Airway devices [advanced]

Please note content is for educational purposes only and procedures should not conducted based on this information. OSCEstop and authors take no responsibility for errors or for the use of any content.

Nasopharyngeal airway

• Flexible rubber tube which goes through the nose and ends at base of tongue (an adjunct to help keep airway open)
• An oxygen mask or bag-mask ventilation can be applied over the top if needed
• Function: prevents tongue covering epiglottis in patients with reduced GCS. It is better tolerated than oropharyngeal airways in more alert patients.
• Contraindications: base of skull fractures, nasal trauma, coagulopathies, nasal obstruction, recent nasal surgery
• Size: 6-7mm diameter for most adults; tube diameter should be similar to nostril size

Oropharyngeal airway (Guedel)

• Rigid plastic tube which sits along top of oral cavity and ends at base of tongue (an adjunct to help keep airway open)
• An oxygen mask or bag-mask ventilation can be applied over the top if needed
• Function: prevents tongue covering epiglottis in patients with reduced GCS
• Size: should be similar to distance between the incisors and the angle of jaw; size 3 (orange) for medium adult

Supraglottic airway (usually i-Gel)

• Flexible plastic tube with a cuff on the end which sits over top of larynx. Provides some protection against aspiration but does not fully secure airway and can only withstand a small amount of positive pressure ventilation.
• Can be attached to ventilation bag in respiratory arrest; or, during surgery, to ventilator which allows spontaneous ventilation ± low-level positive pressure ventilation supplementation
• Function: airway protection during anaesthetic for surgery (if no risk of aspiration and a muscle relaxant is not required); respiratory arrest; if endotracheal intubation is indicated but fails, or the clinician is not trained in intubation   
• Size: 4 (green) for average adult

Endotracheal tube

• Flexible plastic tube with cuff on end which sits inside the trachea (fully secures airway – gold standard)
• Attached to ventilation bag/machine
• Function: ventilation during anaesthetic for surgery (if muscle relaxant is required, long case, abdominal surgery, or if head positioning may be required); if patient cannot protect their airway (GCS <8, aspiration risk, muscle relaxation); potential airway obstruction (airway burns, epiglottitis, neck haematoma); inadequate ventilation/oxygenation (e.g. COPD, head injury, acute respiratory distress syndrome)
• Rapid sequence induction intubation = procedural variant using rapid anaesthetisation with cricoid pressure to prevent aspiration while airway is quickly secured – used for patients at risk of aspiration, e.g. non-fasted patients
• Size: 8mm diameter for average male, 7mm diameter for average female

Tracheostomy

• Surgical hole made in trachea, through which a tracheostomy tube is passed
• Attached to ventilation bag/machine
• Function: a tracheostomy is performed for long-term ventilation in intensive care
• NB: a needle or surgical cricothyroidotomy is different and is used in the emergency setting when an acute upper airway obstruction is preventing endotracheal intubation