Guedel Cannula: Definition, Description, Parts, Insertion Method, Use, Complications and Airway Management

It serves to overcome soft palate obstruction by preventing backward movement of the tongue.

The Guedel cannula or oropharyngeal airway is a device that is designed to be used in patients with a reduced level of consciousness.

They are available in different sizes (2, 3, and 4 most common). The “correct” size should be chosen as measured from the vertical distance from the patient’s incisors and the angle of the jaw.

Caution should be exercised in slightly unconscious patients, as they may not have lost their laryngeal reflexes enough to tolerate an oropharyngeal airway, and retching or laryngospasm may be triggered.


  • Sizes: equal to the length in cm.
  • Suitable for maintaining an unobstructed oropharyngeal airway during general anesthesia and in unconscious patients.
  • Bite block to avoid tongue biting and airway occlusion.
  • Rounded atraumatic edges.
  • Smooth airway trail for easy cleaning.
  • Color code for easy size identification.
  • Color-coded bite portions can help to easily identify size (children – 00, 1, 2, adults -3, 4, 5, 6).


  • Flange to avoid over-insertion.
  • Reinforced bite section.
  • Curved body to adapt to the tongue/palate.
  • Tubular air channel.

Method of insertion and use

  • Children: Insert directly onto the tongue, ideally with the help of a tongue depressor (no 180-degree twist).
  • Adults: rotate 180 degrees from the open position upward as it is inserted over the tongue.

Lubricant can aid in insertion.


  • Retching, vomiting, and aspiration.
  • Soft tissue trauma to the tongue, palate, and pharynx.
  • Biting the hard surface can damage your teeth.

Airway management

Oropharyngeal airway devices should be available in the full-size range at each anesthesia location.

The required airway size can be estimated by careful external examination of the patient and measuring the distance from the teeth to the base of the tongue.


An airway device that is too small can shift the base of the patient’s tongue downward, the degree of obstruction, which can be made worse by CPAP to improve airway obstruction.

A too-large airway can reach the entrance to the larynx and cause laryngeal trauma or hyperactivity and laryngospasm.

It is common practice for some physicians to insert an oropharyngeal airway upside down or convex to the natural curvature of the tongue and then rotate the airway 180 degrees. However, this maneuver can wear down the hard palate and is not recommended.

A less traumatic technique for inserting an air connection device is to use a button to move the tongue to the floor of the mouth and insert the concave device on the surface of the language.

Oropharyngeal airway devices are often used as “bite blocks” after the patient’s trachea has been intubated to avoid clenching the teeth in the endotracheal tube.

However, this maneuver can be dangerous in children between 5 and 10 years of age with loose deciduous teeth.

Airway devices are responsible for up to 55% of anesthesia-related dental complications.

Additionally, when an airway device is used as a bite block during long cases, it can cause necrosis of the tongue, uvular edema, or lip damage.

A gauze pad should be placed between the patient’s upper and lower molar teeth to prevent the tooth from getting stuck in an endotracheal tube and minimize dental trauma.

However, care must be taken that the roll does not slip and exert undue pressure on the lateral aspect of the tongue (paraglossal sulcus), where the hypoglossal nerve runs.

Air navigation devices are generally constructed of red rubber or polyvinyl chloride and are available in various sizes.

A nasal airway must be lubricated and inserted transnasally. Nasopharyngeal airway devices can traumatize turbinates or adenoids in young children.

In addition, care should be taken when using a nasopharyngeal airway device in children who have hemorrhagic diabetes or a congenital abnormality of the midface, such as choanal atresia of frontonasal dysplasia.

The appropriate length for the nasopharyngeal airway can be estimated by measuring the distance between the patient’s auditory meatus and the tip of the nose. Insertion of an airway device that may be too long can cause laryngospasm.

Other information

The Berman Airway is similar but has a difference in size; it can be used to facilitate the passage of a bronchoscope: once inserted into the larynx, the device can be slid out of reach endotracheal tube is inserted into the larynx.

The Cup (Cuffed Oropharyngeal Airway) is a variant with an inflatable cuff to seal the oropharynx and has a universal connector attached to the bite block to allow ventilation – limited popularity and reach.