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A thoracentesis is a procedure to remove extra fluid or air from between your lungs and your inner chest wall. Air or fluid buildup may make it hard for you to breathe. A thoracentesis allows your lungs to expand fully so you can breathe more easily.


Before your procedure:

  • Informed consent is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.
  • An IV is a small tube placed in your vein that is used to give you medicine or liquids.
  • You may need extra oxygen if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask your healthcare provider before you take off the mask or oxygen tubing.
  • Tests:
    • Blood tests: You may need blood taken to give caregivers information about how your body is working. The blood may be taken from your hand, arm, or IV.
    • Chest x-ray: This is a picture of your lungs and heart. Caregivers use it to see how your lungs and heart are doing. Caregivers may use the x-ray to look for signs of infection like pneumonia, or to look for collapsed lungs. Chest x-rays may show tumors, broken ribs, or fluid around the heart and lungs.
  • Monitoring:
    • Vital signs: Caregivers will check your blood pressure, heart rate, breathing rate, and temperature. They will also ask about your pain. These vital signs give caregivers information about your current health.
    • A pulse oximeter is a device that measures the amount of oxygen in your blood. A cord with a clip or sticky strip is placed on your finger, ear, or toe. The other end of the cord is hooked to a machine.

During your procedure:

  • You will be given local anesthesia to numb the area where the needle will be inserted. Your healthcare provider will insert the needle and move it between your ribs. He may use an ultrasound to help guide the needle.
  • If your procedure is done to collect fluid for tests, a small amount of fluid is removed. Then the needle is removed and a dressing is placed over the area. If more fluid needs to be drained, a small plastic tube will be placed and the needle removed. The tube will be connected to a collection device and the fluid will slowly drain out. A device may be used to measure the pressure inside your chest. This will help your healthcare provider check if enough fluid has been drained. When enough fluid has drained out, the tube will be removed and the area will be covered with a dressing.

After your procedure:

You will need to stay in bed and rest after your procedure. When your healthcare provider sees that you are okay, you will be allowed to go home. If your healthcare provider wants you to stay in the hospital, you will be taken to your hospital room. A chest x-ray may be needed to check that your lungs were not damaged during the procedure. You may also need any of the following after your procedure:

  • Chest tube: This is a tube that is placed into your chest to drain extra fluid. The chest tube is attached to a container to collect the fluid. Call a healthcare provider right away if the tube comes apart from the container. Let the healthcare provider know if the tubing gets bent, twisted, or the tape comes loose.
  • You may need extra oxygen if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask your healthcare provider before you take off the mask or oxygen tubing.
  • Medicines:
    • Pain medicine: You may be given medicine to decrease pain. Do not wait until the pain is severe before you ask for medicine. Pain medicine can make you dizzy or sleepy. Prevent falls by calling a healthcare provider when you want to get out of bed or if you need help.
    • Antibiotics: This medicine helps fight or prevent an infection.
    • Breathing treatments: You may need breathing treatments to help open your airways so you can breathe easier. A machine is used to change liquid medicine into a mist. You will breathe the mist into your lungs through tubing and a mouthpiece. Inhaled mist medicines act quickly on your airways and lungs to relieve your symptoms.


  • Your lung may be punctured by the needle and collapse. You may bleed more than expected or get an infection from the procedure. You may also have chest pain, a cough, nausea, or feel lightheaded. Nerves, blood vessels, and nearby organs, such as your liver and spleen, may get damaged. Even after your procedure, the air or fluid in your chest may not drain completely. The air or fluid may build up again and you may need another thoracentesis.
  • Without a thoracentesis, the extra air or fluid may continue to build up in your chest. Your breathing problems will get worse. You may need to have other procedures to drain the air or fluid. Your healthcare provider may not be able to learn more about the cause of your condition. You may not get the treatment that you need.


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.