Tracheostomy fenestration: Does it increase upper airway flow?

The study is a randomised crossover comparison of fenestrated and non-fenestrated inner cannulas in a corked, uncuffed fenestrated double lumen tracheostomy tube. Specifically: (a) Participants will have their inner cannula changed by the primary investigator on four occasions following successful tracheostomy occlusion (b) Inner cannulas (fenestrated and non-fenestrated) will be changed two times each (4 separate occasions), with each in-situ for 60 minutes following the change. The order of change will be randomised to ABAB or BABA, where A=fenestrated and B=non-fenestrated. Data collection (via spirometry and digital voice recording) will take place 60 minutes following each change, immediately prior to the next change. Data collection will therefore be completed in 4 hours. (c) The primary investigator (speech pathologist) will be administering the intervention. (d) The key difference between the fenestrated and non-fenestrated inner cannulas are that the fenestrated cannula has a hole (fenestration) in the outer curve that when in-situ is aligned with the fenestration of the outer cannula. As such, air can pass through the fenestration of the outer tube when the fenestrated inner cannula is in-situ, but not when the non-fenestrated inner cannula is in-situ (as the outer fenestration will be blocked). This is why the protocol is a crossover comparison of inner cannulas within a fenestrated outer cannula, in order to measure the difference in airflow with the fenestration open or closed. (e) Nursing / medical records will be consulted (and discussion with the treating nurse) to ensure that there are no deviations to the protocol in between testing. A deviation could be that the cork/cap is removed by the patient due to difficulty breathing. There is a 60 minute period following each inner cannula change before the assessments are performed.