Nasal intubation

Nasal intubation is an approach to endotracheal intubation often used to increase intraoral exposure during head & neck surgery.

Indications

• Transoral robotic surgery
• Maxillofacial surgery
• Dental surgery
• Restricted mouth opening
• Cervical spine instability
• Lower facial trauma
• Structural abnormalities that preclude oral intubation

Contraindications

• Severe bleeding diathesis
• Anticoagulation
• Basilar skull fractures
  • Advancing a nasal tube in a patient with a basilar skull fracture risks penetration into the brain.

Patient evaluation

A history of nasal septal deviation, polyps, and prior nasal surgery should be elicited. Patients with previous reconstructive orofacial surgery or nasal stenosis may have nasal anatomy that does not permit passage of an nasal endotracheal tube. In these cases, preoperative endoscopic airway examination (PEAE) and craniofacial CT imaging is helpful to determine feasibility of nasal intubation.

Preparation of Nasal Mucosa

Topical anesthesia and vasoconstriction

Vasoconstriction of the nasal mucosa may be achieved using oxymetazoline 0.05%. If topical anesthesia is also desirable, lidocaine 3-4% (with phenylephrine 0.25-1%) or cocaine 4-10% may also be used. Prepare for any potential hemodynamic effects from systemic absorption of the drugs and/or additives used.

Consider, alternatively mixing small but equal amounts of 0.2mg glycopyrrolate, with 100mcg /cc phenylephrine, which should balance out heart rate perturbations during induction. Spray 2-3 cc of each onto 4X4, and add lubricant.

Mechanical dilation

Serial mechanical dilation of the nares with nasal trumpets prior to nasal intubation is controversial and in some studies has been associated with higher rates of trauma and hemorrhage to friable nasal mucosa. Robertazzi aiways size 28-34 usually sufficient.

Consider preparing a Red Rubber Urethral Catheter. Size 12Fr is ideal in most cases. Above this size, the catheter is too stiff and can cause trauma. Smaller sizes are too soft and cannot be easily directed. Lubricate the nasal airways and catheter, with 2-3 drops of vasoconstricting agent.

Selection of Endotracheal Tube

Tubes placed via the nasotracheal route must be of smaller diameter and increased length compared to tubes used for orotracheal intubation.

• Nasal RAE tubes have a preformed bend at a set depth depending on the internal diameter of the tube
  • Must be sized appropriately by comparing them to the patient's profile in order to ensure that the cuff will lie at the appropriate depth
  • Most patients require a size 7.0 mm internal diameter nasal RAE or larger
• Microlaryngeal tubes may be used if a smaller diameter is desirable
  • Typically 5.0 mm and 6.0 mm internal diameter are sufficiently long to be used for nasotracheal intubation

Prepare Nasal RAE by leaving in a container of warm saline. Have half a size up and below available and similarly prepared. Traditionally this is necessary with clear plastic RAE's due to their stiffness. Consider using softer tube to minimize pharyngeal trauma (such as Smiths Medical Portex), but and more difficult to direct /manipulate, and require McGill Forceps.

After dilating Nares sequentially with Nasal Airways, insert Red Rubber Urethral catheter into nares, with RAE ET tube attached to trailing end. Under DL, carefully pull out leading edge of red catheter from pharynx, and detach, looking away. Proceed under DL to intubate with or without McGill. May need to rotate ET tube to direct the leading edge through the vocal chords.

Alternatively, if patient has narrow mouth opening, can attempt placement utilizing Glidescope. After placing RAE ETT in nare, perform laryngoscopy using Glidescope. Once vocal cord is in view, minimalize the upward force of the Glidescope blade such that the glottis and vocal cords are sitting in the lowest position on the screen and centered. Advance RAE ETT until visualized on Glidescope screen. Line up the tip of the nasal RAE with glottic opening and advance. If the glottis appears higher than tip of ETT, inflate balloon until tip is aligned with glottis and advance.

Complications

Epistaxis

• Most common complication of nasal intubation epistaxis from nasal trauma
• Causes include
  • Inadequate vasoconstriction
  • Larger diameter endotracheal tubes
  • Excessive force
  • Repeated insertion attempts.
• Softening the endotracheal tube in hot water may reduce risk
• If bleeding occurs, intubation should be completed quickly if possible.
  • If rapid intubation is not possible, the endotracheal tube should be withdrawn into the post-nasal space and the balloon inflated to tamponade bleeding

Alar necrosis

• Occurs due to pressure from the nasal tube
• May occur quickly
  • Has been reported in nasal intubations of even short duration.
• Prevented by securing the tube such that pressure is avoided on the nasal ala

Other complications

Rarely, more serious complications occur such as avulsion of turbinates or nasal polyps, posterior pharyngeal wall laceration, dissection, and sinusitis.