Airway devices [advanced]

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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

A patient presents to ED with chest pain and this trace. What would you do?

Interpretation management

Covered in OSCE Stations

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