Thoracentesis, a procedure in which a needle is inserted through the chest wall to remove fluid from a pleural effusion. Pulmonary function tests comprise several different tests which can help to diagnose lung disease and also monitor the response of disease to treatment. Biopsies and bronchoscopies are also performed by the pulmonologist. Bronchoscopy is another procedure in which a flexible tube is inserted into the mouth and down the trachea into the bronchus to look for cancerous.  Mediastinoscopy, a procedure is often done to see if the lung cancer has spread to lymph nodes that exist in the area in the central chest region.