You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Direct bronchoscopy can visualize all of the following structures, EXCEPT: and explain in detail?
A bronchoscope is used to directly inspect and examine the larynx, trachea and the bronchus. Subcarinal lymph nodes cant be visualised using this. Bronchoscopy helps in visualisation upto the 4th to 5th division of the tracheobronchial tree. Major indications for bronchoscopy in ICU: DIAGNOSTIC BRONCHOSCOPY Airway inspection Collection of respiratory specimens Inspection of endotracheal tube position THERAPEUTIC BRONCHOSCOPY Aspiration of secretions Treatment of obstruction Foreign body extraction Endotracheal tube repositioning Percutaneous dilational tracheostomy tube placement Airway prosthetic placement .