What is thoracentesis?

Thoracentesis is a procedure to remove extra fluid from around the lungs. Normally the lungs fill up a person's chest. The space between the outside of the lungs and the inside of the chest is called the pleural space. It usually has only a very small amount of fluid that lubricates these surfaces. But if extra fluid builds up in this space, the lung can't inflate all the way. Too much fluid in the pleural space is called pleural effusion. It reduces lung function and makes it harder to breathe.

Thoracentesis is done to remove the extra fluid when it's causing symptoms, such as trouble breathing. Or it can be done to find out why there's too much fluid in the space.

During a thoracentesis, a needle is put through the skin of the chest into the pleural space. This drains the extra fluid.

Why might you need thoracentesis?

Many conditions can cause a pleural effusion. A thoracentesis may be needed to find the cause. When the fluid is drained from around the lung it's then examined in a lab.

Thoracentesis can help diagnose health problems, such as:

• Congestive heart failure. This is the most common cause of pleural effusion.

• Viral, fungal, or bacterial infections. Example of infections that can cause pleural effusion are empyema and tuberculosis.

• Cancer.

• Systemic lupus erythematosus and other autoimmune diseases.

• Inflammation of the pancreas (pancreatitis).

• A blood clot in the lung (pulmonary embolism).

• Liver failure.

• Reactions to medicines.

Your doctor may have other reasons to advise the procedure.

What are the risks of thoracentesis?

All procedures have some risks. The risks of this procedure include:

• Air getting into the pleural space. This can make the lung collapse (pneumothorax).

• Bleeding.

• Infection.

• Liver or spleen injury. This is rare.

Your risks may vary depending on your general health and other factors. Talk with your doctor about your risks and any concerns you have.

Thoracentesis shouldn't be done in people with certain bleeding conditions.

How do you get ready for thoracentesis?

Your doctor will explain the procedure to you. You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully. Ask questions if anything isn't clear.

Tell your doctor if you:

• Are pregnant or think you may be pregnant.

• Are sensitive to or allergic to any medicines, latex, tape, or anesthetic medicines (local and general).

• Take any medicines, including prescriptions, over-the-counter medicines, vitamins, herbs, and other supplements.

• Have had a bleeding disorder.

• Take blood-thinning medicine (anticoagulant), aspirin, or other medicines that affect blood clotting.

Make sure to:

• Stop taking certain medicines before the procedure, if advised by your doctor.

• Plan to have someone drive you home from the hospital.

• Follow any other directions your doctor gives you.

You may have imaging tests before the procedure. These are done to find the location of the fluid to be removed. You may have any of these tests:

• Chest X-ray

• Chest fluoroscopy

• Ultrasound

• CT scan

What happens during thoracentesis?

You may have your procedure as an outpatient. This means you'll go home the same day. Or it may be done as part of a longer stay in the hospital. The way the procedure is done may vary. It depends on your condition and your doctor's methods. In most cases, a thoracentesis will follow this process:

1. You may be asked to remove your clothes. If so, you'll be given a hospital gown to wear. You may be asked to remove jewelry or other objects.

2. You may be given oxygen through a nasal tube or face mask. Your heart rate, blood pressure, and breathing are watched during the procedure.

3. You may be in a sitting position in a hospital bed with your arms resting on an over-bed table. This position helps to spread out the spaces between the ribs, where the needle is inserted. If you are not able to sit, you may lie on your side on the edge of the bed.

4. The skin where the needle will be put in is cleaned with an antiseptic solution.

5. A numbing medicine (local anesthetic) is injected in the area.

6. When the area is numb, the doctor puts a needle between the ribs in your back. You may feel some pressure where the needle goes in. Fluid is slowly drawn into the needle.

7. You will be asked to hold still, breathe out deeply, or hold your breath at certain times during the procedure.

8. If there's a large amount of fluid, tubing may be attached to the needle. This lets more fluid drain out. The fluid drains into a bottle or bag. In some cases, a flexible tube (catheter) may be put in the pleural space and kept there for 1 to 2 days. You will stay in the hospital until the catheter is removed.

9. When enough fluid has been removed, the needle is taken out. A bandage or dressing is put on the area.

10. Fluid samples may be sent to a lab.

11. You may have a chest X-ray taken right after the procedure. This is to make sure your lungs are okay.

What happens after thoracentesis?

After the procedure, your blood pressure, pulse, and breathing will be watched. The dressing over the puncture site will be checked for bleeding or other fluid. If you had an outpatient procedure, you can go home when your doctor says it’s okay. Someone will need to drive you home.

At home, you can go back to your normal diet and activities if advised by your doctor. You may need to avoid hard physical activity for a few days.

Contact your doctor if:

• You have a fever of 100.4°F (38°C) or higher, or as advised by your doctor.

• The needle site is red or swollen.

• Blood or other fluid is leaking from the needle site.

• You're feeling short of breath.

• You have trouble breathing.

• You have chest pain.

Your doctor may give you other directions after the procedure.

Next steps

Before you agree to the test or procedure make sure you know:

• The name of the test or procedure.

• The reason you are having it.

• What results to expect and what they mean.

• The risks and benefits of the test or procedure.

• What the possible side effects or complications are.

• When and where you're going to have the test or procedure.

• Who will do it and what that person’s qualifications are.

• What would happen if you did not have it.

• Any alternative tests or procedures to think about.

• When and how will you get the results.

• Who to contact afterwards if you have questions or problems.

• How much will you have to pay for it.