Thoracentesis: indication,procedure and complications

What is thoracentesis?

Thoracentesis is a medical procedure used to remove excess fluid or air from the space between the lungs and the chest wall, known as the pleural space. This procedure is typically performed to relieve symptoms caused by pleural effusion (excess fluid) or pneumothorax (excess air) and to help diagnose the underlying cause of these conditions.

what is thoracentesis
what is thoracentesis

During a thoracentesis, a healthcare provider inserts a hollow needle or a small catheter through the skin and into the pleural space. The fluid or air is then withdrawn, and the needle or catheter is removed. The procedure is often guided by ultrasound imaging to ensure accurate placement and minimize the risk of complications.

Thoracentesis is indicated for a variety of conditions that result in the accumulation of fluid or air in the pleural space. Some of these conditions include:

  1. Pleural Effusion: Excess fluid in the pleural space can be caused by several factors, including heart failure, liver disease, kidney disease, lung infections (such as pneumonia), tuberculosis, cancer (metastases or pleural mesothelioma), and autoimmune diseases.
  2. Pneumothorax: This occurs when air leaks into the pleural space, causing the lung to collapse partially or completely. Thoracentesis can be used to remove the air and help the lung re-expand.
  3. Chylothorax: A rare condition where lymphatic fluid (chyle) accumulates in the pleural space, often due to trauma or surgery that disrupts the lymphatic system.A study from the Journal of Vascular Surgery suggests that the preferred treatment for Chylothorax is conservative management, including dietary restrictions and parenteral nutrition. If conservative treatment fails, Thoracentesis or thoracoscopic drainage may be considered.
  4. Hemothorax: Accumulation of blood in the pleural space, usually due to injury or trauma.
  5. Empyema: A condition where pus accumulates in the pleural space, typically as a complication of pneumonia or following thoracic surgery.
  6. Pleural Effusions in Cancer Patients: Cancer cells can metastasize to the pleura, leading to malignant pleural effusions. Thoracentesis can provide symptomatic relief and may be used for diagnostic purposes to identify the presence of cancer cells (such as lung cancer).

Thoracentesis is also performed for diagnostic purposes to analyze the fluid for cellular composition, pH, protein levels, glucose, and to identify microorganisms or malignant cells, which can help determine the underlying cause of the pleural effusion.

Thoracentesis is indicated for a variety of conditions
Thoracentesis is indicated for a variety of conditions

Thoracentesis procedure:

  1. Preparation: The patient is positioned seated and supported at a table or on the edge of the bed, with their arms supported on an over-the-bed table. The site where the needle will be inserted is cleaned and sterilized. An ultrasound may be used to locate the best insertion site and to guide the procedure.
  2. Numbing the Area: Local anesthesia is administered to numb the skin and deeper tissues at the insertion site. This ensures that the patient feels minimal discomfort during the procedure.
  3. Insertion of the Needle: A thin, hollow needle is inserted through the skin and into the pleural space. The healthcare provider may use ultrasound guidance to direct the needle to the correct location. Once the needle is in the pleural space, a syringe may be attached to withdraw the fluid.
  4. Fluid Withdrawal: If a syringe is used, the fluid is withdrawn manually. In other cases, a small catheter may be inserted through the needle, and the fluid may be drained into a collection bottle or bag. The amount of fluid withdrawn is carefully monitored to avoid removing too much, which could cause the lung to collapse.
  5. Monitoring: During the procedure, the patient’s vital signs, such as blood pressure, heart rate, and oxygen levels, are monitored to ensure their safety. The patient may be asked to stop breathing briefly during the insertion of the needle to minimize the risk of lung puncture.
  6. Completion of the Procedure: Once the desired amount of fluid has been removed, or if air was the target, the needle or catheter is removed. The insertion site is cleaned, and a bandage is applied.
  7. Post-procedure Care: The patient is monitored for a short period after the procedure to check for any signs of complications, such as pneumothorax. They may be given instructions on activity restrictions and when to follow up with their healthcare provider.

Thoracentesis is generally a well-tolerated procedure, and most patients experience relief of symptoms such as shortness of breath following the removal of excess fluid or air from the pleural space.

Thoracentesis procedure
Thoracentesis procedure


Thoracentesis is generally considered a safe procedure, but like any medical intervention, it does carry some risks and potential complications. Common complications include:

  1. Pneumothorax: This occurs when air leaks into the pleural space, causing the lung to collapse partially or completely. It is the most common complication of thoracentesis and may require additional procedures or chest tube insertion to resolve.
  2. Bleeding: There is a risk of bleeding at the site where the needle is inserted. This can lead to a small hematoma, which is a collection of blood under the skin.
  3. Infection: Although the procedure is performed under sterile conditions, there is still a risk of infection at the site of needle insertion or in the pleural space itself.
  4. Reactivation of tuberculosis: If the thoracentesis is performed on a patient with a history of tuberculosis that has become dormant, the procedure may reactivate the infection.
  5. Respiratory distress: Some patients may experience difficulty breathing or chest pain following the procedure, which may be due to various causes, including pneumothorax, infection, or re-expansion pulmonary edema.
  6. Pain: Temporary pain at the site of the needle insertion is possible. This usually resolves quickly but can be managed with pain medication if necessary.
  7. Hypoxemia: A decrease in oxygen levels in the blood can occur due to various reasons, including pneumothorax or retraction of the lung.
  8. Recurrent pleural effusion: In some cases, the fluid may reaccumulate in the pleural space, requiring repeat thoracentesis or other treatments.

Most complications are minor and can be managed promptly by healthcare professionals. The risk of complications can often be minimized by using ultrasound guidance for the procedure, which helps to visualize the pleural space and avoid injury to the lung. Following the procedure, patients should be aware of the signs of potential complications and report any concerns to their healthcare provider.

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