Gastroenterology On the Wards Procedures Resident Teaching

Abdominal Paracentesis

Dr Rajit Gilhotra, Gastroenterology AT

Performed to remove fluid in abdominal cavity which can accumulate for various reasons:

  • Liver Cirrhosis with Portal Hypertension
  • Portal vein thrombosis
  • Budd-Chiari
  • Right heart failure
  • Malignancy
IndicationsRelative Contraindications
– Relief of symptomatic ascites (most common)
– Evaluation of new onset ascites
– Acutely decompensated chronic liver disease (diagnostic tap to exclude SBP)
– Acutely decompensated chronic liver disease
– DIC
– Massive ileus with gross bowel distension (can be confused with ascites)

Prior to Procedure

Check BloodsHb, INR, Plt, eGFR.  Discuss with senior if INR >2.5 and platelets <50
Informed consentSigned consent form, discussing the risks of the procedure.  If patient is encephalopathic, may need to contact NOK/EPOA/adult guardian.
Patient PrepGet the patient to empty their bladder.
Lay them completely flat to allow fluid to settle.
Order enough albuminReplacing volume with albumin is to prevent acute renal impairment.  100mls of 20% albumin for every 2L drained;  your aiming to drain 10L of fluid maximum – so you’ll need to order 20% albumin x5 from pathology.  Start the albumin as your are prepping for the procedure, this way you’ll be albe to keep up with the replacement.
FFP +/- platelet replacementGive FFP if INR >3 and platelets, if platelets <30.
Gather the gear The most time consuming part!
Click here for a picture of the equipment you will need
Ultrasound machine if available with sterile probe cover

Locate the Spot

Left or right lower quadrant (left preferred), lateral to the rectus sheath to avoid the inferior epigastric artery.  Ideally with bedside ultrasound:

  • Use widest probe with plenty of gel!
  • Confirm ascites and find the location of the deepest pocket of fluid
  • At least 4cm deep, ideally 6cm or more
  • Percuss to confirm

If you don’t have USS – percuss for dullness, palpate and ensure liver and spleen are out of the way and go for it!  Once you’ve found the spot mark it or use skin freckles/moles/previous paracentesis scars as a guide.

The Procedure

  • Sterile procedure – so clean skin, apply sterile drape
  • Apply local anaesthetic, using at least 5mls – the key to a success is applying enough so the patient is comfortable!
  • Use blade to make small puncture in skin
  • Load the plastic pigtail catheter on to the introducing needle
  • Attach a 20ml syringe to the end of the introducing needle
  • Use Z-Track to advance catheter through the epidermis
  • Intermittently pull back on the syringe
  • The point at which you feel a sudden loss of resistance is the point when the needle has pierced the peritoneum.
  • At this point; pull back on syringe to confirm – you should see ascitic fluid in the syringe
  • Guide plastic catheter over needle into cavity then remove the needle
  • Sandwich the drain in between two tegaderm bandages to secure it in place

Once the drain is in

  • Remove the first 20mls of fluid, fill a purple top (EDTA) and put the rest into a sterile urine jar and blood culture bottles.
  • Request MCS which will include cell count and differential
    • Must be checked EACH and EVERY time you remove ascitic fluid
  • For first ascites drain – request SAAG (see below)
  • Chart 20% albumin on fluid chart
  • Document procedure in the patient’s notes with clear instructions for nursing staff:
    • Remove catheter after 10L drained, or at 6 hours, whichever comes first.
    • Hourly observations while drain is in, then 2 hourly for 6 hours post removal.
    • No need to clamp the drain every 2 Litres while you wait for albumin replacement to happen – if you commenced the albumin as your preparing for the procedure this won’t be an issue anyway.
  • When you have finished draining the fluid, remove the catheter and apply a dressing.

Evaluating new ascites

To calculate the Serum to Ascites Albumin Gradient:

SAAG = Serum albumin – Ascitic fluid albumin

Ascitic fluid albumin level is NOT routinely checked by the lab – need to specifically request it.

SAAG > 11SAAG < 11
Transudative’
high pressure system, ascetic fluid is albumin-poor
‘Exudative
ascetic fluid has high albumin levels
Portal hypertension
Portal venous/Hepatic Venous thrombosis
Right Ventricular failure
Malignancy*
Intro-abdominal infection
Pancreatisis

*If suspecting malignancy as a cause for ascites, send off the entire volume of fluid drained for cytology – highest yield for diagnosis.

Spontaneous Bacterial Peritonitis (SBP)

  • Spontaneous bacterial translocation from bowels into ascitic fluid
  • Commonly Gram-negative bacilli – Klebsiella and E coli
  • Defined as > 250 x10^6/L polymorphs/neutrophils in ascitic fluid
  • If meets criteria – give IV ceftriaxone 2g daily for 5 days

Tips

  • Remember when infiltrating the anaesthetic to draw back being mindful that this group of patients have prominent abdominal wall veins.
  • When choosing a spot:
    • AVOID scars, bruised areas, infected or broken skin
    • AVOID putting the needle through prominent superficial veins.
  • Be confident, have everything prepared, be comfortable, elevate the bed to your height.
  • Use the ultrasound, taking your time to choose an appropriate spot, and look at both lower quadrants.
  • The paracentesis introducing needle has a marking for each centimetre, keep a mental note as you advance it.
  • You will hear two “pops”; one when you enter the subcutaneous layer, and another when you break though the peritoneal layer.
  • Keep the index finger of your non-dominant hand on the skin to act as an anchor and prevent you going in to far, using the middle finger and thumb of your dominant hand to advance the needle.
  • As soon as you hear your second “click”, push forward another centimetre and aspirate your 20mL, keep the needle in position, don’t withdraw or push further, and slide the cannula overtop – this should be smooth, if feeling resistance, your needle likely wasn’t far enough and the cannula is coiled in a subcutaneous tissue layer.  

Special contribution of ‘Tips’ by Dr Annabel White, Gastro Intern CHHHS

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