Are you having back pain with any of the following?

  • Severe pain, weakness or tingling in your leg(s).
  • Difficulty stopping urination or loss of control of bladder or bowels.
  • Unexplained fever, nausea or vomiting.
  • A history of cancer or unexplained weight loss.

We understand that you are experiencing one or more of the health issues that might be impacting your back pain.

We recommend that you discuss these health issues with your doctor before proceeding with this program.

Once you are cleared by your doctor to do this program, we hope it helps you find relief from your back pain.



Thoracentesis is a procedure that removes excess fluid from the space between your lungs and chest wall (pleural space). This space normally contains a small amount of fluid. When you have extra fluid in this area, it’s hard to breathe.

Fluid may build up between your lungs and chest wall for any of these reasons:

  • A lung infection
  • Heart disease
  • A growth (tumor) 

Thoracentesis helps us diagnose the cause.

To perform this procedure, we first numb the area. We then insert a needle and a thin, flexible tube into the space to drain the excess fluid. The procedure usually takes 30 to 45 minutes.

Once we know what’s causing your fluid buildup, we may recommend further treatment.


Common causes of fluid buildup are infection, cancer, and heart disease. Other possible causes are:

  • Pneumonia
  • Tuberculosis
  • Blood clot in the lungs
  • Congestive heart failure
  • Liver disease
  • Kidney disease
  • Noncancerous tumor

Less common causes include:

  • Exposure to asbestos
  • Reaction to certain medications
  • Underlying health conditions (pancreatitis, thyroid diseases, and conditions that cause inflammation)

Therapeutic Thoracentesis

When fluid builds up between your lungs and chest wall, your lungs may not fully expand. This makes breathing difficult and painful. You might also have shortness of breath. This procedure can relieve these problems.

You may need routine (therapeutic) thoracentesis to remove regular fluid buildup. Certain long-term conditions (cancer and heart disease) can repeatedly cause fluid to build up in the space.


Thoracentesis is a safe procedure. Possible risks are:

  • Pain and bruising where we insert the needle.
  • Excessive bleeding or infection at the needle site.
  • Air leaking into the pleural space (pneumothorax), making it hard to breathe.
  • Trouble breathing (respiratory distress).
  • Fluid buildup in your lungs.

Rare complications include injury to the liver and spleen from the needle.

How to Prepare

You don’t need to do anything special to prepare for this procedure.

Before the procedure, it’s important to tell us:

  • About all medications, vitamins, and herbal supplements you take. We may ask you to stop taking blood thinners or other medications.
  • About any allergies to medicines or latex.
  • If you’re pregnant or plan to become pregnant.
  • If you had previous bleeding problems after surgery or other procedures.

We can safely perform this procedure:

  • At your bedside in the hospital.
  • In a radiology suite.
  • In our clinic.

What to Expect

The procedure usually takes 30 to 45 minutes. Removing high fluid volumes may take longer.

You’ll be awake and sitting with your arms and head resting on a table in front of you.

  • First, we numb the area with local anesthesia.
  • Next, we use ultrasound to find the fluid buildup.
  • After you’re numb, we carefully insert the needle into your back or side.
  • The needle is replaced with a thin plastic tube attached to a vacuum system that withdraws the fluid.

Be sure to tell us if you have shortness of breath or chest pain while we remove the fluid.

It’s extremely important not to move, cough, or breathe deeply during this part of the procedure. Let us know if you feel you can’t control these urges. 

After the procedure, you’ll be able to breathe easier. We’ll also take a chest X-ray to see how much fluid was removed.

Carefully follow all discharge instructions that you’re given after this procedure.


After the procedure we’ll:

  • Send a fluid sample to a laboratory to identify the cause of fluid buildup.
  • Know the results within 2 weeks, or earlier.

Once we know the cause, we can talk about your treatment plan together. For example, you may need antibiotics to treat a lung infection.

For more serious conditions (such as cancer or heart disease), we’ll talk about how best to treat your condition. It’s possible you might need routine removal of regular fluid buildup.

When to Call Us

Call us right away if you develop signs of infection, such as:

  • Redness, swelling, and tenderness around the needle site
  • Fever
  • Pain at the needle site

Call 911 or seek urgent care if you develop:

  • Shortness of breath
  • Sudden difficulty breathing

Additional References:

Related Health Tools:

Prepare for Your Procedure

If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following: (1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.

This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.