Effects of Tracheostomy Decannulation on Respiratory Function

Inclusion Criteria: * Age ≥ 18 years. * Tracheostomised patient whose primary illness is stable and who is scheduled for elective decannulation in the rehabilitation unit. * Able to tolerate a one-way speaking valve for ≥ 4 h on the day before planned decannulation. * Capable of following instructions and completing bedside spirometry. * Patient (or legally authorised representative) has provided written informed consent. Exclusion Criteria: * No tracheostomy in place or requirement for re-intubation/re-cannulation after planned decannulation. * Inability to perform lung-function testing either via the tracheostomy tube or via the mouth/nose (e.g., severe upper-airway obstruction, facial deformity). * Unstable cardiopulmonary or neurological status that makes spirometry unsafe (e.g., ongoing myocardial ischemia, uncontrolled arrhythmia, severe agitation). * Any acute condition requiring isolation precautions that preclude study procedures. * Refusal or inability to sign informed consent. * Missing or incomplete key outcome data.