Paracentesis (draining fluid from the tummy)

It's normal to have a small amount of fluid in your tummy (abdomen). If too much fluid builds up, it is called ascites. There can be different reasons for this build-up of fluid, but it is common in people with liver disease.

If you have too much fluid in your tummy, paracentesis is a procedure to drain or remove it. A doctor or specialist nurse in gastroenterology (the branch of medicine that deals with the digestive system, including the liver) does the procedure as day surgery. This means that you do not need to stay in hospital overnight.

You can have the procedure on a ward, usually Alan Apley ward at St Thomas’ Hospital, or in the emergency department (A&E).

Symptoms of ascites

As your tummy gets swollen with fluid, you may: 

  • have tummy pain
  • find it difficult to breathe
  • have difficulty walking 
  • not feel like eating (reduced appetite)
  • feel sick (nausea) and be sick (vomit)

Treatment for ascites

To help your symptoms, we need to remove the extra fluid in your tummy. We usually do this by giving you diuretics (tablets that make you pee more). 

Sometimes the tablets stop working or cause side effects. The best way to ease your symptoms is then to drain the fluid. This procedure is called paracentesis. To do the procedure, we put a plastic tube (drain) into your tummy through the skin.

If ascites is not treated, you will feel uncomfortable and get more serious symptoms.

We want to involve you in decisions about your care and treatment. If you decide to have the paracentesis procedure, we ask you to sign a consent form. This says that you agree to have the treatment and understand what it involves.

If you would like more information about our consent process, please speak to a member of staff caring for you.

Preparing for paracentesis

We may arrange some blood tests before the procedure to make sure that it is safe to do it.

Please tell the doctor or nurse if you take any blood-thinning medicines (anti-coagulants or anti-platelets). They explain if you need to stop these medicines before your procedure.

If you are on diuretics, do not take them on the day of your procedure.

You stay in hospital for about 8 hours. You need to bring a responsible adult, who can take you home after the procedure. It is also a good idea to bring a change of clothes with you.

On the day of paracentesis

Your appointment letter tells you what time to arrive and where to go. You may already be in hospital. We do everything that we can to avoid delays, but they can sometimes happen. If there is a delay, we update you regularly.

We ask you a few questions about your medical history (past or present conditions and treatments). Next, we attach monitors to you to record your:

  • pulse
  • oxygen level
  • blood pressure
  • heart rhythm

These are called observations.

We put a plastic tube (cannula) into a vein in your arm to give you protein (albumin) while the fluid drains. You lie flat on your back during the procedure. We examine your tummy to find the best place to put in the drain. We may need to use an ultrasound to help with this.

We clean your skin with an antiseptic solution and give a small injection of local anaesthetic to make the area numb. Then, we put a tube into your tummy. We collect a small amount of fluid and send it to a laboratory for testing.

After we have put in the tube

The tube is attached to a bag to collect the fluid in your tummy. We empty this bag several times and measure the fluid that is being drained. In this way, we can make sure that we give you the right amount of protein through your cannula.

When the drain is in place, you can sit up if it is more comfortable. You can also get up to use the toilet. The drain stays in for up to 6 hours and we regularly monitor your observations.

After 6 hours, we remove the drain. We cover the area of the drain with a waterproof dressing. You need to keep this dressing as dry as possible for 48 hours and then take it off. We also remove your cannula.

If all your observations are stable, you can leave hospital. Rarely, people become ill during the procedure and may need to stay in hospital.

Recovery after leaving hospital

  • Weigh yourself regularly (1 time each week) and keep a record of this for future appointments.
  • Have a low-salt diet to prevent fluid from building up again.

Make sure you tell your healthcare team if:

  • fluid leaks from the site (area) of the drain after 72 hours (you may need a small stitch to stop this)
  • you notice any signs of an infection, such as redness, swelling or pain at the drain site


Paracentesis is generally safe, but complications can sometimes happen.

Common complications 

  • Tiredness.
  • Low blood pressure.
  • Tummy pain.
  • Fluid leakage from the drain site. This can happen up to 72 hours later.
  • Sometimes, we cannot find a suitable area to put in the drain. If this happens, we may need to send you to the X-ray department for the procedure.

Rare complications (which affect about 1 in 1,000 patients)

  • Infection in the tummy or skin.
  • Bleeding into the tummy, or from the skin, at the drain site.
  • Damage to organs inside the body.

Useful information

The British Liver Trust charity supports people with liver conditions.

The Guts UK charity supports people with conditions that affect the digestive system, including the liver.

Resource number: 5039/VER2
Date published: June 2022
Review date: August 2023

Contact us

If you have any questions or concerns after the procedure, please contact the nurse specialist on Alan Apley ward at St Thomas' Hospital.

Call: 020 7188 8861, Monday to Friday, 8.30am to 5pm

You can also email [email protected] We aim to respond within 48 hours.

Outside of these hours, please contact your GP or you may need to go to your nearest emergency department (A&E).

For questions or concerns about your medicine, or if you need another supply of medicine, please contact the gastroenterology pharmacy.

Email: [email protected].

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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