emDocs - February 10, 2020 - Authors: Peta N and Avila J
Reviewed by: Montrief T; Koyfman A; Long B
"Pearls
- A diagnostic thoracentesis can be performed in patients with new pleural effusions or in patients with known but worsening pleural effusions.
- A therapeutic thoracentesis should be performed in unstable patients, patients with complicated parapneumonic effusions, or in patients with empyemas.
- Listen to your patients during the thoracentesis; if they complain of chest discomfort or worsening dyspnea… stop the procedure.
Pitfalls
- Typically, you should not drain more than 1 liter of fluid. Draining more than 1 liter of fluid can cause re-expansion pulmonary edema (patient becomes unstable and has frothy sputum).
- Your patient develops a cough during the thoracentesis. Should you be worried? Not really. This cough is probably a sign of physiologic lung re-expansion or pleural irritation from the tube.
Take Home Points
- There are a lot of causes for pleural effusions, but CHF is the most common precipitant seen in patients with bilateral pleural effusions. Malignancy is the most common cause of unilateral pleural effusions.
- You may not be able see a pleural effusion on a CXR unless there is at least 175mL of fluid present.
- If the effusion’s fluid is > 1.5cm in thickness (from parietal to visceral pleura) and covers at least 3 rib spaces, then it may be safe to tap.
- A great guide on thoracentesis, using ultrasound, can be found here: http://www.emdocs.net/ultrasound-guided-thoracentesis/
- Use an ultrasound to locate the effusion and decrease the risk of bleeding complications and pneumothorax.
- Patients with parapneumonic effusions or hemodynamic instability will need prompt initiation of antibiotics and a tube thoracostomy"