Upper airway non-patency is defined as positive; otherwise, it is negative. The true positive group is defined as those for whom both the results of the speaking valve (SV) with the transtracheal end-expiratory pressure (TTPEE) measurement protocol and the bronchoscopy are positive.

Upper airway non-patency is defined as positive; otherwise, it is negative. The false positive group is defined as the group in which the result of the speaking valve (SV) with the transtracheal end-expiratory pressure (TTPEE) measurement protocol is positive, and the result of the bronchoscopy is negative.

Upper airway non-patency is defined as positive; otherwise, it is negative. The true negative group is defined as those for whom both the results of the speaking valve (SV) with the transtracheal end-expiratory pressure (TTPEE) measurement protocol and the bronchoscopy are negative.

Upper airway non-patency is defined as positive; otherwise, it is negative. The false negative group is defined as the group in which the result of the speaking valve (SV) with the transtracheal end-expiratory pressure (TTPEE) measurement protocol is negative, and the result of the bronchoscopy is positive.

All patients wore speaking valves for 30 minutes, during which the transtracheal end-expiratory pressure was measured to assess the patency of the upper airway.

Patients enrolled in the study will undergo both SV with transtracheal end-expiratory pressure measurement and bronchoscopy. Upper airway non-patency will be defined as positive. Using the results of bronchoscopy as the gold standard, the sensitivity and specificity of SV with transtracheal end-expiratory pressure measurement will be evaluated.