Abdominal Paracentesis

16 Abdominal Paracentesis

Wael E.A. Saad

Indications

Symptomatic ascites
- Abdominal distention
- Abdominal discomfort
- Shortness of breath
Question of infection (fever) – spontaneous bacterial peritonitis
Asymptomatic ascites of unknown etiology (diagnostic)
An abdominal paracentesis is a prerequisite for an invasive hepatic procedure, particularly a transcapsular procedure (intentional or inadvertent capsular transgression) to potentially reduce the risk of hepatic capsular bleeding (controversial, not proven to reduce bleeding, but it is a common practice). An abdominal paracentesis is done prior to the following procedures:
- Percutaneous transhepatic procedures
  - Percutaneous liver biopsy (random versus lesion specific)
  - Percutaneous transhepatic cholangiography with or without biliary drain placement
  - Percutaneous transhepatic venography with or without venoplasty
- Procedures that may have hepatic capsule transgression
  - Transjugular intrahepatic portosystemic shunt (TIPS) procedure
  - Transjugular liver biopsy

Contraindications

Relative Contraindication

Uncorrected coagulopathy (relative)
Small amount of fluid for therapeutic procedure (for therapeutic intentions)

Preprocedural Evaluation

Evaluate Prior Cross-Sectional Imaging

Evaluate

The size and extent of ascites
If ascitic fluid is loculated or confined in a certain area. This is where to perform a limited/focused ultrasound preprocedure.
Whether in small to moderate amounts of ascites, fluid has accumulated in the perihepatic region only
If there is focal wall thickening or associated masses to help identify or confirm the suspected diagnosis. Areas of peritoneal masses/implants should be avoided because they may increase the risk of bleeding.
An enhancing peritoneal lining may be due to infection, tumor, or subacute/chronic hemoperitoneum
For the presence of high-density fluid (>30 HU), which may represent infected fluid, bile, or blood -has a high probability of septations and/or loculations

Look for adjacent organs that can be inadvertently traversed

Transgression of organs is not a common problem.

It may be more common with small amounts of ascitic fluid.

Organs that may be transgressed include bowel (especially small bowel, which may float in the ascetic fluid).

Plan a paracentesis that is safe and away from adjacent structures and organs (Fig. 16.1)

Fig. 16.1 Paracentesis performed from adjacent to the liver that has an adhesive band between the right liver lobe and the peritoneum. (A) Axial computed tomography (CT) image with contrast enhancement at the level of the aortic hiatus. There appears to be tenting of the hepatic parenchyma toward the peritoneum at the midaxillary line (arrow). Occasionally the majority, if not all, of the ascites fluid is perihepatic, which requires a right upper quadrant access paracentesis rather than the more common lower quadrant sites. It is important to avoid the liver capsule and/or mistaking a large and distended gallbladder for a loculated fluid collection (A, ascites; L, liver; IVC, inferior vena cava; H, right hepatic vein; Ao, aorta; S, stomach; Sp, spleen). (B) Gray-scale ultrasound image of the upper abdomen (top) and schematic sketch of it (bottom). The band is tenting toward the peritoneum (*). The operator avoided the band. In addition, the operator did not go deep with the needle avoiding transgression of the liver capsule (A, ascites; L, liver). (C) Gray-scale ultrasound image of the upper abdomen (top) and schematic sketch of it (bottom). The 21-gauge access needle (arrow) is seen traversing the peritoneum (arrowheads). The operator avoided the band. In addition, the operator did not go deep with the needle avoiding transgression of the liver capsule (A, ascites; L, liver).

Evaluate Preprocedure Laboratory Values

Laboratory value evaluation mostly revolves around ruling out coagulopathy.
- Suggested coagulopathy thresholds for thoracentesis are
  - International normalized ratio (INR): ≤2.0
  - Platelets (PLT): ≥50,000
  - Activated partial thromboplastin time (aPTT): ≤65 seconds

Obtain Informed Consent

Indications

See Indications above
Technical success in placing a drain in the gallbladder is high (99–100%).

Alternatives

To refuse the procedure

Procedural risks

Major complications occur in <1% of patients.

Common postprocedural complications include

Anterior abdominal wall/inferior epigastric artery hematoma

Hypotension and hyponatremia

Hemoperitoneum

Peritonitis (theoretically)

Bowel perforation

Bleeding

This is the most common complication (minor or major).

Bleeding occurs in 0.2–2.0% (<1.0% if real-time ultrasound guidance is used).

Bleeding can take several forms.

Skin bleeding/hematoma (0–0.5%)

Hemoperitoneum (rare)

Rectus sheath (inferior epigastric hematoma) (0–1.9%)

Inferior epigastric artery pseudoaneurysm (<0.5%)

Bleeding may be transient with or without blood transfusion.

Blood transfusion is required in 0–0.9% of cases.

The source of bleeding is usually

Inferior epigastric artery

Anterior abdominal wall portosystemic portal hypertension collateral

Skin bleed

Equipment

Ultrasound Guidance

Multiarray 3.5–5.0 MHz ultrasound transducer
Transducer guide bracket (usually not necessary)
Sterile transducer cover

Standard Surgical Preparation and Draping

Chlorhexidine skin preparation/cleansing fluid
Fenestrated drape

Local Infiltrative Analgesia Administration

21-gauge infiltration needle
10 to 20 mL 1% lidocaine syringe

Sharp Access Devices

11-blade incision scalpel
18-gauge needle that allows a 0.035-inch or 0.038-inch wire
21-gauge needle that allows a 0.018-inch wire
A 15- to 20-cm-long needle (18- to 21-gauge) may be required to access the peritoneum in obese patients. The majority of patients can have their anterior abdominal wall traversed with a 7- to 8-cm-long needle.