The use of upper airway structures in a patient with a tracheostomy is a sort of delicate art, resembling the use of a brass or woodwind instrument, involving timing and the deliberate obstruction of various important fingerholes in order to produce speech. In the CICM Part II exam, this topic has come up as a whole 10-mark question (Question 17 from the first paper of 2017) as well as in the context of more equipment related discussions regarding Passy-Muir valves and suchlike.

An excellent overview of the possible methods (including their advantages and disadvantages) is afforded through the excellent 2005 article by Dean R Hess. Those six pages are probably enough for most candidates. The brief summary which follows has been assembled largely from Hess, as well as a couple of other contributors. Given the nature of Question 17 from the first paper of 2017, discussion should probably take the shape of a table describing the advantages and disadvantages of various strategies.

Advantages and Disadvantages of Various Methods for

Allowing Speech in Tracheostomy Patients
Method Advantages Disadvantages

Cuff up, fenestrated tube:
Gas flow is via an additional port above the cuff; 4-6L/min flow. The pt. remains ventilated
  • Allows speech with an inflated cuff
  • Decouples speech and breathing: no loss of ventilation during speech
  • Unless this tube is already in situ, this will require a tube change.
  • Voice quality is poor (whisper) unless you increase the flow to an uncomfortable level
  • Secretions from above can clog the tube
Cuff down, speaking valve:
Gas only exits through the upper airway during exhalation
(one way valve)
  • No need to change the tracheostomy tube
  • Flow rate is good: speech volume resembles normal speech
  • Speech is possible during inspiration and expiration, if ventilated and on PEEP
  • Works best if the patient is not on a ventilator
  • With a ventilator, need to compensate for a high volume of leak (most ventilators will not tolerate this)
  • The cuff needs to be deflated (i.e. the airway is not protected from aspiration)
  • There are many contrandications to such a speaking valve
Cuff down, no speaking valve
i.e. gas freely exists via both the tracheostomy and the upper airway
  • No need to change the tracheostomy tube
  • Flow rate is good: speech volume resembles normal speech
  • Only works in ventilated patients 
  • Only able to speak in inspiration, unless PEEP is high
  • Again, there is a large volume of leak
  • The leak may affect ventilation (i.e. PaCO2 may rise)
Cuff down, finger occlusion - i.e. the patient blocks the tracheostomy and exhales using the upper airway instead
  • No need to change the tracheostomy tube
  • Flow rate might be good (depending on muscle strength)
  • Requires a lot of coordination
  • With the cuff down, no protection from aspiration

References

Hess, Dean R. "Facilitating speech in the patient with a tracheostomy."Respiratory care 50.4 (2005): 519-525.

Morris, Linda L., et al. "Restoring speech to tracheostomy patients." Critical care nurse 35.6 (2015): 13-28.