Critical Care Medicine-Pulmonary Disorders>>>>>Respiratory Diagnostic Modalities and Monitoring
Question 5#

You are the sole intensivist at a rural hospital, and the overnight hospitalist asked you to evaluate a patient with a left-sided malignant pleural effusion who is experiencing dyspnea. You determine that the patient has a very large pleural effusion, and you decide that a thoracentesis will be needed. Under ultrasound guidance, you place a chest tube and begin to aspirate the pleural effusion.

At what point should you stop your thoracentesis to maximize your drainage and minimize complication(s)?

A. Stop after draining 1 L of pleural effusion
B. Stop after patient complains of chest discomfort
C. Stop after your pleural manometer goes below −20 cm H2O
D. Stop after patient coughs

Correct Answer is B


Correct Answer: B

Re-expansion pulmonary edema (RPE) can be a life-threatening complication during thoracentesis for pleural effusion. Some evidence suggests that RPE occurs due to the sudden decrease in pleural pressure. It had been recommended to stop thoracentesis when pleural pressure dropped below −20 cm H2O (answer C) or when more than 1 L of fluid was removed (answer A). However, various studies have shown that large volume thoracentesis (more than 1 L) can be performed without adverse events, even if the final pleural pressure is below −20 cm H2O. In addition, further investigation show that there is little change in pleural pressure when the patient coughs, so coughing should not be an end point for thoracentesis (answer D). However, chest discomfort is recommended as the point at which thoracentesis would be stopped, due to the potential of development of unsafe negative pressure (answer B).


  1. Grabczak EM, Krenke R, Zielinska-Krawczyk M, Light RW. Pleural manometry in patients with pleural diseases – the usefulness in clinical practice. Respir Med. 2018. pii:S0954-6111(18)30023-4. doi:10.1016/j.rmed.2018.01.014.
  2. Feller-Kopman D, Walkey A, Berkowitz D, Ernst A. The relationship of pleural pressure to symptom development during therapeutic thoracentesis. Chest. 2006;129(6):1556-1560.