Home » Notes » Nursing Fundamentals and Skills » Thoracentesis


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By Paul Martin, BSN, R.N.

Thoracentesis is a procedure in which a needle is inserted through the back of the chest wall into the pleural space (a space that exists between the two lungs and the anterior chest wall) to remove fluid or air. Pleural fluid analysis is the microscopic and chemical lab analysis of the fluid obtained during thoracentesis.

Table of Contents

What is Thoracentesis?

Thoracentesis, also known as pleural tap or pleural biopsy, involves the insertion of a needle or catheter into the pleural space to drain fluid or air buildup. It’s commonly performed under ultrasound guidance to ensure accuracy and safety.


Thoracentesis, a procedure to remove fluid or air from the pleural space, is indicated for various conditions where fluid or air accumulation compromises respiratory function or causes discomfort. Indications include:

1. For diagnostic purposes. For diagnostic purposes, thoracentesis is employed to evaluate conditions such as pleural effusion, empyema, hemothorax, chylothorax, and to differentiate between transudative and exudative effusions. By extracting and analyzing the pleural fluid, healthcare providers can identify the underlying cause of these conditions, which is crucial for determining appropriate treatment.

2. For therapeutic purposes. Therapeutically, thoracentesis is used to relieve symptoms such as dyspnea caused by large pleural effusions or pneumothorax. It is particularly beneficial in emergency situations, such as the decompression of a tension pneumothorax, where immediate intervention is required to prevent life-threatening complications. Additionally, thoracentesis may be performed preoperatively to optimize lung function, ensuring better surgical outcomes for patients undergoing thoracic surgery.


The following are needed when performing thoracentesis:

  • Sterile gloves and drapes
  • Local anesthetic (lidocaine)
  • Syringes and needles (for local anesthesia and specimen collection)
  • Thoracentesis kit (includes sterile drape, antiseptic solution, skin marker, scalpel or needle, thoracentesis needle or catheter, collection bottles or vacuum containers, connecting tubing, and dressing materials)
  • Ultrasound machine (optional but highly recommended for guidance)


Thoracentesis is a valuable procedure for diagnosing and managing pleural effusion and pneumothorax, but it requires careful preparation, skilled execution, and vigilant monitoring to ensure patient safety.

1. Position the patient sitting with arms and head resting on a bedside table.
If the patient is unable to sit, lie them on the affected side with the same side arm over the head. This position ensures access to the midaxillary line for needle insertion. Proper positioning allows optimal access to the pleural space and minimizes the risk of injury to surrounding structures.

2. Insert the thoracentesis needle in the posterolateral back, below the fluid level.
Confirm by counting ribs on x-ray and percussing for fluid level. Mark the top of dullness with washable ink or skin indentation. Accurate insertion below the fluid level and marking the site helps in targeting the correct location for fluid removal.

3. Select the thoracentesis site in an interspace below the point of dullness to percussion in the mid-posterior line (posterior insertion) or mid-axillary line (lateral insertion).
Choosing the correct interspace ensures that the needle enters the pleural space without damaging the lung tissue.

4. Use sterile technique, including gloves, betadine prep, and drapes.
Maintaining sterility prevents infection at the insertion site and in the pleural space.

5. Anesthetize the skin over the insertion site with 1% lidocaine using a 5 cc syringe with a 25 or 27-gauge needle.
Next, anesthetize the superior surface of the rib and the pleura. Proper anesthesia reduces patient discomfort and pain during the procedure.

6. Insert the needle over the top of the rib (superior margin) to avoid the intercostal nerves and blood vessels that run on the underside of the rib.
Avoiding the neurovascular bundle minimizes the risk of causing nerve damage or bleeding.

7. Insert the needle and aspirate to check for pleural fluid. Once fluid returns, mark the depth with a hemostat. Remove the anesthetizing needle. Aspirating confirms entry into the pleural space, and marking the depth ensures correct placement for subsequent steps.

8. Measure the depth on the thoracentesis needle with a hemostat.
Apply steady pressure on the patient’s back. Insert the needle through the anesthetized area at the same depth as the first needle. Measuring ensures consistent needle depth, improving accuracy and safety.

9. Advance the needle until it reaches the superior aspect of the rib.
Continue over the top of the rib through the pleura, maintaining gentle suction on the syringe. Ensure moving over the rib to avoid the neurovascular bundle below. Advancing the needle correctly helps prevent injury to the intercostal structures and ensures proper fluid extraction.

10. Attach the three-way stopcock and tubing, and aspirate the amount needed. Turn the stopcock and evacuate the fluid through the tubing.
Using the stopcock and tubing allows controlled fluid removal, minimizing the risk of rapid decompression and associated complications.

11. Withdraw the required pleural fluid (typically 100 mL for diagnostics), but avoid removing over 1500 mL at once.
This decreases the risks of pleural edema or hypotension. Controlled fluid removal prevents complications such as re-expansion pulmonary edema and hemodynamic instability.

12. Upon completion of fluid drainage, instruct the patient to take a deep breath and hum before gently removing the needle. This action elevates intrathoracic pressure, reducing the risk of pneumothorax. Cover the site with a sterile occlusive dressing. Increasing intrathoracic pressure during needle withdrawal helps prevent air entry into the pleural space, thereby reducing the risk of pneumothorax. A sterile dressing maintains site sterility and prevents infection.

Nursing Diagnosis

Here are some possible nursing diagnoses for a patient post-thoracentesis (you may also check on the nursing care plans for Pleural Effusion)

  1. Ineffective Breathing Pattern related to decreased lung volume capacity. This diagnosis focuses on the patient’s difficulty in maintaining effective breathing patterns due to reduced lung volume following the procedure.
  2. Impaired Gas Exchange related to alveolar-capillary membrane changes. This diagnosis addresses the patient’s potential difficulty in oxygenating blood and removing carbon dioxide due to alterations in the alveolar-capillary membrane.
  3. Impaired Skin Integrity related to mechanical factors secondary to thoracentesis and chest tube insertion. This diagnosis pertains to the risk of skin breakdown and infection at the procedure and chest tube sites.
  4. Acute Pain related to surgical incision, chest tube sites, and immobility. This diagnosis highlights the pain the patient may experience due to incisions, chest tube placement, and limited movement post-procedure.
  5. Impaired Physical Mobility. This diagnosis acknowledges the patient’s potential difficulty in moving and performing physical activities following thoracentesis and associated treatments.
  6. Activity Intolerance. This diagnosis addresses the patient’s reduced capacity to engage in physical activities due to pain, reduced lung function, and overall weakness post-procedure.

Nursing Interventions

Here are some nursing interventions and considerations for thoracentesis:

Before the Procedure

1. Verify physician’s order.
Confirming the doctor’s order for thoracentesis validates the procedure’s necessity and suitability for the patient’s condition, promoting accuracy and alignment with the treatment plan.

2. Explain the procedure, risks, and benefits to the patient and guardian.
Patient education promotes informed consent and helps alleviate anxiety, ensuring cooperation during the procedure.

3. Obtaining informed consent. Ensure the patient understands the procedure and its associated risks before signing the consent form.
Informed consent is essential for respecting patient autonomy and legal protection.

4. Inform that she will be experiencing mild pain on the site where the needle was pricked.
The mild pain is due to the penetration of the skin and underlying tissues. This is typically brief and can be managed with local anesthesia administered prior to the procedure.

5. Inform the client that the procedure takes only few minutes, depending primarily on the time it takes for fluid to drain from the pleural cavity.
The duration is mainly dependent on how quickly the fluid drains from the pleural cavity.

6. Inform the client not to cough while the needle is inserted.
Coughing can cause sudden movements that may interfere with the precise placement of the needle into the pleural space, increasing the risk of injury to surrounding structures and potentially complicating the procedure.

7. The patient may have a diagnostic procedure, such as a chest x-ray, chest fluoroscopy, ultrasound, or CT scan, performed before the procedure.
X-ray or ultrasound before thoracentesis helps locate the effusion accurately, ensuring safe needle placement and reducing the risk of injuring nearby structures. It provides real-time guidance, enhancing the precision and safety of the procedure.

8. Asked the patient to remove any clothing, jewelry, or other objects that may interfere with the procedure. The area around the puncture site may be shaved.
Patients are asked to remove clothing, jewelry, and other items to allow unobstructed access to the puncture site. Shaving the area helps maintain cleanliness and facilitates a sterile environment for the procedure.

9. Vital signs (heart rate, blood pressure, breathing rate, and oxygen level) are to be monitored before the procedure.
Vital signs before thoracentesis are checked to assess baseline health status and identify any potential risks or contraindications for the procedure.

During the Procedure

10. Vital signs (heart rate, blood pressure, breathing rate, and oxygen level) are to be monitored during the procedure.
Monitoring vital signs during thoracentesis allows early detection of any adverse reactions or complications, promoting patient safety throughout the procedure.

12. The patient may receive supplemental oxygen as needed, through a face mask or nasal cannula (tube).
This helps maintain adequate oxygenation throughout the procedure, especially for patients with compromised respiratory status.

13. Assist the patient into the appropriate position, usually sitting upright or lying on the unaffected side. Provide pillows or support to maintain comfort and stability during the procedure.
Proper positioning facilitates optimal access to the pleural space and enhances patient comfort and safety.

14. Hand instruments and supplies to the healthcare provider as needed. Maintain a sterile field throughout the procedure.
Collaboration with the healthcare provider ensures the safe and efficient performance of the procedure while minimizing the risk of infection or injury.

15. After the procedure, a small sterile dressing is placed over the site of the puncture.
Apply pressure to the puncture site and cover it with a sterile dressing to prevent air leakage and reduce the risk of infection.

After the Procedure

16. Observe the client for signs of distress, such as dyspnea, pallor, and chest pain.
Closely monitor the patient for signs of distress, including difficulty breathing, pale skin, and chest pain, as these may indicate complications such as pneumothorax or respiratory compromise. Prompt recognition of these symptoms allows for immediate intervention.

17. Assist the patient to lie on the unaffected side with the head of the bed elevated 30 degrees for at least 30 minutes.
This position facilitates lung expansion and promotes the reabsorption of any remaining pleural fluid, reducing the risk of fluid reaccumulation.

18. Document the procedure, including the amount of fluid or air drained, patient tolerance, any complications encountered, and post-procedure instructions given to the patient.
Accurate documentation ensures continuity of care, provides a clear medical record for future reference, and helps in assessing the treatment’s efficacy.

19. Label the obtained specimen with the patient’s name, date, time, and source, then send it to the laboratory for analysis. Properly labeled specimens are crucial for laboratory analysis to identify the underlying cause of the pleural effusion, guiding further treatment.

20. Monitor the patient’s blood pressure, pulse, and breathing until stable. Assess the dressing over the puncture site for bleeding or other drainage. Continuous monitoring of vital signs and the puncture site ensures prompt identification and management of any complications, such as bleeding or infection.

21. Inform the patient that normal activities can be resumed after 1 hour if no evidence of pneumothorax or other complications is present. The puncture site from thoracentesis typically heals quickly, allowing the patient to resume normal activities shortly after the procedure, provided there are no complications.

References and Source

Paul Martin R.N. brings his wealth of experience from five years as a medical-surgical nurse to his role as a nursing instructor and writer for Nurseslabs, where he shares his expertise in nursing management, emergency care, critical care, infection control, and public health to help students and nurses become the best version of themselves and elevate the nursing profession.

4 thoughts on “Thoracentesis”

  1. Hi Matt,
    This is a great reference and step by step notes on this procedure that is challenging to find info on.
    I was wondering if your recommendation/practice is to have the nurse with the patient during the WHOLE process? Or does the nurse assess the patient before and after?
    All the best,
    Nurse Liz

    • Hi Riwa, So glad to hear you’re finding it helpful, especially during your second year of GNM! 🎉 Nursing school can be intense, right? Out of curiosity, what’s been the most challenging topic for you so far? Maybe I can whip up some more content around that!


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