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Thoracentesis is a medical procedure performed to find out the cause of fluid accumulation and the amount of fluid accumulated around the lungs. The other name for the procedure is pleural tap. When excessive fluid accumulates in the pleural space, your doctor will recommend Thoracentesis. He or she will ask for a pleural fluid analysis to be performed in the lab to find out the root cause behind fluid accumulation around your lungs. Pleural space is a small space present between your lungs and your chest wall. Normally, it contains around 4 teaspoons of fluid.

Excess of fluid can cause difficulty in breathing because of compression of the lungs. Thoracentesis involves draining the fluid to allow breathing. Your doctor may also use the procedure to figure out the cause behind pleural effusion. He or she may also opt for a pleural biopsy to obtain tissue from your inner chest wall lining. If the results of a pleural biopsy are abnormal, it indicates some cause of effusion like:

  • Mesothelioma (asbestos-related cancer in the tissues covering the lungs)
  • Fungal or viral diseases
  • Lung cancer or the presence of cancer cells
  • Collagen vascular disease
  • Parasitic disease

Why do I need a Thoracentesis?

Your doctor will remove the fluid from the pleural space during Thoracentesis. This will help in easing down your chest pain, shortness of breath and the pressure on your lungs. He or she will then test the fluid for finding out the reason for its accumulation. Most commonly, it is due to congestive heart failure. This happens when your heart is not able to pump blood to your body properly. More fluid may enter this pleural space because of some conditions that may be:

  • Pulmonary hypertension
  • Lung infection or pneumonia
  • Tuberculosis
  • Empyema (an area of pus present in the pleural space)
  • Chronic lung disease
  • Liver failure
  • Blood clots in the lungs
  • Cancerous tumors
  • Fungal, viral or bacterial infection
  • CHF or congestive heart failure

Preparing for Thoracentesis

Your doctor will instruct you regarding the procedure.

  • Inform your doctor if you are expecting a baby
  • You may need to go for a blood test before Thoracentesis. It reveals the condition of your kidneys and you must let your doctor know if the blood clots normally in your body.
  • You must have someone with you to take you back home after the procedure. This is because there will be some effect of the sleeping medicine given before the procedure to numb your pain.
  • Inform your doctor about all the medications or supplements that you take and allergies, if you have any. Also, let your doctor know if you have an allergy to anesthesia (sleeping medicine).

What to expect?

You will need a chest X-ray of the lungs either before the procedure or after the procedure. It helps to check your lungs.

During the procedure

  • Your doctor will ask you to sit on a chair or bed while your arms rest on the table. This helps to open up the space between the ribs.
  • Your doctor will clean and numb the specific area to insert the needle. He or she will give medicine to young children to make them sleepy.
  • He or she will insert the needle in your back between the ribs and withdraw the fluid.
  • You will have to stay still and hold your breath or exhale at different times.
  • After drainage of adequate fluid, your doctor will remove the needle and bandage the area. The needle site will close without the use of any stitches after some days.
  • If there is a lot of fluid, then it may require a long time for the procedure to end, otherwise, it is a 15 minutes procedure.

After the procedure

  • Your doctor will send the fluid samples for examination.
  • A nurse will monitor your pulse, blood pressure and breathing.
  • He or she may also check your bandage before allowing you to go home.


After a thorough evaluation of your fluid in the lab, your doctor will tell you the outcomes of the procedure. He or she will then make a suitable treatment plan for you to eliminate the problems arising or the underlying condition. If you are suffering from an infection because of bacteria in your body, then your doctor will treat the infection with antibiotics.


Your doctor will recommend an X-ray of your lungs after Thoracentesis and will monitor your vitals. If your oxygen saturation, pulse, breathing rate and blood pressure are normal then he or she will allow you to go home. However, many people get to head back home on the same day as that of Thoracentesis. You will be able to perform most of the routine activities immediately after the procedure. You will have to refrain from doing physical activities after the procedure for a few days.

Your doctor will give you instructions on caring for the puncture site. If you notice any signs of infection then you must immediately call up your doctor. The signs and symptoms of infection may be:

  • Coughing of blood
  • Pain while taking deep breaths
  • Fever
  • Troubled breathing
  • Redness and pain
  • Chills
  • Bleeding around the puncture site or needle site


Although there are no side effects, there are some risks associated with it. Risks associated with Thoracentesis are:

  • Bleeding
  • Pulmonary edema
  • Infection at the needle site
  • Pain
  • Collapsed lung because of air accumulation (pneumothorax)
  • In rare cases, spleen or liver injury


Your doctor will keep in view the risks before doing the procedure. Thoracentesis is not a suitable procedure for all. So, your doctor will first determine if it would be helpful for you and whether you are a good candidate for it. People who have scarring because of lung surgery recently cannot opt for the procedure as it becomes difficult. If you are taking blood thinners, had heart failure, have a sleeping disorder or have enlargement of the heart with the lungs trapped then you must not go for Thoracentesis.

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