeon and the patient. The surgeon stated that the biopsy should take less than 15 minutes. By ensuring minimum seal on the ETT cuff, we all felt the risk was very low.
Several minutes of soaking in hot water softened the ETT. I then inserted the tip of the ETT into the flange of a Red Rubber Robinson catheter. I lubricated the Red Rubber catheter well.
Oxymetazolone nasal spray (example: Afrin spray) acted as a nasal vasoconstrictor to maximize size of nasal passage and minimize risk of bleeding.
After induction, I gently inserted several increasing sizes of nasal pharyngeal airway to test the passage for obstruction and to pre-lubricate the passage well. I then nasally intubated using the well lubricated Red Rubber Robinson to protect the turbinates from the tip of the ETT (technique below).
Intubation was successful and atraumatic. I re-verified minimum cuff seal before the surgeon began. After the biopsy, I gently removed the NTT and replaced it with an oral size 7.5 ETT for the FESS. The patient did well, the surgeon was happy, and I was extremely relieved things had gone smoothly.
Understand Nasal Anatomy to Prevent Nasal Injury
In order to avoid complications, nasotracheal intubation must be done gently and with attention to nasal anatomy. The incidence of nosebleed ranges from 29% to 96% and can occur from soft tissue injury, lacerations and tears. Usually nosebleeds are minor and self-limiting, but occasionally can potentially be life-threatening.
To perform a nasal intubation, it’s important to remember that 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 ETT upward will be met by failure and bleeding.
The medial wall, or nasal septum, is smooth. However, it may be deviated and therefore one nasal passage may be larger than the opposite passage. The patient can often tell you which side they can breathe through the easiest. You can also pinch off each nostril in turn and feel comparative airflow.
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.
Check Past Medical History
Avoid any potential areas of bleeding and scar tissue, if possible. Ask about history of nosebleeds and nasal or oral surgery or trauma.
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.
By gently passing progressively larger, well-lubricated nasal airways you will both lubricate and test the passage for size and obstructions. If a soft nasal airway won’t pass easily, a firmer NTT won’t either.
Tips for Introducing the Nasal ETT Without Aids
Be Gentle With The Turbinates
The first place the ETT may encounter resistance is passing the turbinates. Warming the tube in hot water makes it softer and more pliable, although that also tends to straighten out any preformed curve. Coat the outside of the tube tip with water-soluble lubricant. Aim the bevel facing outward. This orientation allows it to slide along the septum and makes it less likely to tear mucosa or damage a turbinate.
If you can’t pass the tube easily, and gentle twisting of the tube doesn’t solve the problem, then switch to a smaller tube or try the other nostril. Don’t force it! One of my residents once sheared off a lower turbinate with an aggressive NTT insertion — requiring head and neck surgical intervention and a 1 unit blood transfusion.
Avoid Retropharyngeal Submucosal Dissection
The second place the tube usually hangs up is making the turn into the posterior pharynx. It’s unfortunately easy to have the tip of the ETT penetrate and burrow under the mucosa of the posterior pharyngeal wall. If this happens, you will see a bulge under the mucosa during direct laryngoscopy where the tip of the NTT should have been. The risk of bleeding and hematoma is very high in this event.
Extend the head backward to minimize the risk during insertion. When the head is in a neutral position, the tube exits the back of the nose at right angles to the posterior pharyngeal wall. It tends to dig in and can damage or tear mucosa. When you tilt the head back as you advance, the tube tip will now hit the posterior wall at an angle and tend to slide off.
Trick: Attach a Red Rubber Robinson Catheter
An even better way to avoid injury is to use a Red Rubber Robinson catheter to shield the tip , protect the turbinates, and act as a guide. Red Rubber Robinson catheters are soft, flexible catheters typically used for intermittent urinary catheterization. Insert the beveled tip of the nasotracheal tube into the flange of the red rubber catheter. It must be inserted firmly enough to remain attached while inserting the tube through the nose, but not so tight that you can’t detach it. You must remove this catheter before advancing the tube into the trachea.
Lubricate the Robinson catheter and insert it into the nares along the floor of the nose while looking inside the mouth. Grab the catheter with a Magill forceps when you see it. Advance the nasotracheal tube along the floor of the nose until its tip is in the posterior pharynx. Now detach the red rubber catheter, remove it from the mouth, and continue with the intubation by direct laryngoscopy.
Make Sure the ETT Cuff Is Below the Cricoid Ring
A nasal tube has to travel a longer distance from nares to mid-trachea than the path from the mouth. Regardless of route, always make sure your ETT cuff is below the cricoid ring to avoid recurrent laryngeal nerve injury and potential vocal cord paralysis. Inflate the cuff to minimum seal only.
Nasotracheal Intubation Complications
If a significant injury occurs:
- Remove the nasotracheal tube when safe to do so.
- Reintubate by an alternate route a appropriate.
- Watch for hemorrhage and consider hematoma formation.
- If bleeding is significant monitor Hgb. Note: an awake patient can swallow blood and the amount of bleeding may not be obvious.
- Consult with a head and neck surgeon if bleeding continues.
- Consider use of steroids and broad-spectrum antibiotics.
- Ensure follow-up for long-term complications.
- Insertion of a Foley catheter and inflation of the balloon can be used to tamponade bleeding.
Nasal intubation can cause other potential longer term complications, such as sinusitis.
Careful preparation and thoughtful attention to technique helps prevent complications. For further discussion see my reviews on avoiding anesthetic airway complications in the Anesthesiology News Annual Airway Management volumes:
Boredom Interrupted: 10 Causes of Airway Complications And How to Avoid Them
10 Rules for Approaching Difficult Intubation: Always Prepare for Failure