This procedure involves drainage of fluid from around the lung through a needle or plastic tube which is guided into place using an ultrasound, CT or x-ray machine.


You will lie or sit on the ultrasound bed in the best position for the drainage. Your skin will be cleaned with antiseptic and local anaesthetic will be given.

For a diagnostic tap, the radiologist will insert a fine needle to obtain a sample of fluid. Once the needle is removed, a small dressing (bandage) is placed on the skin.

For a pleural drain, a small incision (cut) is made in the skin. A needle is usually inserted first and then a wire and a plastic tube which can be left in to drain the fluid. It may be necessary to make more than one pass of the needle to get it into the best position. The tube will be held in position by a dressing (bandage) on the skin.

Usually, a short-stay hospital admission is arranged to allow the fluid to drain over several hours.

The drain may stay in overnight if you are an inpatient. Rarely, the tube is left in for longer.

The drain can be removed easily on the ward, and a small dressing (bandage) will be put on.

Risks / Side Effects

Potential risks include:

  • Infection at the drainage site. Aseptic technique (strict infection control practices) is used to minimise the risk of infection.
  • Puncture of a blood vessel. The needle may puncture a blood vessel and cause bleeding. Rarely, excessive bleeding can occur and may require drainage, transfusion or surgery.
  • Puncture of the lung. The needle may puncture the lung, allowing air to leak out into the surrounding space. If small, this will be followed up without treatment. If large, a chest drain may need to be inserted.

Before your Scan

It is essential that your previous x-ray, CT or ultrasound films are available at the time of the drainage. If you have them, please bring these with you to your examination.

Please tell us if you are on medication to thin your blood (e.g. Warfarin, Aspirin or Clopidogrel). You may need to stop this before to the procedure, but you must discuss this with your doctor first.

It is important that you have someone to drive you home after the procedure.

Other Information

Once the drain is removed a dressing (bandage) will be put on. There may be a small ooze from the site which should stop after a few hours.

Avoid strenuous activity for 24 hours after the drainage procedure.

You may experience some discomfort. If required, a simple analgesic such as paracetamol (Panadol) should provide some relief. Do NOT use Aspirin.

Potential complications include infection and air leak. If you notice any increased redness, swelling, fever or pain around the drainage site, or increasing shortness of breath or pain on breathing, notify your referring doctor or immediately call the clinic where the drainage was performed.

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