Endoscopy
Endoscopy is used in examinations of the upper and lower respiratory tracts (laryngoscopy and bronchoscopy) to identify and localize causes of respiratory sounds/problems (e.g. roaring due to laryngeal hemiplegia). In cases of respiratory infection or bronchitis, a sample of the secretions can be taken from the trachea and the bronchial tubes using an endoscope and sent for testing to determine what caused the infection or whether there is an allergic reaction.