We perform nasal intubation, also called nasotracheal intubation, through the nose rather than the mouth. It’s a helpful technique that provides surgeons a clear approach to the oral cavity. However, to avoid complications, nasal intubation must be gently performed with attention to nasal anatomy . Here we discuss the technique of nasal intubation performed with direct laryngoscopy.
Case:
Our 70 y.o. patient needed a nasal intubation for excision of most of her badly decayed and broken teeth. Her past medical history was positive for hypertension, coronary artery disease and significant bilateral carotid stenosis.
My resident had trouble passing the nasal endotracheal tube (NTT). There was a crunching sound followed by a spectacular nosebleed. We removed the nasal tube and applied pressure. Brisk bleeding continued. Afraid that our patient might aspirate blood, we orally intubated her and called for a stat head and neck surgery consult. Intubation trauma had avulsed the left lower turbinate . After quick surgical intervention, and 1 unit of transfused blood later, we successfully extubated our patient. She remained overnight for observation. Fortunately, despite her multiple cardiovascular risk factors, she suffered no further harm.
Understand Anatomy to Prevent Nasal Injury
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 NTT upward will be met by failure and bleeding.
B. Never thread it toward the frontal sinus.
Note that the illustration is drawn without the septum to show the tube passing into the left side of the nose. The turbinates are seen on the left lateral wall of the nose behind the tube.
The medial wall, or septum, is smooth. However, one nasal passage may be larger than the opposite passage if the septum is deviated. The patient can often tell you which side they can breathe through the easiest. You can also pinch each nostril closed in turn and feel comparative airflow.
The lateral wall is not smooth, but covered by three downward-facing, scroll-shaped shelves covered by thick mucosa called turbinates (or conchae; Figure 13). You can easily see the inferior turbinate on nasal exam. These turbinates fill the nasal passage and act as potential obstructions to passing nasotracheal tubes, nasal airways and nasogastric tubes. Inserting any nasal device requires negotiating the passage between turbinates.
Check Past Medical History
Assess risks and contraindications:
- history of significant nose bleed (epistaxis)
- history of prior cleft lip/palate repair, pharyngoplasty, facial or nasal trauma, or nasal surgery
- active sinus infection
- anticoagulation or suffering from coagulopathy
Prepare the Nose For Nasal Intubation
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.
Tips for Introducing the NTT Without Aids
The NTT tip tends to hand up in two places: passing the turbinates or turning into the pharynx.
Passing the Turbinates
Warming the NTT in hot water makes it softer and more pliable. The softer tube can more easily slide past the turbinates.
Coat the outside of the tube tip with water-soluble lubricant. Aim the bevel facing outward. This orientation allows the tip to slide along the septum and makes it less likely to tear mucosa or damage a turbinate. Gently twisting the tube as you insert it can be helpful.
If it still won’t pass, don’t force it. Switch to a smaller tube or try the other nostril.
Entering the Posterior Pharynx
The second place the NTT usually hangs up is making the turn into the posterior pharynx. 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. Instead, tilt the head back as you advance. The tube tip will now hit the posterior wall at an angle and will tend to slide off (Figure 14).
B. Tilting the head into extension decreases the angle of impact and may allow it to slide downward more easily.
Combined Nasotracheal Intubation and Laryngoscopy
Visualize the larynx with your laryngoscope after the NTT enters the posterior pharynx. A curved blade provides more stability to manipulate the NTT. Once you see the larynx hold the laryngoscope blade firmly in position. Push the tube forward with your right hand into the larynx.
If the tube still by passes the cords you can have an assistant push the tube while you guide the tip of the tube into the trachea with a Magill forceps or some other instrument.
Your assistant must avoid blocking your view or bumping your arm or the laryngoscope blade. Good communication is key to the teamwork required.
Never grab the cuff itself with your forceps because you can easily rip it, leaving no way to seal off the trachea.
Grab only the tip of the tube or the area behind the cuff.
If you damage the NTT cuff, then discard that tube and use a fresh one. If you don’t have Magill forceps, you can use a bent stylet or a hook to curve the endotracheal tube anteriorly.
Direct the tube tip positioned into the laryngeal opening.
Sometimes you can feed the tube into the larynx using the Magill forceps yourself. More often you will need to ask your assistant to gently push the tube into the nose while you observe and continue to manipulate it into the trachea.
Watch Out for Complications
Make Sure the 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 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.
True nasotracheal tubes are longer than standard ETTs of the same size. There are also the microlaryngoscopy tubes that come in smaller sizes and longer lengths. If you must use a standard tube, be mindful of where your cuff sits in the trachea, as well as the pressure inside the cuff.
Nosebleed
As with the patient I described above, nosebleed is a serious risk. The incidence of nosebleed in these cases has been reported as 29% to 96%. It can occur from soft tissue injury, lacerations and tears. Usually nosebleeds are minor and self-limiting, but occasionally, as in this case, bleeding can potentially be life-threatening.
If a significant injury occurs:
- remove the nasotracheal tube when safe to do so,
- reintubate by an alternate route,
- watch for hemorrhage and consider hematoma formation,
- consult with a head and neck surgeon,
- consider use of steroids and broad-spectrum antibiotics,
- ensure follow-up for long-term complications, and
- insert a Foley catheter and inflate the balloon to tamponade bleeding
Use of Supraglottic Airway in Severe Nosebleed
Consider an emergency Laryngeal Mask Airway (LMA), ProSeal LMA, or Combitube when you can’t intubate the patient with a severe nosebleed. Since the bleeding comes from above, an LMA can help seal off the glottis and allow ventilation. An LMA, however, won’t prevent aspiration. You must suction frequently.
Monitor vital signs carefully. Remember hypertension and tachycardia can worsen hemorrhage. Make sure there is good I.V. access. In severe cases the patient may need a blood transfusion. Consider sending blood for type and cross match testing.
If bleeding continues, consider consultation from a head and neck specialist. If intubation is not possible and ventilation is inadequate consider a surgical airway.
Submucosal Dissection
Case:
Our 25-year-old male patient was scheduled for maxillofacial surgery on his mandible with nasal intubation. I was not able to pass the NTT on initial attempt. After ventilating I tried again. This time I advanced the tube with a reasonable amount of twisting force until I felt a loss of resistance and the ability to thread the tube further.
I performed direct laryngoscopy with my MAC 4 blade. I saw a grade 1 view of the larynx, however there was no ETT in sight. Puzzled, and assuming I simply had not advanced the tube far enough, I slid the tube in further. Immediately I spotted a moving bulge behind the posterior pharyngeal wall. My ETT was dissecting submucosally.
I alerted the surgeon and slowly removed the nasal ETT, expecting a significant nosebleed to follow. Thankfully it did not. We canceled the case . The patient recovered from anesthesia quickly and didn’t suffer any bleeding or infection from the mishap.
Managing A Submucosal Dissection
Submucosal dissection can occur if the NTT tip tears and slides underneath the posterior pharyngeal mucosa.
Signs of a submucosal dissection include:
- No tube visible in posterior pharynx once the tube has turned the corner
- The absence of breath sounds through the tube
- The presence of a bulge behind the tonsillar pillars
- Complaints of pain in the back of the throat in an awake patient
- Significant resistance as you advance the tube
When a nasotracheal tube is submucosal, remove it carefully and prepare for a heavy nosebleed. Consider postponing elective surgery because of the risk of retropharyngeal hematoma and abscess formation. If you must perform nasal intubation, then control bleeding, and carefully try the other side. Watch for airway obstruction due to potential swelling.
In summary, nasal intubation using direct laryngoscopy is an important skill. However, it must be performed gently and with close attention to anatomy to avid complications. Teamwork and communication are also essential to success.
My previous review articles discuss many emergencies/complications and how to avoid them. Check out:
Boredom Interrupted: 10 Causes of Airway Complications and How To Avoid Them
10 Rules for Approaching Difficult Intubation
10 Common Pediatric Airway problems — And Their Solutions
May the Force Be With You
Christine E Whitten MD, author
Anyone Can Intubate: A Step By Step Guide
and
Pediatric Airway Management: A Step By Step Guide
