At a thoracentesis is pierced with a sterile puncture needle into the pleural space - the small space between the lung and pleura. For example, accumulated fluid (pleural effusion) can be removed or even be collected for analysis. The procedure is performed under local anesthesia on the seated (rarely lying) patient. Read all important information about the pleural function here!


  • What is a pleural function?
  • When do you perform a pleural function?
  • What do you do with a pleural function?
  • What are the risks of a pleural function?
  • What should I pay attention to after a pleural function?

What is a pleural function?

The pleural function removes an effusion (fluid accumulation) from the narrow gap between the two pleura leaves: the lung pleura (pleura visceralis), which lies directly on the lungs, and the pleura (parietal pleura), which rests against the rib cage wall. Causes of a pleural effusion may be various diseases and injuries; some examples:

Inflammation, such as pleurisy, can cause effusion with several liters of fluid, causing severe respiratory distress.

Tumors can also lead to a pleural effusion, which then necessitates a pleural puncture. This applies both to tumors directly in the region of the lungs or the immediate environment as well as to metastases of distant tumors.

Heart failure (heart failure) relatively often causes a pleural effusion. With only small amounts of fluid sometimes no pleural puncture is necessary, because the effusion is often absorbed by the tissue after switching the medication.

Breast injuries (such as rib fractures) can lead to bloody pleural effusion (hematothorax). If the injury leads to a rupture of the largest lymphatic vessel of the body (thoracic duct) in the chest area, this results in a lymph-containing pleural effusion (chylothorax).

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When do you perform a pleural function?

For therapeutic reasons, a pleural function is performed when in the space between the two pleura leaves so much fluid has accumulated that it displaces the lungs and thus causes the patient breathlessness. Sometimes a pleural puncture is also performed for emergency relief of pressure in a pneumothorax, ie when air has entered the pleural space, so that the negative pressure prevailing here is lost. This can happen, for example, in injuries in the incubator area (puncture or gunshot wounds, broken ribs, etc.) or various illnesses (such as COPD). The following diseases often accumulate fluid in the pleural space:

  • Heart failure
  • Protein deficiency in the blood, both in malnutrition and in certain kidney diseases
  • lung infection
  • tuberculosis
  • Lung cancer or breast cancer
  • purulent inflammation (pleural empyema)
  • Bruising after a rib fracture or a lung crush, after accidents or falls (hematothorax)

Rarely, a pleural puncture is performed for diagnostic reasons alone, when the cause of an effusion is unclear. The obtained liquid sample can be examined more precisely in the laboratory, for example on bacteria, inflammatory cells or cancer cells.

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What do you do with a pleural function?

Before the pleural function, the doctor will check the pleural effusion by ultrasound to estimate the approximate amount and possible puncture site. A blood sample provides information on whether the patient is suffering from a coagulation disorder, in order to prevent later complications such as heavy bleeding.

In order for the effusion to collect completely in the region of the diaphragm, the patient sits at the pleural puncture. If patients are restricted in their movements, a pleural puncture is possible even while lying down. Basically, the doctor chooses the lowest possible puncture site to be able to aspirate a lot of liquid.

First, the doctor disinfects the puncture site, surrounds it with a sterile drape and injects a local anesthetic, so that no pain is felt during the puncture. A general anesthetic is not necessary, but anxious patients may be given a drug for reassurance.

As soon as the anesthetic is completely effective, the doctor asks the patient to inhale and exhale deeply and then to hold their breath. Now he pushes the cannula through the skin and musculature through the ribs. It is important to pierce the cannula at the upper edge of a rib so as not to injure nerves and blood vessels.

After a few centimeters, the needle is in the pleural space: The liquid can now be sucked off with the help of a syringe. Then the doctor pulls the syringe out again - the wound usually closes itself and is covered with a wound plaster.

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What are the risks of a pleural function?

In rare cases the following complications may occur with the pleural puncture:

  • Bleeding in the area of ​​the puncture site (especially in unrecognized coagulation disorders)
  • infections
  • Injury of adjacent organs or tissue structures (such as lung, diaphragm, liver, spleen)
  • Pulmonary edema and possibly a renewed pleural effusion (if the effusion is sucked off too quickly, so that a negative pressure develops in the pleural space)