
Overview
This module describes how to perform thoracentesis, or a pleural tap, to drain fluid from a patient’s pleural space.
Indications
Contraindications
Patient information and consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“There is fluid in the space around your lung, which is pressing on the lung tissue and causing your shortness of breath. I need to draw off some of it.”
What can my patient expect?
“I will give you an injection for pain, then I will put a needle into the collection of fluid and allow it to drain by itself. It might take a while, and you will have to sit up, leaning forward, while it drains.”
What is my patient’s role?
“Let me know if you have any allergies or a bleeding tendency, or use blood thinners. Fearing blood or needles is normal, but tell me if you have fainted from it. Try to keep still while I do this procedure, and let me know if you feel any strange sensations or severe pain.”
Preparation

Documentation
Equipment
If conducting a diagnostic tap:
Site & Positioning
If possible, take a chest X-ray prior to this procedure.
Ask the patient to sit, bent over forward. Tuck a linen saver or paper towel into their pants, skirt or underwear.
Percuss to find the area of dullness on their back, and find a puncture site. Avoid the cardiac region, and do not puncture below the 9th rib or above the axillary crease. Often, the best site is the 8th intercostal space posterolaterally.

Procedure
Follow medical asepsis with sterile gloves.
Troubleshooting
I didn’t get back fluid on my first pass.
Don’t stop aspirating as you withdraw from the skin. Use a new IV cannula and try again in the adjacent space, ensuring that you have a big enough gauge cannula as specified above.
I did not get fluid back on my second pass.
Call a senior. If still unsuccessful, request a
lateral decubitus chest X-ray
The patient lies on their side for the X-ray (same side for effusions and opposite side for pneumothoraces). Can also distinguish between an effusion between the lungs and diaphragm, and intra-abdominal pathology. Explain on the radiography request form what you are looking for.
and check for
run off.
If the effusion is liquid and thus drain-able, it will 'run' along the pleura when the patient is placed on their side. When viewing the lateral decubitus you will see the fluid has tracked upwards along the pleura. If this does not happen and the fluid remains unchanged on the lateral decubitus view, it means the fluid is loculated or 'walled off'.
If no run off, the effusion may be loculated. This may need to be drained under ultrasound guidance.


Instead of fluid I got blood back.
If this is a tiny amount just filling the hub of the needle or cannula, continue as above. If there is a fair amount of venous blood filling the syringe, stop aspirating, withdraw the syringe and apply pressure to the site before attempting in the adjacent space.
Fluid was draining, but has stopped after only a small amount has drained.
The cannula may be kinked. Repeat the procedure using a new IV cannula. If the fluid is bloodstained, there may be a clot obstructing the cannula. Remove the administration set, check for a clot at the needle or cannula hub, and remove it. If unsuccessful, try again in an adjacent space.