Unilateral pleural effusion - Investigation and management of a

Publication: 17/04/2019  
Next review: 07/01/2025  
Standard Operating Procedure
ID: 5964 
Supported by: Respiratory Dept
Approved By:  
Copyright© Leeds Teaching Hospitals NHS Trust 2022  


This Standard Operating Procedure is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Investigation and management of a unilateral pleural effusion


Pleural effusions result from an accumulation of pleural fluid in the pleural space. There are many reasons for this to happen, being divided into conditions that cause exudates (e.g. malignancy or infection) and transudates (e.g. CCF or hypoproteinaemia).
The initial step in investigating a pleural effusion is to ascertain whether this is a transudate or an exudate.

The fluid is an exudate if one or more of the following criteria are met…

  • Pleural fluid protein divided by serum protein is >0.5
  • Pleural fluid LDH divided by serum LDH is > 0.6
  • Pleural fluid LDH is > â…” the upper limits of normal serum LDH

Any unilateral pleural effusion should be investigated.
Bilateral effusions should be investigated if the clinical setting does not suggest a condition suggestive of generating pleural transudates of if there are atypical features or a lack of response to treatment.

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Flow chart for investigation and treatment

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Diagnostic aspiration of fluid

Operator or supervisor must be competent in procedure.
This ideally should not be done out of hours unless an empyema is suspected

Ultrasound should be used to guide optimum aspiration site

  1. Explain the procedure to the patient, including small risk of inducing pneumothorax and document written consent.
  2. Lean patient over a table
  3. The use of ultrasound is recommended to locate fluid (and assess for loculation). Try to aspirate near to the post axillary line/triangle of safety as more medially posteriorly the intercostal artery dips down into the intercostal space.
  4. Mark the appropriate side and site. Sterilise the area with cleaning fluid and infiltrate the skin and subcutaneous tissues to the pleura with lignocaine.
  5. When the pleural space is reached you should be able to aspirate fluid; you usually can do this with a green (21G) needle but occasionally will need a longer (spinal) needle depending on patient’s body habitus.
  6. Using a separate needle and 50ml syringe aspirate the fluid.
  7. If you cannot aspirate fluid you should proceed no further and should discuss with radiology about a ‘real-time’ ultrasound guided tap in the Radiology department.
  8. Fluid should be sent for
    • Biochemistry - Protein, LDH, glucose, pH in heparinised syringe
    • Bacteriology – both in sterile vials for C and S and AAFB and blood culture bottles C and S. (Please note the sensitivity for diagnosing TB from pleural fluid is low and a pleural biopsy in saline may be required).
    • Cytology

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Therapeutic aspiration of fluid

Operator or supervisor must be competent in procedure.
This should not be done out of hours unless required to alleviate significant breathless in the presence of a large pleural effusion
Ultrasound should be used to guide optimum aspiration site unless not available and patient requires urgent aspiration of fluid

For a larger effusion a therapeutic procedure can be performed where a larger amount of fluid can be aspirated (no more than 1000-1500mls to avoid re-expansion pulmonary oedema).

This should ideally be done in a pleural procedure room. This is done in the same way as a diagnostic tap (step 1-5) but using a pleurocentesis kit. These contain a needle mounted 6FG catheter, 50ml syringe, 3 way tap and sterile collection bag.

  1. Using ultrasound mark the appropriate side and site.
  2. After cleaning with cleaning fluid and using local anaesthetic, the 6Fg catheter can be advanced until fluid is aspirated and then the needle is held steady as the catheter is advanced into the pleural space. The needle is then withdrawn. It is then secured with a small dressing to hold it in place.
  3. The fluid can be drained passively into the bag using the 3 way tap or by actively aspirating 50mls then expelling into collection bag via 3 way tap.

The procedure should be stopped when

  • 1000-1500ml is aspirated or
  • The patient develops discomfort or excessive coughing     
  • Resistance is met

The catheter is removed and small dressing should be applied. A CXR is usually performed post procedure to exclude a pneumothorax/trapped lung and assess amount of fluid remaining.

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Contraindications to pleural procedures

Contraindications — there are no absolute contraindications to thoracentesis. The procedure should be performed if clinical judgment indicates that the information gained from pleural fluid analysis is sufficiently important for diagnosis and/or determination of therapy that it outweighs the risks of the procedure. However increased caution is warranted in the following situations:

Coagulopathy - ideally INR should be ≤ 1.5 and platelets ≥ 100
Normally anticoagulants including DOACs (see Trust guidelines on DOACs and elective procedures) would be withheld prior to pleural intervention and caution with antiplatelets other than aspirin.
Co-operation - the patient is needed to be able to co-operate with the procedure to keep complications to a minimum
Local infection of skin at insertion site.
Very small amount of fluid
Significantly loculated fluid
Where if the complication of a pneumothorax arose there would be significant respiratory compromise for the patient.

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Chest drain insertion

Chest drain insertion for a pleural effusion
Operator or supervisor must be competent in procedure -if not please contact Respiratory Registrar for advice on bleep 6775.
This should only be done out of hours in an emergency
Ultrasound should be used to guide optimum site for pleural effusions
Please check the plan is not for a thoracoscopy or tunnelled drain as this cannot be done if the effusion is drained to dryness

For the procedure you will need
Cleaning fluid
Gloves and gown
10 to 20 ml of 1% lignocaine
Silk suture
Seldinger chest drain kit pack (with drape, needles, syringes, scalpel and dressing)
Connecting tubing
Chest drain bottle
Sterile water to create under water seal

  1. Explain procedure to patient and document written consent in the case notes (and preferably already given them a patient information leaflet about chest drain insertion - see Appendix 1
  2. Ensure they are comfortable leaning over a table or in the lateral decubitus position and have an assistant to help you with the procedure. This should be done in a pleural procedure room if possible (e.g. side room 2 in J10)
  3. Ensure the oxygen and suction are in working order prior to commencing and that the patient has IV access
  4. Use the ultrasound to confirm adequate amount of pleural fluid to proceed safely with the drain. This should be as close to the triangle of safety as possible depending on amount and position of fluid. Mark the correct side and site.
  5. Sterilise the chest wall with cleaning fluid.
  6. Infiltrate the skin and subcutaneous tissues down to the pleural space where you will be able to aspirate fluid. Using a new needle take a sample of the pleural fluid for analysis
  7. Insert the seldinger chest drain as per the instructions contained in the kit.
    Using the needle and syringe locate the pleural space by aspirating fluid and then pass the guide wire down the needle aiming towards the lung base
    Remove the needle
    Make an incision in the skin about the size of the chest drain you are about to insert (10 to 14F usually) 
    Use the dilators to make a tunnel through the subcutaneous tissue 
    Do not insert the dilator all the way but just until the bevel is into the pleural space
    Finally insert the chest drain and remove the guide wire and internal dilator.
    Attach the chest drain to the underwater seal bottle and tubing, fluid should now be draining into the bottle.
    Secure the drain with a stitch (not a purse string) and apply the dressing.
    No more than 1000-1500ml should be drained initially. The drain should be clamped/3 way tap for about an hour before releasing again.
    If the patient becomes breathless when the drain is clamped, the clamp should be removed and a doctor called immediately
  8. 10. Prescribe analgesia for the patient
  9. 11. Repeat CXR

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Care of the chest drain and removal

Care of the chest drain (Pleural effusion)

  1. Post procedure observations, CXR, chest drain chart and analgesia should be prescribed.

Clear documentation of the procedure should appear in the notes.

Drainage of a large pleural effusion should be controlled to prevent re-expansion pulmonary oedema - no more than 1.5 Litre (1 Litre in a smaller adult) should be drained in the first hour. Thereafter no more than 1 Litre an hour and when less than this can stay on free drainage.  Direct observation is recommended for the first 15mins (do not transfer during this time) to avoid excessive drainage of fluid.  After this every 15mins for first hour, hourly for 3 hours then every 4 hours.

In the case of a pneumothorax or bubbling chest drain should never be clamped.

  1. Explain safe handling of the drain to the patient and give patient information sheet
    • The bottle should never be raised above the level of the tube insertion or water may enter the pleural space
    • The patient can mobilise if drain kept below waist level
    • To inform nursing staff immediately if any part of the drain becomes disconnected.
  2. Immediately after insertion the rate that the fluid is draining should be closely observed to prevent excessive rapid losses.
  3. The chest drain bottle should be changed before it becomes full. The bottle must have an underwater seal.
  4. The drain should be observed for swinging (or bubbling which means a pneumothorax may have developed) each shift and documented in the chest drain observation sheet.
  5. A chest drain that is not swinging is not functioning and the doctor should be alerted to this and should check for kinks, displacement from the pleural space or blockages (by flushing the drain with 20mls of saline).
  6. The dressing should be inspected each day and changed if necessary. 

Removal of the Chest Drain

  1. Usually at least 24hrs after the drain has stopped bubbling and CXR shows re-expansion of the lung for pneumothoraces, and for pleural effusions to be discussed with senior medical member of the team.
  2. Sterilise around the drain with cleaning fluid
  3. Smaller seldinger drains usually do not require a suture to the site. If a large bore chest drain was used then infiltrate the wound edges with lignocaine as the wound will need a suture.
  4. Remove drain in one steady movement
  5. Apply simple dressing
  6. Repeat CXR (if drain was for a pneumothorax)
  7. Inform nursing staff so the patient can be monitored for breathlessness

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Pleurodesis of a malignant pleural effusion with talc slurry


This can be performed in malignant pleural effusions to attempt to reduce recurrence if other treatment options are not appropriate such as thorascopic pleurodesis or indwelling drain - this should be discussed with a Respiratory consultant. The usual agent used is talc slurry. This is performed when the CXR shows the effusion has been drained (the amount draining per day is less important). If lung apposition has not been obtained it may be worthwhile attempting the procedure but it may be less successful.

  1. The procedure can be painful so the patient must have premedication usually with an opiate
  2. Clamp/close 3 way tap of the chest drain end closest to the patient
  3. Using a bladder tip/luer lock 50 ml syringe insert into chest drain, release the clamp and instil lignocaine slowly into pleural space (3mg/kg, maximum 250mg
  4. Then in the same manner instil the talc (2 to 5g) in 50mls of normal saline
  5. Flush drain with another 20mls of normal saline
  6. Clamp the drain for 1 to 2 hours..
  7. Ensure the patient is prescribed analgesia

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Medical Thoracoscopy
Paient information leaflet - Appendix 3

This is a procedure where a fibreoptic camera is inserted into the pleura space to take biopsies of the parietal pleural. This is performed if the pleural aspiration has been non diagnostic but the concern of malignancy or significant pleural pathology remains.  This is done under local anaesthetic (and iv morphine and midazolam) in the bronchoscopy/pleural room in David Beevers on a Tuesday morning. The patient will be admitted the night before and will have had

  • Negative MRSA swabs and INR <1.5 and="" will="" have="" omitted="" antiplatelets="" (other="" than="" aspirin)="" and="" anticoagulants="" as="" per="" trust="" guidelines<="" li="">
  • A cannula should be inserted in the arm on the same side of the effusion.

A dedicated consent form is available and will be filled out by the operator.
After draining the fluid and taking biopsies a clinical decision will be made re insertion of temporary drain plus/minus talc poudrage or a tunnelled indwelling pleural drain. The patient will then be admitted to the ward for a few days.


  1. Scrubs, hats and clogs for all staff in room
  2. Position patient - head to cupboard for left effusion – video stack above patient rear (away from patient for now)
  3. Surgical pause – checklist
  4. US to mark effusion - correct side and site
  5. Check sedation syringes & video capture
  6. Put on mask and scrub – second operator inserts venflon
  7. Open instrument tray
  8. Clean with Chlorprep
  9. Dispense additional kit onto sterile field (19 items)
  10. Transfer scope from scrub trolley
  11. Give sedation
  12. Remark entry site with sterile pen
  13. Apply patient drape, secure to drip stands (sticker to head)
  14. Mayo tray drape (sticker down - open over patient drape)
  15. Move video stack towards patient
  16. Instill Xylocaine
  17. Aspirate for culture sample - leave needle in situ
  18. Prepare scopes
    a. Biopsy forceps into 0 degree scope
    b. Camera into condom (leave card on Mayo tray)
    c. Camera onto 50 degree scope
    d. Light source onto scope – clip light source and camera cable to drape
    e. Suction to catheter and suction machine 
    f. Suction clipped to patient drape
    g. Fog-off on both scopes
    h. 50 degree  scope orientated and focussed
    i. Sharp box open on Mayo tray
    j. Green needle into sharp box
  19. Scalpel to entry point and dissect to pleural space
  20. Trocar inserted, fluid aspirated (1L first then look)
  21. 50 degree scope inserted to examine pleura – record movie
  22. Camera onto 0 degree scope - biopsy x 4 onto card disc (ensure forceps tips remain sterile)
  23. Reinspect using 50 degree scope
  24. Talc instillation (large bottle upright) review with 50 degree scope
  25. Remove trocar and insert 24F drain (cut extra holes and direct to apex) - purse-string and anchor suture
  26. Disconnect camera, light source, suction
  27. Remove drape, chlorprep, gauze and Mefix
  28. Consider further morphine
  29. Connect to bucket opposite side from operator.

After thoracoscopy care

Analgesia - paracetamol regularly, codeine, morphine as needed

Regular observations especially BP which may fall after procedure and require iv fluids. Ensure renal function and blood count remains stable.

Repeat CXR next day to assess whether lung inflated and amount of fluid remaining.

If an Argyle drain has been inserted this can be removed when lung inflated and no evidence of air leak and fluid drained. There will be a purse string suture around the drain to be used to close the wound site. The cancer team is happy to be contacted for advice about when to remove the Argyle drain.

If a tunnelled indwelling drain has been inserted this should NOT be removed but can be disconnected from the underwater drainage system, by a member of staff who is trained to do this under aseptic conditions, when the effusion has been drained. Remember to cap off the drain and conceal drain under a dressing.

Please make sure that all patients have a follow up appointment in Bexley clinic 2 weeks following procedure by contacting cancer secretary Katie on ext. 64159.
Those with tunnelled indwelling pleural catheters should be referred to the District nurses for ongoing drainage in the community - please discuss with bronchoscopy team on ext. 66653 for help with this. 

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Tunnelled indwelling pleural catheter

Tunnelled indwelling Pleural catheters (TIPC)
Patient information leaflet appendix 4

A TIPC is a soft tube which is inserted into the pleural space and tunnelled anteriorly under the skin. This is done under local anaesthetic, usually as a day case, in the bronchoscopy room in David Beevers. This is a (semi) permanent drain used to control fluid mainly in the setting of malignant pleural effusions. (This are now used more commonly to control malignant pleural effusions than performing a talc pleurodesis through a chest drain). There is a one way valve which can be connected to vacuum bottles to drain the fluid at home by the District Nurses.
If there is a large volume of fluid to be drained or the patient has developed an air leak, then the TIPC can be attached to an underwater seal using a special connector (PleurX lockable drainage line 50-7245) to be found in the pleural procedures room (side room 2 in J10).

  • The patient should have a negative MRSA swab and INR <1.5 with="" anticoagulants="" and="" antiplatelets="" (other="" than="" aspirin)="" withheld="" if="" clinically="" possible.="" <="" li="">
  • A cannula inserted
  • A dedicated consent form is available and will be filled out by the operator.


  1. Scrubs, hats and clogs for all staff in room
  2. Position patient - head to cupboard for left effusion
  3. Surgical pause - checklist
  4. US to mark effusion
  5. Insert venflon
  6. Put on mask and scrub
  7. Open 2 towels onto trolley
  8. Open Pleurx kit – sterile tape down whilst opening
  9. Extra kit (scalpel, stitch, Chlorprep)
  10. Clean with Chlorprep
  11. Apply patient drape, secure to drip stands (sticker to head)
  12. Instill Xylocaine
  13. Aspirate for culture sample
  14. Insert guidewire
  15. 1cm incision at guidewire (towards exit point) and exit point
  16. Tunnel drain
  17. Dilate entry site (wire at 90 degrees)
  18. Remove guidewire and dilator and insert drain through plastic introducer - Check cuff position before fully burying drain
  19. Attach drainage bottle if planned
  20. Stitch dilated entry site drain x 2 (ensure stitch not through drain)
  21. Tighten entry port with anchor suture, then one loop onto drain
  22. Clean with Chlorprep
  23. Dressing (ensure pleurx end under dressing if leaving attached to underwater seal)

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Management of a known malignant effusion

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Record: 5964
Clinical condition:

unilateral pleural effusion, Pleural diseases

Target patient group: Those with pleural conditions
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

Investigation of a unilateral pleural effusion in adults
Management of a malignant pleural effusion 
British Thoracic Society Pleural Disease Guideline 2010

Document history

LHP version 2.0

Related information

Not supplied

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