protocol for thoracocentesis

Last reviewed 08/2021

The site of the thoracocentesis is determined by:

  • radiographic appearances
  • percussion of the fluid level:
    • the optimal site is 1-2 intercostal spaces below the fluid level
  • thoracocentesis should not be performed lower than the 8th intercostal space

The area is cleaned and a sterile field is created. The skin is infiltrated with local anaesthetic using a 25-gauge needle. Deeper infiltration is with a 20-gauge needle. Frequent aspiration and avoidance of the vascular bundle on the inferior surface of the ribs prevents intravascular infusion of the local anaesthetic.

The thoracocentesis is performed by gradually "walking" over the top of the rib with the needle until the parietal pleura is pierced. The effusion is sampled.

An effusion may be drained by inserting a catheter in a similar manner. Connection of the catheter to a vacuum bottle achieves rapid drainage.