Which description correctly defines thoracentesis?

• A. It removes fluid from the pleural space around the lungs
• B. It removes air from the pleural space
• C. It measures oxygen saturation
• D. It assesses lung volumes

Answer: (A)

Thoracentesis is a procedure specifically to drain fluid from the pleural space surrounding the lungs. By inserting a needle or small catheter into that space, fluid can be removed to relieve shortness of breath from a pleural effusion and/or to obtain a sample for laboratory analysis to determine causes like infection, malignancy, or inflammatory processes. The procedure is often done with the patient seated and leaning forward or lying on the side, using sterile technique and local anesthesia, and is followed by monitoring for possible complications such as a pneumothorax, bleeding, or infection. A chest X-ray after the procedure checks for any air in the pleural space or re-accumulation of fluid.

Understanding why this describes thoracentesis helps: removing air from the pleural space is what’s done in a pneumothorax (often with a chest tube or needle decompression), not for fluid drainage. Measuring oxygen saturation or assessing lung volumes are noninvasive tests or measurements used to evaluate respiratory status, not drainage procedures.