What Is a Thoracentesis (Pleurocentesis)?

A thoracentesis, also known as a pleurocentesis, is a minimally invasive procedure that removes fluid buildup from the pleural cavity using a hollow needle.

When mesothelioma causes fluid to build up between the two layers of the pleural lining around the lungs, it can lead to cough, chest pain, discomfort and breathing difficulties.

This condition is called a pleural effusion. It is healthy to have a small amount of fluid in the pleura, but when excess fluid buildup puts pressure on one or both lungs, removing the fluid through a thoracentesis procedure is the simplest way to give the patient relief.

Thoracentesis Facts

  • Involves removing pleural fluid buildup through a hollow needle.
  • Used to treat and help diagnose the cause of pleural effusions.
  • Less permanent solution than pleurodesis procedure or catheter insertion.
  • Less invasive palliative treatment option for late-stage mesothelioma patients.

Thoracentesis is also referred to as “pleural fluid aspiration,” “pleural tap,” “pleurocentesis” and “thoracocentesis.”

A chest X-ray can reveal a pleural effusion but usually not the reason for it. Because many different diseases can cause pleural effusions, doctors examine the fluid collected through thoracentesis to try to identify the root cause. However, thoracentesis testing is generally not reliable enough to confirm a mesothelioma diagnosis, which usually depends on analyzing a cancer tissue sample collected through a biopsy.

Palliative Thoracentesis Versus Other Treatments

Palliative therapies for pleural mesothelioma aim to relieve painful symptoms and improve a patient’s quality of life, rather than attempting to cure the cancer. Removing excess pleural fluid alleviates chest pain and shortness of breath by reducing pressure on the chest and lungs and providing more space for the lungs to expand during respiration.

Thoracentesis has become less common as a mesothelioma treatment compared to other procedures:

  • Many mesothelioma patients benefit more from pleurodesis, which drains excess fluid and then seals the pleural space to prevent fluid from building up there again.
  • Another option is for doctors to insert a catheter, such as an indwelling pleural catheter, or IPC, that continuously drains the pleura so the patient does not have to undergo repeated thoracentesis procedures.
  • Mesothelioma patients who have early-stage cancer and are in otherwise good health may be eligible for a more aggressive surgery that removes the diseased part of the pleura altogether.

However, for patients too weak to withstand one of these options, or who wish to avoid a hospital stay, the less invasive thoracentesis procedure remains a tried-and-true technique for alleviating the symptoms caused by a pleural effusion.

A 2021 study recorded the outcomes of 16 patients who underwent thoracentesis. After the procedure, breathlessness, chest pain and cough improved in some patients. They reported feeling and sleeping better, but fatigue and poor appetite remained. Participants were more active after aspiration, and many felt the procedure was worthwhile.

Surgical Consultation for Thoracentesis

A thoracentesis requires a surgical consultation even though it is considered a minimally invasive procedure. During the consultation, patients meet with the surgeon to learn more about the procedure and find out if they qualify. The surgeon will thoroughly review their medical records, imaging scans and biopsy results to determine if they are eligible.

Consultations give patients the chance to meet with the surgeon in person or virtually through video conferencing. Patients may ask questions, bring up any concerns they have and get to know the surgeon and their history of success with the procedure. The surgeon or a member of the surgical staff will let patients know what they need to do to prepare for surgery, how the procedure will go and what recovery will look like.  

Brigham and Women's Hospital and the Lung Institute at Baylor College of Medicine
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What to Expect During a Thoracentesis Procedure

The patient may assume a seated position throughout the procedure or lie down if necessary. The doctor sterilizes the skin around the insertion point and provides local anesthesia to numb the area.

Next, the doctor inserts a long, hollow needle called a cannula between the ribs, guided by ultrasound or CT scan images. The patient may experience a feeling of pressure, but the anesthesia usually blocks any pain. Once the needle is inserted, the doctor drains the pleural effusion until some or all of the fluid is removed, depending on the goal of the thoracentesis. The entire process takes about 15 minutes.

The doctor usually sends the extracted fluid to a lab for analysis (pleural cytology). After removing the needle and dressing the wound, the doctor often orders a chest X-ray as well to confirm enough fluid was removed and to ensure there is no sign of a collapsed lung.

Risks and Complications

While complications are rare, they can occur. The most common serious complication of the procedure is a collapsed lung, also known as pneumothorax. This can happen if the doctor accidentally punctures the lung or disrupts an accumulation of air in the pleural cavity.

Other possible complications include:

  • Bleeding (generally from injury to an intercostal vessel)
  • Pain
  • Infection
  • Diaphragm injury
  • Laceration to lung, spleen or liver
  • Tumor seeding (invasion of cancer cells along the needle track)

Complications are more common among certain groups of patients. Patients with a history of lung surgery face greater risks, as do patients with a chronic, irreversible lung disease such as asthma or emphysema. Patients with any condition that affects normal blood clotting may also face a higher risk of complications.

One 2010 study identified patients who would benefit most from thoracentesis while experiencing the lowest risk of complications. Out of 446 patients involved in the study, including a number of malignant mesothelioma patients, the incidence of pneumothorax was significantly lower in patients whose procedure was guided by an ultrasound.

Another factor that increased the risk of complications in participants was the presence of symptoms of their primary disease. Thoracentesis led to complications for only one asymptomatic patient (out of 328 total), yet 15 of 118 symptomatic patients developed complications.