Invasive tests – Pleural Tap (Thoracentesis)

There are many reasons for fluid to build up:

  • Infection of lung or infection of the pleural space called ‘empyema’.
  • Cancer.
  • Bleeding into the space called ‘haemothorax’.
  • Autoimmune diseases like rheumatoid arthritis.
  • Pulmonary embolism - blockage of an artery by a substance which has travelled from another site to the arteries in the lung.
  • Blockage of the lymphatic drainage system causing a build up of fatty fluid called a ‘chylothorax’.

This refers to sampling a pleural effusion. This is usually done with a local anaesthetic and the person is awake.

  • The presence of the effusion will be confirmed with an ultrasound scan and a safe place to take a sample from will be marked.
  • A small needle, similar to one used to take blood tests, is inserted between the ribs until it reaches the effusion.
  • The fluid is removed with a syringe and sent away for analysis.

If pleural effusions continue to occur despite drainage, a device called an indwelling pleural catheter (IPC) may be inserted to drain fluid. A high level of hygiene is needed to prevent infection. If the IPC does become infected it will be removed and the patient will be given antibiotics.