Nasopharyngeal Cannula: What is it? Indications, Contraindications, Placement and Use in Children

It is a device that consists of a bougie or filiform cannula that is designed for use in probing or dilating the Eustachian tube.

This type of generic device includes Eustachian catheters.

A nasopharyngeal cannula is located in the nasopharyngeal space with low oxygen flow, which sends an oxygen reservoir to the nasopharyngeal area.

When used at low flow rates, gastric distention does not occur if the cannula is positioned correctly. However, the baby must also have a free draining nasogastric tube.

The nasopharyngeal oxygen cannula should be repositioned immediately if gastric distention is observed. It should be used in patients aged 0-2 years and a nasopharyngeal cannula size FG8.

Position of the nasopharyngeal cannula: insert it through the nose to a distance equal to that of the nose to the tragus of the ear. The cannula will be just below the soft palate.

Compressed oxygen from the wall supply is very dry, and long-term administration can damage the nasopharyngeal mucosa.


Heated humidification is used with a Fisher and Paykel humidifier and an RT229 circuit. The humidifier and course should be changed weekly to reduce bacterial infection.

The cannulas are often blocked with mucus. The cannula should be removed and cleaned twice a day if the patient suddenly desaturates.

Nasopharyngeal route

In medicine, a nasopharyngeal airway, also known as NPA, nasal trumpet (due to its flared end), or nasal hose, is an attached airway; it is a tube inserted into the nasal passage to ensure an open airway.

When a patient is rendered unconscious, the jaw muscles relax and can allow the tongue to slide back and obstruct the airway.

This makes airway management necessary, and a nasopharyngeal route is one of the tools available.

The purpose of the flared end is to prevent the device from getting lost inside the patient’s nose.

A safe and comfortable alternative to an oxygen mask

Nasopharyngeal oxygen therapy (NPO) is an emerging alternative to conventional oxygen mask delivery.

It deserves consideration for treating hypoxemia when mask therapy is impractical or when patient intolerance or non-compliance regularly interrupts treatment.

The effectiveness of the nasopharyngeal oxygen pathway has been validated in pediatric and post-anesthesia intensive care units (PICUs), but use in the adult intensive care unit remains minimal.

Recent research in the adult intensive care unit has shown that the nasopharyngeal route is as effective as oxygen mask delivery in relieving mild to moderate hypoxemia and is significantly more comfortable for patients.

Therefore, nasopharyngeal oxygen, delivered through a fine cannula advanced into the nasopharynx, should be considered when face masks (MF) or nasal prongs (PN) are impractical or poorly tolerated due to their efficacy and greater comfort in patients in whom non-invasive oxygen therapy is indicated.

There are also implications for resource and cost utilization.


As with other cannulas, nasopharyngeal airways are measured using the French catheter scale, but sizes are generally quoted in millimeters.

Typical sizes include : 6.5mm / 28FR, 7.0mm / 30FR, 7.5mm / 32FR, 8.0mm / 34FR, and 8.5mm / 36FR.

Indications and contraindications

These devices are used by emergency care professionals, such as EMTs and paramedics, in situations where an artificial form of airway maintenance is needed. Still, tracheal intubation is impossible, inadvisable, or out of reach. Of the professional’s practice.

The nasopharyngeal airway is often used in conscious patients where an oropharyngeal airway could trigger the gag reflex.


The correct size airway is chosen by measuring the device in the patient: the instrument should reach from the patient’s nostril to the earlobe or angle of the jaw.

The outside of the tube is lubricated with a water-based lubricant to make it easier to enter the nose. The device is inserted until the flared end rests against the nostril.

Nasopharyngeal oxygen cannula placement

Placement of a nasal oxygen insufflation cannula is a quick and easy means of providing supplemental oxygen to the hypoxic patient.

Nasal oxygen insufflation cannulas are well tolerated, require minimal equipment, and are easy to maintain.

It should not be considered in patients with laryngeal obstruction, nasal or facial trauma, nasal obstruction (foreign bodies or massive lesions, including fungal infections or neoplasms), or bleeding disorders.

Furthermore, since sneezing sometimes occurs during placement, its use is relatively contraindicated in patients at risk of increased intracranial pressure, including intracranial neoplasia.


Argyle feeding tube or red rubber cannula, surgical staples or 3-0 nylon suture, 2% lidocaine or 0.5% proparacaine hydrochloride, sterile lubricant, permanent marker, 1 ml syringe case, extension tube flexible, oxygen source, humidification bubble, rigid Elizabethan collar.

Preparation and procedure

The patient’s nostril should be anesthetized with 0.5-1 ml of diluted 2% lidocaine or several drops of 0.5% proparacaine, tilting the head back to ensure the nasal mucosa lining with the topical anesthetic.

In the case of nasal oxygen cannula placement, the tip of the tube is placed on the lateral ridge of the eye, and the area adjacent to the end of the nose is marked with a permanent marker.

In the case of nasopharyngeal oxygen cannula placement, the tip of the tube is measured from the ramus of the jaw to the end of the nose and marked accordingly.

The tip of the tube is lubricated, and the line is held just to the side and in front of the nostril, as close to the nostril as possible.

The patient’s muzzle is supported with the other hand to facilitate positioning. The tube is directed ventrally and medially at the mark level on the line.

In the case of nasopharyngeal cannula placement, the nostril is pushed dorsally, and the lateral portion of the nostril is moved medially at the same time, directing the cannula into the ventral nasal passage.

Once the tube is in place, it is secured with surgical staples or nylon suture material, avoiding whiskers.

Usually, we secure it over the upper part of the nasal plane between the eyes, up to the top of the head, and immediately put on a rigid Elizabethan collar.

Oxygen flow rates of 50-100 ml/kg/minute are generally well tolerated as long as the oxygen source is humidified to prevent drying of the nasal mucosa and airways.

Topical anesthesia (0.5% proparacaine) can be instilled as needed for patient comfort.

Nasopharyngeal oxygen in children

The World Health Organization recommends nasopharyngeal tubes as safe and efficient for administering oxygen to infants. However, little is known about the mechanisms of oxygenation enhancement.

Hypoxia caused by pneumonia or bronchiolitis is a common cause of death in children in developing countries.

Oxygen is costly in developing countries, and the limited supplies available must be used as efficiently as possible.

Administration of oxygen through an 8 FG nasopharyngeal cannula inserted into the nose at a depth equal to the distance from the side of the nose to the front of the ear so that the tip of the cannula was visible in the pharynx under the soft palate.

A 150 ml/kg/min flow rate gives an inspired oxygen concentration of approximately 50% in children under two years of age.

Thus, newborns with pneumonia can generally be treated with 0.5 L / min and infants up to 12 months with 1.0 L / min of nasopharyngeal oxygen.


After heart surgery, nine spontaneously breathing newborns (median age 13 months, range ten days to 20 months) were investigated.

All patients had normal pulmonary blood flow at the study time (Qp: Qs = 1: 1).

During the study, oxygen (oxygen fraction 1.0) was administered via a size 8F nasopharyngeal cannula inserted into the nasopharynx (tip visible under the soft palate).

Pulmonary mechanics were analyzed using a single-compartment model of the respiratory system.

  • Esophageal pressure (Pes) at the end of expiration.
  • Dynamic lung compliance (CL) and resistance (RL).
  • Minute ventilation.

Carbon dioxide partial pressure (PaCO2) and oxygen partial pressure (PaO2) was measured initially without the nasopharyngeal cannula or oxygen and with oxygen flows of 0.5 L / min, 1.0 L / min, and 2.0 L / min.

All flows generated significant increases in producing a positive end-expiratory pressure. The difference in means has a positive end-expiratory pressure (SD, paired t-test vs. baseline):

  • 1.6 cm H2O (1.4, P = 0.008) with 0.5 L / min of oxygen; 2.8 cm H2O (2.7, P = 0.014) with 1.0 l / min of oxygen; and 4.0 cm H2O (2.9, P = 0.004) with 2.0 l / min of oxygen.

There was a significant correlation between all nasopharyngeal flows (in ml/kg per minute) and what was generated produced a positive end-expiratory pressure (P <0.001).

And between the compliance values ​​and the generated one, it produces a positive end-expiratory pressure (P <0.05).

There were no significant differences in carbon dioxide partial pressure and resistance.

Minute ventilation was significantly lower with nasopharyngeal oxygen than at baseline. As expected, the partial pressure of oxygen increased substantially with increasing oxygen fluxes.

Administration of oxygen through an 8F nasopharyngeal cannula at the flow rates recommended by the World Health Organization (0.5 L / min in newborns, 1.0 L / min in infants) produces moderate amounts of positive pressure at the end of expiration.

The levels reached can contribute to an improvement in oxygenation by altering the viscoelastic properties of the lung.

Gastric rupture after delivery of oxygen from the nasopharyngeal cannula

Iatrogenic gastric distention and subsequent rupture after oxygen administration of the nasopharyngeal cannula is a rare but life-threatening condition requiring urgent laparotomy.

Two cases were reported recently; both patients showed abdominal pain and bloating symptoms after oxygen delivery involving a nasopharyngeal cannula during procedural sedation.

The reported oxygen flow rates were 4 L / minute in both cases. The diagnosis was made by emergency imaging. Both patients survived after laparotomy and gastric rupture repair.

Seventeen cases have been reported; for this reason, it is recommended to avoid nasal or nasopharyngeal cannulas and use alternative methods of oxygen administration, such as nasal tips and face masks.