Written by Jaime Herndon | Published on August 7, 2012
Medically Reviewed by George Krucik, MD

What is a Thoracentesis?

Between the lungs and the chest wall there is a small space called the “pleural space.” This space typically contains approximately four teaspoons of fluid. Certain conditions, including tumors, pneumonia, heart failure, or lung illnesses, can cause more fluid to enter the space. This is called pleural effusion. When there is an excess of fluid, it can compress the lungs and cause difficulty breathing.

Thoracentesis is a procedure done when there is too much fluid in the pleural space, making it hard to breathe. The primary goal is to drain the fluid and make it easier for you to breathe again. In some cases, the procedure will also help your doctor discover the cause of the pleural effusion.

The amount of fluid that is drained may vary depending on the reasons for performing the procedure. It typically takes 10 to 15 minutes, but it can take longer if there is a lot of fluid in the pleural space.

Your doctor may also perform a pleural biopsy at the same time, to get a piece of tissue from the inner chest wall lining. Abnormal results on a pleural biopsy could signal one of a number of different possible causes for the effusion, including the presence of lung cancer, mesothelioma, tumors, collagen vascular disease, viral or fungal diseases, or parasitic disease.

Preparing for a Thoracentesis

There is no special preparation for thoracentesis. Tell your doctor about any supplements or medications you are taking, or if you have any bleeding problems.

What Is the Procedure for Thoracentesis?

Thoracentesis can be done in a doctor’s office or in a hospital. You are typically awake, although some individuals may be sedated. If you are sedated, you will need someone else to drive you home after the procedure.

After sitting in a chair or lying on a table, you will be positioned in a way that allows the doctor tp access the pleural space. An ultrasound may be done to ascertain the correct area where the needle will go. The selected area will be cleaned and injected with a numbing agent.

Your doctor will insert the needle or tube below your ribs into the pleural space. You might feel pressure or be uncomfortable, but you should not move. The excess fluid will then be drained out.

Once all the fluid is drained, a bandage will be put on the insertion site. To ensure there are no complications, you will be asked to stay in the office for several hours to be monitored. A follow-up X-ray is typically ordered two to four weeks after thoracentesis.

Is Thoracentesis Right for Everyone?

Thoracentesis is not a safe or appropriate procedure for some patients. After talking with your doctor, he or she will determine whether you are a good candidate for thoracentesis. Patients who have had recent lung surgery may have scarring, which can make the procedure difficult.

Patients who should not undergo thoracentesis include:

  • patients with a bleeding disorder
  • patients with heart failure or enlargement of the right side of the heart
  • patients on blood thinners

Are there Risks to the Procedure?

Every invasive procedure has risks, but side effects are uncommon with thoracentesis. Possible risks include:

  • pain
  • bleeding
  • collapsed lung
  • infection

Your doctor will go over the risks prior to the procedure.

Following Up After the Procedure

Once you are home, call your doctor if you have trouble breathing or coughing up blood, if you are in pain when taking deep breaths, or if you have any new bleeding from the needle site.

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