Back to top

Gastroenterology - Paracentesis


New ascites (for evaluation)

Unwell patient with ascites (to exclude spontaneous bacterial peritonitis)

Symptomatic ascites (to reduce abdominal discomfort and cardiorespiratory compromise)


Paracentesis discussed with admitting team (testing, limits of drainage)

Contraindications (absolute in bold)

Disseminated intravascular coagulation (raised INR or thrombocytopenia not a contraindication)

Abdominal wall abnormalities (cellulitis, scars, haematomas, hernias, engorged cutaneous vessels)

Intra-abdominal adhesions (bowel tethered to abdominal wall)

Ileus and bowel distension (unless ultrasound-guided)


Paracentesis by interventional radiology

Informed consent

Medical emergency

Consent is not required if the patient lacks capacity or is unable to consent

Brief verbal discussion is recommended if the situation allows


Written consent (including to receive albumin)

More complex non-emergency procedure with higher risk of complications

Potential complications

Failure (of placement or drainage)


Vascular injury and bleeding (<1%)

Visceral perforation (<0.2%)

Abdominal wall haematoma

Persistent leaking of ascites (5%)

Infection (localised or introduced to ascitic fluid <1%)

Circulatory dysfunction (hypovolaemia, hyponatraemia, hepatorenal syndrome if >5l drained)

Procedural hygiene

Standard precautions

Aseptic non-touch technique

PPE: surgical mask, sterile gloves, sterile surgical gown, sterile ultrasound cover and gel


Any monitored bed space


Procedural clinician and assistant


Ultrasound machine with curvilinear ultrasound probe (abdominal) and sterile probe cover

Surgical marker pen

10ml syringe and 25g and 21g needles (skin and subcutaneous anaesthesia)

21g needle and 30-60ml syringe (for diagnostic paracentesis)

14-16g paracentesis catheter or appropriate alternative


Three-way tap

Luer lock drainage bag

Transparent dressing

Gauze and tape


Supine with head slightly elevated (and empty bladder)

Roll slightly to the left if choosing left lower quadrant (preferred location, see below)

Measure 3cm medial and cephalad to the anterior superior iliac spine

Using ultrasound, mark a pocket of ascitic near this point, and measure abdominal wall thickness

If no pocket of fluid visualised, consider another site (avoiding the rectus sheath)

In recurrent ascites, ask the patient where drainage has previously worked well


20% albumin (used if >5l drained, 100ml for every 3l drained)

10ml lignocaine 1% with adrenaline (1:100,000)

Sequence (anaesthesia with Z-track technique)

Infiltrate 1-2ml of lignocaine tangentially at the entry site, raising a skin wheal, then remove needle

Pull skin at entry site 2cm downwards, and maintain this position during further infiltration (Z-track technique)

Infiltrate 5ml of lignocaine in the same direction as planned for paracentesis

Advance the needle in 5mm increments, aspirating prior to injection with each needle advance

Once ascitic fluid is aspirated, withdraw the needle (noting depth)

Release skin and allow two minutes for anaesthetic to take effect before performing paracentesis

Sequence (diagnostic paracentesis)

Attach 30-60ml syringe to 21g needle (increase sample size to 60ml if testing cytology)

Pull skin at entry site 2cm downwards, and maintain this position during further infiltration (Z-track technique)

Advance the needle into the peritoneal cavity applying constant negative pressure

Obtain flashback of ascitic fluid then advance a few more millimetres and fill syringe

Remove the needle and press firmly over the site with gauze for one minute

Apply an occlusive dressing

Sequence (therapeutic paracentesis)

Using a scalpel, make a small incision at the entry site to enable passage of catheter

Insert the needle stylet through the catheter and attach a 10ml syringe to the end

Pull skin at entry site 2cm downwards, and maintain this position during further infiltration (Z-track technique)

Use the non-dominant hand on the patient’s abdomen to guide the catheter

Advance the catheter into the peritoneal cavity, applying constant negative pressure

Once ascitic fluid enters the syringe, stop advancing and slide the catheter into the peritoneal cavity

Once fluid is aspirated, the non-dominant hand can be used to assist catheter placement

Remove the stylet and place a gloved thumb over the cannula

Attach the three-way tap secure the cannula with tape

Using a 30-60ml syringe, withdraw a sample of ascitic fluid (increase sample size to 60ml if testing cytology)

Attach the Luer lock drainage bag

Apply a transparent dressing around the catheter, tethering it to the skin

Distally tape the catheter to the skin to prevent pulling

Sequence (ongoing drainage)

Maintain cardiac monitoring throughout drainage

Administer 100ml 20% albumin IV over 1 hour for every 3l fluid drained (only if over 5l drained)

Cease drainage when output stops or is less than 100ml/hour for two hours (maximum drainage time six hours)

After removal of catheter, apply occlusive dressing and encourage patient to lie on opposite side for two hours

Post-procedure care

Testing (in discussion with managing inpatient team):

Purple EDTA vacutainer (cell count)

Biochemistry vacutainer (albumin, amylase, bilirubin, glucose, protein, triglycerides, tumour markers)

Blood culture bottles (culture)

Urine specimen container (cytology, microscopy, culture and sensitivities)


Insertion site, use of ultrasound, type of catheter used, number of passes, immediate complications

Hourly fluid output, albumin infusion, fluid testing

Follow-up plan arranged and discussed with accepting team (e.g. gastro, ambulatory care, oncology)

Patient advice:

Arrange follow-up with the patient

Advise to present again if abdominal pain, feeling unwell or redness spreading over the site.


Ultrasound guidance improves success and minimises complication

Rapid paracentesis in spontaneous bacterial peritonitis has a mortality benefit


We recommend paracentesis be performed through the thin abdominal wall in the left lower quadrant, avoiding midline abdominal vessels (the inferior epigastric artery runs from lateral to the pubic tubercle cephalad within the rectus sheath). The right lower quadrant is less desirable due to possible caecal distension with gas.

The Z-tract technique is the most effective way to prevent ongoing leaking of ascites. The skin is displaced 2cm before anaesthesia infiltration and paracentesis to misalign the epidermis and peritoneal puncture sites. This technique requires some practice, with one hand displacing the abdominal skin, while the other hand controls the syringe and plunger.

A solid metal 22g needle (or spinal needle if obese) is recommended for diagnostic paracentesis. A variety of larger catheters (such as suprapubic catheters, peritoneal dialysis catheters, ascitic drains and Seldinger sets) can be used for therapeutic paracentesis to speed removal of fluid. We have described the insertion method for a blunt catheter over an introducer, which may need to be modified to the equipment available in your department. Plastic sheathed cannulas are avoided for paracentesis when using a Z-track technique, as occasionally the plastic sheath may tear into the abdominal wall.

Studies suggest the bleeding risk following paracentesis is low, and patients with liver disease, elevated INRs or thrombocytopenia do not require treatment of coagulopathy before paracentesis. Only those with clinically apparent disseminated intravascular coagulation or hyperfibrinolysis require treatment to decrease their risk of bleeding.

We recommend colloid replacement for large volume paracentesis (when draining >5l in total) to minimise circulatory dysfunction. Meta-analyses suggest a trend towards mortality reduction with albumin use and support current recommendation to give 6-8g of albumin for every litre drained.

Peer review

This guideline has been reviewed and approved by the following expert groups:

Emergency Care Institute

Please direct feedback for this procedure to


NSW Agency for Clinical Innovation. Paracentesis. Sydney: ACI; 2019.

Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.

Dunn RJ, Borland M, O’Brien D (eds.). The emergency medicine manual. Online ed. Tennyson, SA: Venom Publishing; 2019.

Runyon BA. Diagnostic and therapeutic abdominal paracentesis. In: UpToDate. Waltham (MA): UpToDate. 2019 November 6. Available from:

Cline DM, Ma OJ, Cydulka RK, Meckler GD, Thomas SH, Handel D. Tintinalli’s emergency medicine. 2012. 7th ed. New York: McGraw-Hill.

Thomsen TW, Shaffer RW, White B, Setnik GS. Videos in clinical medicine. Paracentesis [published correction appears in N Engl J Med. 2007 Feb 15;356(7):760]. N Engl J Med. 2006;355(19):e21. doi:10.1056/NEJMvcm062234

Aponte EM, O’Rourke MC. Paracentesis. Stat Pearls. 2020 May. Available from:

Bernardi M, Caraceni P, Navickis RJ. Does the evidence support a survival benefit of albumin infusion in patients with cirrhosis undergoing large-volume paracentesis?. Expert Rev Gastroenterol Hepatol. 2017;11(3):191-192. doi:10.1080/17474124.2017.1275961

Millington SJ, Koenig S. Better with ultrasound: paracentesis. Chest. 2018;154(1):177-184. doi:10.1016/j.chest.2018.03.034

© Agency for Clinical Innovation 2021