Last updated: June 9, 2023

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Summarytoggle arrow icon

Thoracentesis is a procedure that removes pleural fluid for diagnostic and/or therapeutic purposes. It is used to relieve symptoms (e.g., dyspnea) and/or obtain pleural fluid for analysis to help determine the underlying cause (e.g., infection, malignancy). Relative contraindications include coagulopathy and infection over the procedure site. It is important to determine the best puncture site using ultrasound guidance and ensure all necessary equipment is at the bedside before performing the procedure. Complications include reexpansion pulmonary edema and pneumothorax.

See also “Pleural effusion.”

Definitiontoggle arrow icon

Indicationstoggle arrow icon

Patients with conditions known to cause bilateral symmetrical pleural effusions (e.g., heart failure, cirrhosis, ESRD) typically do not require a confirmatory diagnostic thoracentesis.

Contraindicationstoggle arrow icon

Pleural fluid drainage with chest tube insertion, surgery, or indwelling pleural catheter implantation is preferable for certain patients and underlying etiologies (see “Pleural effusion treatment” for details).

We list the most important contraindications. The selection is not exhaustive.

Technical backgroundtoggle arrow icon

Landmarks and positioningtoggle arrow icon

  • Place the patient in the sitting position with their arms resting on the bedside table.
  • Determine the puncture site using ultrasound and mark the skin.

Preparationtoggle arrow icon

Equipment checklisttoggle arrow icon

Procedure/applicationtoggle arrow icon

Puncture of the intrapleural space

  1. Administer single-point local anesthesia along the anticipated needle tract.
  2. Assemble the appropriate needle and syringe for the procedure.
  3. Insert the needle at the anesthetized puncture site under ultrasound guidance.
  4. Maintain negative pressure on the syringe and advance until fluid returns.
  5. Once position is confirmed, continue with diagnostic thoracentesis steps or therapeutic thoracentesis steps as indicated.
  6. Once fluid removal is complete, withdraw the needle as the patient exhales and apply an occlusive dressing.

Diagnostic thoracentesis steps [3]

  1. Attach the thoracentesis needle to a 60 mL syringe.
  2. Follow steps to puncture the intrapleural space.
  3. Once proper needle position is confirmed, collect 50 mL of pleural fluid.

Therapeutic thoracentesis steps [3]

  1. Attach the over-the-needle assembly to a 10 mL syringe.
  2. Follow steps to puncture the intrapleural space.
  3. Once proper needle position is confirmed, advance the catheter over the needle into the pleural space.
  4. Remove the needle and attach a three-way stopcock to the catheter hub.
  5. Connect high-pressure tubing to the three-way stopcock.
  6. Attach the tubing to a drainage bag or evacuated container.
  7. Allow drainage of a maximum of 1500 mL of pleural fluid.
  8. Stop drainage if the patient develops a cough, chest discomfort, or hypoxia. [6]

Avoid draining more than 1500 mL of pleural fluid, as it is associated with a higher risk of reexpansion pulmonary edema. [3]

Pitfalls and troubleshootingtoggle arrow icon

Pitfalls and troubleshooting during thoracentesis [3][4][7]
Complication Prevention and screening Management
Vascular injury and hemothorax
  • Consider screening coagulation panel prior to the procedure.
  • Maintain proper positioning, landmarking, ultrasound guidance, and negative pressure in the syringe during puncture.
  • Guide needles along the superior rib edge to avoid intercostal neurovascular bundles.
Infection and empyema
  • Obtain postprocedure CXR if suspected clinically.
  • Maintain proper positioning, landmarking, ultrasound guidance, and negative pressure in the syringe during the puncture.
Reexpansion pulmonary edema

Postprocedure checklisttoggle arrow icon

Postprocedure CXR is not routinely recommended in asymptomatic patients with uncomplicated thoracentesis. [8][9]

Interpretation/findingstoggle arrow icon

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Referencestoggle arrow icon

  1. $Contributor Disclosures - Thoracentesis. All of the relevant financial relationships listed for the following individuals have been mitigated: Alexandra Willis (copyeditor, was previously employed by OPEN Health Communications). None of the other individuals in control of the content for this article reported relevant financial relationships with ineligible companies. For details, please review our full conflict of interest (COI) policy.
  2. Saguil A, Wyrick K, Hallgren J. Diagnostic approach to pleural effusion.. Am Fam Physician. 2014; 90 (2): p.99-104.
  3. Roberts JR. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. Elsevier ; 2018
  4. Walls R, Hockberger R, Gausche-Hill M. Rosen's Emergency Medicine. Elsevier Health Sciences ; 2018
  5. Kasmani R, Irani F, Okoli K, Mahajan V. Re-expansion pulmonary edema following thoracentesis. Can Med Assoc J. 2010; 182 (18): p.2000-2002.doi: 10.1503/cmaj.090672 . | Open in Read by QxMD
  6. Verhagen M, van Buijtenen JM, Geeraedts LMG. Reexpansion pulmonary edema after chest drainage for pneumothorax: A case report and literature overview. Respiratory Medicine Case Reports. 2015; 14: p.10-12.doi: 10.1016/j.rmcr.2014.10.002 . | Open in Read by QxMD
  7. Petersen WG, Zimmerman R. Limited Utility of Chest Radiograph After Thoracentesis. Chest. 2000; 117 (4): p.1038-1042.doi: 10.1378/chest.117.4.1038 . | Open in Read by QxMD
  8. Lenaeus MJ, Shepherd A, White AA. Routine Chest Radiographs after Uncomplicated Thoracentesis. J Hosp Med. 2018; 13 (11): p.787-789.doi: 10.12788/jhm.3042 . | Open in Read by QxMD
  9. Williams JG, Lerner AD. Managing complications of pleural procedures. J Thorac Dis. 2021; 13 (8): p.5242-5250.doi: 10.21037/jtd-2019-ipicu-04 . | Open in Read by QxMD
  10. Porcel JM. Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists. Tuberc Respir Dis (Seoul). 2018; 81 (2): p.106.doi: 10.4046/trd.2017.0107 . | Open in Read by QxMD

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