Final answer:
Among the options, Pneumothorax is the condition that requires removing an air pocket using a syringe. This condition involves air entering the space between the lung and the chest wall, causing the lung to collapse.
Step-by-step explanation:
Treatment for Pneumothorax requires surgical intervention with a syringe to remove the air pocket. Among the options provided, epistaxis is the medical term for a nosebleed, emphysema is a long-term, progressive disease of the lungs, and subcutaneous emphysema involves gas or air trapped under the skin. However, it is a pneumothorax, sometimes referred to as a collapsed lung, that necessitates the described procedure. A pneumothorax occurs when air enters the space between the lung and chest wall, causing the lung to collapse, which can impair breathing. In such cases, a procedure known as needle decompression may be used, where a syringe and needle are inserted into the chest cavity to remove the air and allow the lung to re-expand.