Stridor or noisy breathing can be divided into inspiratory (source is glottic or above), expiratory (intrathoracic trachea or below) or mixed (subglottis or extrathoracic trachea). All patients with stridor, both paediatric and adult, are potentially at risk of asphyxiation and should be investigated fully. Severe stridor may be an indication for either intubation or a tracheostomy (Table 20.3).

Tracheostomy tubes may be:

• Cuffed or uncuffed. A high-volume, low-pressure cuff is used to prevent aspiration and to allow positive-pressure ventilation.
• Fenestrated or unfenestrated. This is a small hole on the greater curvature of the tube (both outer and inner) allowing air to escape upwards to the vocal cords and therefore the patient can speak. This tube often has a valve which allows air to enter from the stoma but closes on expiration, directing the air through the fenestration.

Most long-term tracheostomy tubes have an inner and outer tube. The inner tube fits inside the outer tube and projects beyond its lower end. A major problem with a tracheostomy tube is crusting of its distal end with dried secretions and this arrangement allows the inner tube to be removed, cleaned and replaced as frequently as required, without disrupting the outer tube.

When to decannulate a patient is often a difficult issue if laryngeal competence is unclear. Movement of the vocal cords requires an ENT examination but owing to the risk of aspiration, a speech therapist’s opinion can also be useful. The tracheostomy tube itself can also give problems due to compression of the oesophagus with a cuffed tube and by preventing the larynx from rising during normal swallowing.

Table 20-3. Indications for tracheostomy

Upper airway obstruction (real or anticipated)

Long-term ventilation

Bronchial lavage

Incompetent larynx with aspiration