Introduction What Is A Thoracentesis?

A thoracentesis is a procedure involving putting needle into a fluid collection in the chest and removing fluid. A small sample of fluid is taken for testing, but larger amounts of fluid which can cause discomfort or limit breathing can also be removed.

How Is A Thoracentesis Done?

This is done by a doctor in your hospital room or in a treatment room. First, a nurse will check your blood pressure and pulse. You will be asked to sit on the edge of the bed with your arms resting on the overbed table. The area where the needle will go will be cleaned. An anesthetic will be put into the skin to numb the area. This may sting a bit.  After the area is numbed, the doctor will put in the needle to get the fluid.  You may feel some pressure as this needle is going in.

Try to relax and breathe normally. Tell the doctor if you feel short of breath or dizzy. Try not to cough or move suddenly. You may feel some pressure while the fluid is being removed.


Thoracentesis, like all procedures, has some risks. There is a small chance of the following complications occurring:

  • Unusual reaction to the local anesthetic
  • Pneumothorax (collapse of part of the lung)
  • Bleeding
What Should I Expect After A Thoracentesis?

When the procedure is over, the doctor will remove the needle and a bandage will be put over the area. The nurse will check your blood pressure and pulse again. You should rest quietly for a time to allow the needle hole to seal.  Call the nurse if you have any trouble breathing. A chest x-ray may be taken.

The area may feel tender for a few days. You may need to change the bandage if it becomes wet.  Samples of the fluid will be examined and a report sent to your doctor.

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