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CDHB

Chest Aspiration

Diagnostic pleurocentesis may be undertaken by medical staff with appropriate experience. You must see at least one performed and then do one yourself under supervision before attempting a chest aspiration on your own. If you are uncertain about whether to carry out a chest aspiration, contact the Respiratory Team on call.

Diagnostic Pleurocentesis - Method

• Explain the procedure to the patient. The only common complication is pneumothorax which occurs in approximately 5%. Obtain verbal consent and document in the clinical notes. It is essential to have the assistance of a nurse when performing a chest aspiration.
• Obtain the most recent chest X-ray.
• A lateral decubitus CXR will allow identification of free fluid. Pleurocentesis may be performed safely if 10 mm width free fluid is identified on a lateral decubitus CXR. However an USS is preferred pre aspiration and is essential if loculated fluid is suspected.
• Position the patient in an upright position, with arms and head resting forward on a pillow, exposing the posterior chest.
• Using percussion and vocal resonance, locate the upper limit of the effusion, and the area of maximal dullness overlying the known location of the effusion. If ultrasound (USS) has been performed, the area of maximal fluid should have been marked with an indelible pen. Always position the patient in the same way as for the USS.
• Using aseptic technique:
  • Infiltrate with local anaesthetic (1% lignocaine), then using a 20 mL syringe with a 22G, 38 mm needle, enter the pleural space by progressively advancing while aspirating. This needle is usually of sufficient length to reach the pleural space.
  • Aspirate 20 mL of pleural fluid. Stop the procedure if you aspirate air or the patient develops pain or coughing. If this occurs, withdraw the needle immediately and arrange urgent CXR.
  • Remove the syringe and needle then cover the puncture site with simple adhesive dressing.
  • Put three equal specimens into sterile pottles. Put 2 mL into an ABG syringe and cap it with a bung. The syringe will need to be sent directly to the laboratory for assessment of pH. The specimens will need to be processed immediately.
    Refer to Pleural Effusion for advice on which tests to do on the pleural fluid obtained.

Note - when to use ultrasound:

• Ultrasound is preferred for all patients. However it is essential if the effusion is difficult to locate by clinical examination, or if it appears to be loculated.
• If you are unable to obtain fluid with a 22G 38 mm needle, seek Respiratory Service advice before proceeding. It is unwise to use a longer or larger gauge needle without further imaging.

Therapeutic Pleurocentesis - Method

Explain the procedure to the patient. The most common complication is pneumothorax. Obtain verbal consent and document in the clinical notes.

• Follow the same initial steps as described in Diagnostic Pleurocentesis. A local anaesthetic should be used.
• Insert a 14 - 16 G 50 mm intravenous cannula into the pleural space. Following partial removal of the needle (to prevent lung puncture), the catheter should be advanced and secured. The catheter should be held at all times during the procedure.
• The needle should be removed, and the catheter attached to a giving set. The distal end of the giving set is attached to a catheter bag, which is placed on the floor. The giving set clamp should then be released and the fluid allowed to flow freely into the bag. Sometimes fluid does not immediately flow, in which case a 50 mL syringe with 20G needle should be put into the rubber giving port in the giving set, and 50 mL aspirated. This will allow flow to start, in a siphoning fashion.
• Aspiration should be stopped when:
  • 1000 - 2000 mL has been removed, depending on the patient's size. Removal of greater than this quantity in one sitting risks re-expansion pulmonary oedema.
  • The patient feels new chest discomfort or persistent coughing, indicating mediastinal shift.
• Repeat chest X-ray to check for pneumothorax.

Note: It is essential in both diagnostic and therapeutic pleurocentesis that the time and date of the procedure, the volume of fluid removed and any difficulties experienced are written in the clinical notes.

Topic Code: 1283