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What is Thoracentesis?

A thoracentesis is a procedure to remove excess fluid that has built up in the space between the linings of the chest wall and the lungs (pleural space). The excess fluid between the chest wall and lung is called a pleural effusion.

What do we do about them?

Most seromas and lymphoceles are asymptomatic. They can be incidentally found on post-surgical imaging. Depending on the size and symptoms, they may not require treatment and resolve on their own. However, if they are symptomatic or there is concern that the fluid might be infected, then it may require drainage or surgery.


Why do I need this procedure?

You developed fluid in your chest that has compressed the lung.  This fluid has accumulated in an area called the pleural space and the fluid is called a pleural effusion.  This can happen on the right side, left side, or sometimes on both sides.  The more fluid that accumulates, the less space exists for the lung to expand.  With a very large pleural effusion the lung can be nearly completely collapsed.  This can cause you to have difficulty breathing, especially when you walk or do any sort of activity.

There are many reasons why this fluid has accumulated and sometimes we don’t know –  in which case we will send the fluid for various tests.  We may need to draw some blood at the same time to compare test results between the blood and fluid.

How the procedure is done:

You may be asked to stop any blood thinner medication you are taking prior to procedure.

For the procedure:

● You will be asked to sit upright on the side of the exam table and lean slightly forward with your arms on a stand.

● A limited chest ultrasound will be performed to evaluate for a pleural effusion.

● The procedure site will be marked and cleaned.

● A medicine to numb the area (local anesthetic) will then be injected to the procedure site.

● A small needle with a catheter on it will be inserted into your back so that it goes between the ribs and into the pleural space.

○ You may feel pressure or slight pinch as the needle is positioned into the pleural space.

● The needle will be removed and a catheter will remain in the pleural space attached to a vacuum sealed bottle.

○ You may feel pressure or the urge to cough as the fluid is removed.  This is a temporary feeling.

● Once the fluid is removed the catheter will be removed.

● The puncture site will be covered with sterile skin glue.

● A sample of the fluid may be sent to the lab for testing.

What are the risks?

Using ultrasound guidance during thoracentesis helps keep the risks low.  As with any procedure, there is a small risk of bleeding at the puncture site and a very small risk of infection.  Specifically for thoracentesis, since the fluid being drawn out is in the pleural space outside of the lung, there is a very small risk of a lung puncture during the procedure that could lead to a lung collapse also known as a pneumothorax.  Using ultrasound helps visualize the lung border and where the pleural effusion is to keep the risk very low. 

General Instructions:

Activity and Diet

● You may resume your regular activities (including driving) after 24h, unless you have been restricted for another reason.

● No exercising, lifting have objects or strenuous activity for the next 24h.

● You may shower the same day as the procedure.

● You can resume your normal diet.  

Pain Management

● You may use ice over the procedure site and/or over the counter medication such as acetaminophen (Tylenol) or ibuprofen (Advil /Motrin) for minor discomfort, unless you are restricted from taking these medications.

● If you feel that Tylenol or Advil are not enough for pain control, please contact the Vascular and Interventional Radiology Clinic at 650-404-8445.

What should I watch for?

You may be sore after the procedure, but this should not get worse and should subside within a  day or two.  However, these are the things you should watch for:

● Increased chest pain on the side of the thoracentesis.

● Increased difficulty breathing

● Fever >101.5F

You can reach your Interventional radiologist at 650-404-8445 during M-F 8-5pm, or the physician can be reached through the operator after hours or on weekends by calling 408 739-6000 and asking for the Interventional Radiologist “on call.”

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