What is the technique of thoracentesis?

The thoracentesis is a percutaneous procedure in which a needle or catheter is inserted into the pleural cavity to extract fluid or air for diagnostic or therapeutic purposes.
The presence of pleural effusion is usually detected by physical examination and confirmed by chest x-ray.
The therapeutic thoracentesis is performed to reduce respiratory distress or hemodynamic instability due to thoracic compression.
There are absolute contraindications to thoracentesis, such as active infection at the puncture site.