Which of the following is not a symptom of mild airway obstruction?

In the context of mild airway obstruction, cyanosis is not typically a symptom observed. Mild airway obstruction usually allows for adequate airflow, and patients can generally breathe adequately, which leads to the absence of blue-tinged skin or mucous membranes commonly associated with significant hypoxia, where cyanosis would be more apparent.

On the other hand, symptoms like noisy respirations, respiratory distress, and coughing are all common indicators of mild airway obstruction. Noisy respirations may occur due to the turbulent airflow through narrowed passages, while respiratory distress can manifest as the patient may still be struggling to breathe but not to the extent that it leads to complete airway blockage. Coughing is a reflex that aids in clearing an obstruction and is often a response seen in cases of mild obstruction where the body is trying to expel the obstruction.

Thus, the presence of cyanosis would suggest a more severe obstruction or inadequate respiratory function, which distinguishes it from the symptoms linked with mild airway obstruction.