Pleural aspiration (thoracocentesis)

Pleural aspiration (also known as thoracocentesis) is the aspiration of fluid from the pleural space (pleural effusion). All pleural procedures should be performed under real-time ultrasound guidance

Indications for pleural aspiration (thoracocentesis)

• To aid the diagnosis of a unilateral, suspected exudative pleural effusion
• To exclude empyema as this requires urgent intercostal drainage

 Equipment required for pleural aspiration (thoracocentesis)

• Ultrasound machine and an operator who is at least level one competent at pleural ultrasound
• Sterile ultrasound probe cover
• Sterile gloves
• Sterile field and dressing
• Chlorhexidine cleaning solution
• Lignocaine
  • Remember 3mg/kg is the maximum safe dose
    • 5mls of 2% preparation contains 100mg lignoicaine. The max dose for a 70kg person is therefore approximately 10mls 2% lignocaine.
• 50ml syringe and green needle

 Contraindications to pleural aspiration (thoracocentesis)

• Coagulopathy
• Lack of ultrasound support
• Local infection
• Very small fluid volume

 Pre-procedure:

• Consent the patient
  • Ideally written consent should be gained
  • Consent for pain, bleeding, infection, damage to surrounding structures (including pneumothorax with subsequent drain) and failure.
• Review chest x-ray and examine patient to confirm side of insertion
• Set up an aseptic trolley with equipment
• Perform a provisional ultrasound

 Procedure for pleural aspiration (thoracocentesis)

• Don sterile gloves

• Clean the area identified for aspiration and apply a sterile field
• Further ultrasound can be conducted with the probe in a sterile sheath
• Infiltrate 5-10ml of lignocaine initially under the skin and then into the subcutaneous tissue and then pleural space
  • Start with an orange needle, then a blue needle and then green.
• You should be able to access the pleural space with the green needle
• Allow time for lignocaine to act
• Using a green needle and 50ml syringe insert the needle along the tract used for the local anaesthetic. Aspirate as you insert the needle until fluid is aspirated.
• Aspirate 10-30ml of fluid
• Withdraw needle
• Dress insertion area with a sterile dressing

Training video on the use of ultrasound in pleural aspiration

 Post-procedure care:

• Analgesia if required.
• Send fluid for:
  • Cytology, MC&S, LDH, Protein
  • pH (put some fluid in an ABG syringe and run through the ANG machine if necessary)
  • Consider TB culture (acid-fast bacilli) if clinically indicated
  • Consider glucose or cholesterol (if concerned about chylothorax)
• Send serum blood samples for LDH and protein.
• Post procedure chest x-ray to ensure no pneumothorax.
• Ensure nursing staff are aware procedure has occurred do they can monitor more regularly.

 In the event of failure of pleural aspiration (thoracocentesis)

• Stop procedure.
• Seek senior help.
• Re-review imaging and patient with a senior colleague to ensure presence of fluid.
• Consider further imaging or aspiration in radiology.

 Top tips for pleural aspiration (thoracocentesis)

• Send the largest sample to cytology
  • The more fluid that the lab receive the higher the diagnostic yield.
• Explain that is a pneumothorax does occur that the patient will then require a chest drain.
• If you diagnose an empyema on fluid pH (pH < 7.2) you must arrange for an intercostal chest drain to be inserted immediately.

Click here to download free teaching notes on pleural aspiration: Prodecures – Pleural aspiration

Perfect revision for medical students, finals, OSCEs and MRCP PACES