Airway, Nasopharyngeal

Article Author:
Zaza Atanelov
Article Editor:
Sarah Rebstock
Updated:
7/15/2018 12:48:07 PM
PubMed Link:
Airway, Nasopharyngeal

Introduction

Basic airway management in both the pediatric and adult populations includes assessing and managing airway patency, oxygen delivery, and ventilation. All efforts should be taken to maintain a patient’s airway via non-invasive methodology unless indications for invasive airway management are apparent. Non-invasive airway supplementation includes passive oxygenation (nasal cannula, non-rebreather, among others), bag-valve-mask (BVM), non-invasive positive pressure ventilation (BVM with positive-pressure valve, CPAP, BIPAP), and supraglottic airways (King Tube, LMA. among others). Invasive airway management involves establishing a secure airway and placing patients on a ventilator via intubation (nasal or endotracheal), needle jet ventilation (in pediatric patients younger than 8 years old, cricothyroidotomy in pediatric patients older than 8 years old, and adults), and tracheostomy.

Proper airway management begins by looking at the patient visually for trauma, obesity, cervical collar, macroglossia, among other factors to determine the type of airway approach best suited for each patient. Most important is positioning via the head tilt-chin lift maneuver, which involves extending the patient’s neck by putting one hand on the forehead and the other hand on the neck to allow for the extension of the head in relation to the neck. This maneuver puts the patient into sniffing position, with the nose pointed upward and forward. Then a chin lift can be performed by taking the hand from underneath the neck to underneath the chin (mandible) and lifting the mandible until the teeth barely touch. Another airway positioning method involves the jaw thrust maneuver, which is safer in potential cervical spinal cord injury patients. This method involves maintaining the spine in a neutral position and grabbing the sides of the angle of the mandible and lifting it forward to lift the jaw and open the airway.

There are some differences between the pediatric and adult populations. For example, the large occiput of the pre-pubescent pediatric patient can lead to too much flexion of the neck and can cause tracheal obstruction. This is addressed by utilizing the head tilt-chin lift maneuver, but care must be taken to avoid overextension in the pediatric population as it can cause airway obstruction due to a weak trachea in the pediatric patient. However, the head tilt-chin lift may not be adequate to maintain a patent airway, and the jaw thrust maneuver may need to be employed to prevent the pediatric, large, floppy tongue from obstructing the airway.

Once properly positioned, the rescuer has the best shot at delivering effective breaths either via mouth to mouth or BVM.

If there is continued difficulty at delivering breaths, then airway adjuncts like an oral pharyngeal airway (OPA) device or nasopharyngeal airway (NPA) can be useful for maintaining a patent airway to allow delivery of breaths in an unresponsive patient. NPA devices can be useful at maintaining the airway in an awake patient as well, which is beneficial if intubation is not the goal, intubation needs to be delayed, or an awake intubation is necessary.

NPA devices are plastic hollow or soft rubber tubes that a healthcare provider can utilize to help with patient oxygenation and ventilation when the patient is difficult to oxygenate or ventilate via BVM, for example. NPAs are passed into the nose and pass through to the posterior pharynx. NPAs do not cause patients to gag and are, therefore, the best airway adjunct route in an awake patient and the better choice in a semiconscious patient that may not tolerate an OPA due to the gag reflex. NPAs are also helpful when a patient's mouth is difficult to open, for example, if there are angioedema, trismus, or other factors.

While NPAs are airway adjuncts for difficult patient ventilation and oxygenation, they only act as a bridge to either an eventually stabilized patient that is breathing without aid or a patient that requires a secure airway via endotracheal or nasotracheal (NT) intubation.

The NT route for intubation was the preferred route among critical care and emergency physicians up until several decades ago. However, today, the majority of clinicians prefer the endotracheal route for intubation as it has been shown to have better results and fewer complications. Some of the complications of NT intubation include sinusitis, nasal structure destruction due to localized pressure and decreased perfusion of nasal cartilage, and local abscesses. Furthermore, NT intubation requires narrow tubes making pulmonary toilet very difficult due to the increased airway resistance.

However, there are clear advantages to NT intubation. NT intubation can be performed in the sitting position, which is valuable, especially in the pre-hospital setting when needing to intubate a patient in acutely decompensated heart failure that cannot lay flat. Other advantages include the patient’s inability to bite or manipulate the tube, better patient tolerance, decrease salivation, and better access to patient oral care. In addition, the NT tube is much more stable as it has the entire nasal tract holding it in place versus the endotracheal tube that flops out the mouth and can easily dislodge or become right mainstemmed.

NT intubation can be performed blind or with a flexible bronchoscope. Blind NT intubation is difficult and requires expertise and skill. However, when indicated, can be a very useful skill both in the prehospital and hospital setting. Blind NT intubation decreases the need for neck movement and mouth opening, but can only be done in the awake and ventilating patient. NT intubation via a flexible bronchoscope also requires lots of expertise and skill, and it is useless if there is blood, vomitus, or fluid that will obscure the bronchoscopes camera.

Anatomy

The nose directly communicates with the multiple sinuses of the face, brain via cribriform plate, and the pharynx, esophagus, and trachea via the nasopharynx. The nose is separated into 2 nares separated by a mostly cartilaginous nasal septum. Each naris is made up of 2 pathways, the lower and upper pathway. The lower pathway lies along the nasal floor underneath the inferior turbinate, and the upper pathway lies above the inferior turbinate and below the middle turbinate. The middle turbinate is a vascular structure connected with the cribriform plate, so care has to be taken not to cause damage to the middle turbinate. Therefore, the lower pathway is the ideal pathway to take when placing an NPA or performing an NT intubation. Care must be taken to avoid placing an NPA or NT tube cephalad, but rather aimed toward the occiput and nasopharynx caudally along the nasal floor.

The nasopharynx leads into the oropharynx and then into the hypopharynx. The hypopharynx precedes the entrance to the trachea and esophagus; it is also where the larynx lies. When looking at the larynx, from the top down, there is the vallecula, epiglottis, vocal folds, and vocal cords. The vocal cords open into the trachea.

Indications

Indications for when the nasal route is first and sometimes the only route for intubation, without establishing a surgical airway are numerous. In an emergency circumstance, the healthcare provider should consider NT intubation when the patient presents with a strong gag reflex, limited mouth opening, macroglossia, cervical spine instability, severe cervical kyphosis, severe arthritis, intraoral masses, structural abnormalities, trismus, or angioedema. In the pre-operative setting, nasopharyngeal intubation should be considered in patients requiring maxillofacial surgery or dental procedures.

Furthermore, NT intubation is better tolerated than endotracheal intubation in the awake patient, and should, therefore, be considered when there is a need for awake intubation. The circumstance where this is beneficial is when the patient has persistently low oxygen saturation in spite of preoxygenation efforts and is also an anticipated difficult airway.

The most common patient population where this is the case is among patients with congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), and asthma exacerbations. Furthermore, the CHF patient is in respiratory distress and cannot tolerate lying in the supine position. An NT intubation can be performed while the patient is awake in the sitting up position. Therefore, patient comfort increases and the risk of losing the airway is greatly reduced if the CHF, COPD, asthma patient is paralyzed and sedated and there is difficulty oxygenating, ventilating, or securing an airway. The provider should allow the CHF, COPD, and asthma exacerbation patients to maintain their respiratory drive while the airway is secured.

Contraindications

Blind NT intubations should be avoided entirely in the very young pediatric population as the airway is more anterior and cephalic making blind passage of the tube almost impossible. Blind NT intubation should also be avoided in patients with expanding neck hematomas, oropharyngeal trauma, and in patients with apnea (no breaths to guide blind intubation).

Absolute contraindications for NPA and NT intubation, blind and not, include signs of basilar skull fractures, facial trauma, and disruption of the midface, nasopharynx or roof of the mouth.

Relative contraindications include suspected epiglottitis, coagulopathic patients (including those taking anti-coagulants) due to the risk of hemorrhage, large nasal polyps, and recent nasal surgery.

Equipment

When placing an NPA, the healthcare provider should be knowledgeable regarding the sizing of the NPA. Adult sizes range from 6 to 9 cm. Sizes 6 to 7 cm should be considered in the small adult, 7 to 8 cm in the medium size adult and 8 to 9 cm in the large adult. If the healthcare provider is unsure of which size to use, and there is time to assess which size to use, then the provider can place the NPA at the nasal opening and orient it down toward the angle of the mandible. If the NPA goes past the mandible, then it is too long, and if it does not reach the mandible, it is too short.

Equipment for blind NT intubation is the same as for flexible bronchoscope NT intubation beside the bronchoscope. There should be NT tubes in several sizes, lidocaine jelly or lubricant, topical vasoconstrictor (oxymetazoline 0.05%, phenylephrine 0.5%, cocaine), aerosolized 2% to 4% lidocaine, NPAs, syringe to inflate cuff, suction tubing, suction yanker, BVM, nasal cannula for apneic oxygenation if sedating, backup airway devices (LMA, glideslope, bougie, surgical airway, among others).

Personnel

The personnel varies in pre-hospital and hospital settings, however, if possible, there should be additional healthcare providers to the one performing the procedure. In the pre-hospital setting, having someone to hand supplies, inflate the balloon, and perform any other needed tasks can be very helpful. In the hospital setting, a nurse may be needed to attach the patient to the monitor, set up sedative or paralytic medications, administer medications, and perform other tasks. Furthermore, most hospitals now have respiratory therapists that will help secure the ET tube, place the patient on a ventilator, and help monitor the patient’s respiratory status post intubation. In the emergency department setting where NT intubation is no longer regularly performed, having an anesthesiologist or otorhinolaryngologist (ENT) may be necessary and helpful to the emergency medical provider.

Preparation

Preparation for insertion of an NPA involves 2 steps. First, the healthcare provider gets the correct size NPA, and second, the provider coats the NPA with lubricant, anesthetic jelly, or any water-soluble lubricant.

In the ideal setting preparation for NT intubation can include all of the below-mentioned steps, but if the procedure if needed to be done immediately, the healthcare provider may be unable to prepare anything and may have to blindly place the NT tube when that is the indicated route of securing the airway.

Preparatory steps, not necessarily in the below order, include:

  1. Positioning the patient in the sniffing position, attaching the patient to the monitor, pulse oximetry, blood pressure monitor and cardiac monitor. If available, set up end-tidal carbon dioxide monitor (capnography)
  2. Placing 2 peripheral intravenous (IV) accesses and starting 1 liter of crystalloid fluid (if the patient is not fluid overloaded or at risk of overload)
  3. Preoxygenation via nasal cannula, non-rebreather, BVM, BIPAP increases the oxygen reserve and the time to desaturation after a sedative and/or paralytic medications have been given.
  4. Having a BVM ready bedside
  5. Turning on wall suction, setting up the suction tubing and a yanker
  6. Having a respiratory therapist or other personnel prepared with a ventilator
  7. Preparing sedative and paralytic medications if plan on sedating and/or paralyzing
  8. Having a CO2 detector, EtCO2
  9. Setting up the backup airway
  10. Setting aside 6 to 7.5 cm NT tubes and checking the cuff of the tubes for an air leak
  11. If using flexible bronchoscopy, having the bronchoscope turned on and placed bedside
  12. Placing the NT tube in warm sterile saline to allow the tube to soften and allow for a smoother insertion; this can decrease the risk for trauma to the nasal passageways.
  13. Assessing for the more patent nostril, which can be done by asking the patient to hold one nostril and take in a deep breath, identifying which naris allows for more air movement. It can also be assessed by placing an NPA and judging which naris allows for easier insertion. If the provider will be utilizing a flexible bronchoscopy, then the scope can be used to visualize which nostril is more patent.
  14. Lubricating the tube and bronchoscope with lubricant or lidocaine jelly/ointment. Care should be used to avoid smudging the camera of the bronchoscope.
  15. Spraying a topical vasoconstrictor in bilateral nares to reduce bleeding risk
  16. Placing an NPA coated with lidocaine jelly/ointment to provide anesthesia and lubrication
  17.  Spraying aerosolized lidocaine in the oropharynx
  18. Performing serial dilations of the bilateral nares or more patent nares with increasing larger diameter NPAs coated with lidocaine or lubricant

Technique

Insertion of an NPA is straightforward and involves the healthcare provider inserting the NPA into the nares with the concave side facing down to allow for insertion into the posterior pharynx behind the tongue. If there is resistance, the NPA can be rotated, which should allow the tube to fit snugly into the nares. Do not aim the NPA cephalad, but instead aim it straight back toward the occiput and along the nasal floor via the lower pathway of the naris.

In blind NT intubation, the healthcare provider begins by placing the tube into the chosen naris similar to the NPA with the concave side facing down and aim toward the occiput. The bevel of the tube should face the lateral wall of the nasal passage, and the tube should be slowly advanced toward the occiput and nasopharynx. At approximately 6 to 7 cm in the tube will pass through the nasal passageway and begin its acute drop into the nasopharynx. At that point, the provider should feel significantly less resistance and the patient, if awake, will be very uncomfortable, as passing the tube into the nasopharynx is the most painful part of the procedure. Resistance should be overcome with gentle, slowly rotating and twisting motions until the tube passes through.

Once in the nasopharynx, the tube will easily advance into the oropharynx, hypopharynx, and larynx to approach the vocal cords. At this point, the provider should asses for breath sounds and fogging of the tube. The tube can be slowly advanced until maximal breath sounds are appreciated. The tube is then advanced with a patient’s inspiratory effort allowing the suction of inspiration to increase the likelihood of the tube going into the trachea. Cough/stridor during this advancement indicates placement into the trachea; absence of cough/strider may indicate esophageal placement.

The approximate distance when the healthcare provider should slow advancement and anticipate vocal cords is 16 to 17 cm. If the tube has moved passed this distance and the provider is still awaiting tube fogging and increased breath sounds, the provider should consider that the tube may be in the esophagus. If the patient reflexively swallowed the tube into the esophagus, the provider can pull the tube back and have the patient stick his/her tongue out to prevent swallowing. However, the tube may also be in the arytenoids, piriform sinus, or anterior to the epiglottis in the vallecula if there is difficulty passing it past 15 to 16 cm. Providers may find that when coming in from the right nares that the tube may be stuck at the right arytenoids and vocal cords. Palpation of the soft tissues during the passage of the tube can be helpful in finding the tube. Before attempts, pull the tube back slightly, approximately 1 to 2 cm, change the patient’s head position if it is stuck at the vallecula or rotate the tube 90-degrees counterclockwise if the tube is stuck in the arytenoids or vocal cords and slowly push the tube back.

If repeat attempts continue to result in esophageal intubation, then the provider can withdraw 1 to 2 cm from where breath sounds are lost, and esophageal intubation assumed. Then the provider should improve head positioning with further extension and/or inflate the cuff with 15 ml of air. Inflating the cuff will position the tube tip toward the trachea. The tube then can be advanced 1 to 2 cm, and if breath sounds are still appreciated then the cuff can be deflated, and the tube advanced into the trachea.

Once in the trachea, there should no longer be vocalizations from the patient as the vocal cord cannot move against the tube. The provider should hear breath sounds and see the fogging of the tube. Furthermore, if using EtCO2 or a CO2 detector, you will see an appropriate EtCO2 and waveform and appropriate color change of the CO2 detector. The provider should advance the tube about 26 cm for females and 28 cm for males. Then the provider should listen for equal, bilateral, breath sounds and get a chest x-ray to confirm placement above the carina and past the clavicles.

The above-detailed explanation about blind NT intubation covers a majority of the knowledge and technique for NT intubation. Following is an explanation the nuances of doing an NT intubation with a flexible bronchoscope. While blind NT intubation can sometimes be based more on luck than skill, NT intubation with a flexible bronchoscope is a skilled procedure that requires familiarity with the equipment, as some healthcare providers, like emergency medical providers, rarely use bronchoscopy.

When using a flexible bronchoscope, one can either load the NT tube onto the bronchoscope or first pass the tube to about 15 cm and then insert the bronchoscope to locate the trachea and successfully intubate.

When placing the tube onto the bronchoscope, the healthcare provider should slowly advance the scope through the most favorable nasal route, preferably beneath the inferior turbinate and into the nasopharynx, which decreases the risk of epistaxis and damage of nasal turbinates.

When placing tube prior to using bronchoscopy, one should place the bevel of the NT tube toward the lateral wall of the nasal passage and use the same technique to placing a blind NT tube and NPA with care to pass the tube beneath the inferior turbinate, toward the occiput and caudally toward the nasopharynx. The tube should be placed at about 15 cm +/- 1 cm, and then the bronchoscope should be inserted into the tube where the larynx should be seen. If performing an awake intubation 2 mL of 2% to 4%, aerosolized lidocaine can be sprayed onto the vocal cords before NT tube passage. The bronchoscope is then advanced first, to the level of the carina, and the NT tube can be advanced. Just like with blind intubation, one should expect the NT tube to be at about 26 cm with females and 28 cm with males.

Special consideration should be taken when using the flexible bronchoscope to perform an NT intubation to suction the oropharynx before and possibly during the procedure to minimize obstruction of the lens. Secretions can also be cleared by utilizing pressurized oxygen through the bronchoscope channel.

Complications

There will always be complications with any intervention or procedure; however, if done correctly and if contraindications are appropriately avoided, then there should be few complications with both NPA insertion and NT intubation. However, NT intubation is a much more complex procedure and comes with a significantly higher rate of complications.

NPA placement is absolutely contraindicated when the patient has a basilar skull fracture. Therefore, if placed in a patient with a basilar skull fracture you risk the NPA going upward toward the brain and causing central nervous system (CNS) damage. There are very few cases of that ever occurring, but the fact that it could happen should make one wary of placing an NPA in a head trauma patient. Other, more common complications of NPA insertion include gastric distention from placing an NPA too long for the patient and injury to the nasal mucosa. When the NPA is too long for the patient, it can create a direct route of ventilation of the stomach, cause gastric distention, increase vomiting risk, and decrease oxygenation and ventilation of the lungs.

Complications with nasotracheal intubation include epistaxis, turbinate fracture, intracranial placement through a basilar skull fracture, and retropharyngeal dissection or laceration. After successful nasotracheal intubation patients may develop sinusitis, which can lead to sepsis. Blind placement increases the risk for esophageal placement and retropharyngeal laceration, but otherwise, blind and bronchoscopic placement has similar complications.

Clinical Significance

There are many reasons why an NPA would be utilized and/or why nasal intubation can be beneficial and sometimes the only route for intubation. An NPA should be part of everyone healthcare provider’s arsenal for basic airway management. Nasotracheal intubation, although rarely utilized, should not be placed by the wayside and should be a skill maintained by any healthcare provider who normally intubates patients to maintain their airway.