Thoracentesis is a procedure to remove fluid or air from the space around the lungs, known as pleural space. A needle is put through the chest wall into the pleural space under strict aseptic precautions under local anaesthesia. The pleural space is a thin gap between the two pleuras- visceral pleura and parietal pleura. Normally, a small amount of fluid is present inside the pleural space.This fluid prevents the two pleuras from rubbing together when you breathe. Excess fluid in the pleural space is called pleural effusion. When this happens, it’s harder to breathe because the lungs can’t inflate fully. This can cause shortness of breath and chest pain.