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Procedure Playbook

Ultrasound-Guided Paracentesis

Diagnostic and therapeutic drainage of peritoneal ascites under real-time ultrasound guidance.

Sedation
Local anesthesia
Bleeding Risk
Low (SIR Cat 1)
Key Risk
Ascites leak · PPCD
Antibiotics
Not routine
Follow-up
Vitals q30min × 1h
1

Indications / Contraindications

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Indications

  • Diagnostic: New-onset ascites of unclear etiology — fluid analysis to determine cause
  • Therapeutic: Symptomatic tense ascites causing dyspnea, abdominal pain, early satiety
  • Concern for spontaneous bacterial peritonitis (SBP) — obtain cell count + culture
  • Drainage of loculated fluid collections not amenable to catheter

Contraindications

  • Absolute: Hemodynamic instability · Uncorrectable coagulopathy · No safe access window
  • Relative: Overlying cellulitis/skin infection · Surgical scars at access site (tethered bowel risk) · Pregnancy (use US guidance, avoid gravid uterus) · Massive organomegaly
  • Note: Mild-moderate coagulopathy and thrombocytopenia common in cirrhotic patients and are generally NOT contraindications — routine lab correction is not required for simple paracentesis
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Pre-Procedure Checklist

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Review imaging. Confirm ascites volume and distribution. Identify largest accessible pocket. Note surgical scars (tethered bowel risk).
Labs (SIR Category 1 — low risk). Routine coagulation labs NOT required for simple paracentesis. Check INR/platelets only if: bleeding diathesis, severe liver dysfunction, or anticoagulated. If checked: INR <2.0, platelets >50K.
Anticoagulation. Hold oral/IV anticoagulation when medically appropriate. Hold antiplatelets (except aspirin/NSAIDs). Heparin: hold 4–6h; LMWH: hold 24h; Warfarin: hold 5d; DOACs: hold 24–48h.
IV access. Required for large-volume paracentesis (>5 L). Plan for albumin replacement: 6–8 g/L of fluid removed in cirrhotic patients to prevent post-paracentesis circulatory dysfunction.
Consent. Discuss: bleeding, infection, bowel perforation, ascites leak, post-paracentesis circulatory dysfunction (hypotension, hyponatremia, renal impairment).
Fluid analysis plan. Decide which tests to send: cell count/diff, albumin (for SAAG), total protein, gram stain/culture, +/- cytology, amylase, triglycerides, bilirubin, LDH.
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Relevant Anatomy

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Access Site

  • Ideal landmark: 3 cm medial and 3 cm superior to the ASIS — lateral to the rectus sheath (linea semilunaris), in the LLQ or RLQ
  • Avoids the inferior epigastric artery (runs deep to rectus abdominis within the rectus sheath)
  • LLQ often preferred — sigmoid colon tends to float; cecum in RLQ may be more fixed
  • Midline infraumbilical approach is an alternative if lateral approach unavailable (avascular linea alba)
  • Always confirm with US — the landmark guides initial probe placement, but final access site is determined by the largest safe fluid pocket

Danger Structures

  • Inferior epigastric artery: Runs within the rectus sheath — always access lateral to rectus to avoid
  • Distended bladder: Ensure patient has voided or has Foley prior to procedure
  • Tethered bowel: Surgical scars may cause bowel adhesion to anterior abdominal wall — US to confirm clear window
  • Organomegaly: Splenomegaly (LLQ) or hepatomegaly (RUQ) — confirm on US before access
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Technique

Default RadCall approach · share your own below

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RadCall Standard Default

Supplies

Ultrasound + sterile probe cover ChloraPrep Sterile drape 1% lidocaine 22G needle (anesthesia) Paracentesis needle/catheter kit (sheathed) 60 mL syringe Vacuum bottles + tubing Specimen tubes Sterile dressing

Steps

1

Position + US survey

Patient supine. Perform US survey to identify largest accessible fluid pocket. Confirm no bowel or vessels in intended path. Mark skin entry site. Measure depth to fluid.
▶ Access site landmark
Paracentesis access site: 3 cm medial and 3 cm superior to ASIS, lateral to rectus sheath
Ideal access: 3 cm medial and 3 cm superior to the ASIS. Lateral to the rectus sheath to avoid the inferior epigastric artery.
▶ US survey — LLQ fluid pocket + Doppler
Color Doppler US of LLQ showing vessel check at planned paracentesis access site B-mode US measuring distance from skin to ascitic fluid pocket in LLQ B-mode US confirming no vessels along needle trajectory in LLQ
2

Prep + drape

Sterile prep with ChloraPrep. Drape access site. Apply sterile cover to US probe.
3

Local anesthesia

Anesthetize skin to peritoneum with 1% lidocaine using 22G needle under US guidance. Do not puncture peritoneum — infiltrate up to it and withdraw.
▶ Z-track technique
Z-track needle insertion technique for paracentesis
Z-track: Pull skin 2 cm caudally before inserting needle. Release skin after withdrawing needle — creates an oblique tract that self-seals, reducing post-procedure ascites leak.
4

Access

Create 3–5 mm skin nick. Advance sheathed paracentesis needle into peritoneal cavity under real-time US guidance. Aspirate to confirm free-flowing fluid.
▶ US-guided needle insertion
Ultrasound-guided needle insertion for paracentesis showing needle tip in anechoic fluid
Real-time US guidance: keep the needle in the plane of the beam. Visualize the bright echogenic needle tip entering the anechoic fluid pocket. Confirm ≥3 cm fluid depth and absence of bowel before advancing.
5

Sample collection

Aspirate 60 mL for diagnostic labs. For cytology, collect ≥200 mL for adequate cellularity. Send: cell count/diff, albumin, total protein, gram stain + culture (inoculate blood culture bottles at bedside).
6

Therapeutic drainage

Remove inner needle, connect sheath to vacuum bottles via valved tubing. Reposition patient as needed. Apply gentle contralateral abdominal pressure to facilitate complete drainage.
▶ Drainage setup
Paracentesis therapeutic drainage setup with vacuum bottles and specimen collection
Connect catheter hub → stopcock → vacuum bottles (1 L each, placed below patient). Use the stopcock side port with a 60 mL syringe for diagnostic specimen collection. Remember albumin replacement (6–8 g/L) if >5 L removed in cirrhotic patients.
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Completion

Remove catheter. Apply dry sterile dressing or Dermabond if leak concern. Document fluid color, volume, and appearance. For >5 L: begin albumin infusion (6–8 g per L removed).
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5

Troubleshooting

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Problem

No fluid return after needle insertion

Likely cause: Needle not deep enough, loculated fluid, or bowel interposition.

Next step: Confirm needle tip position with real-time US. Adjust depth or angle. If loculated, reposition patient or select a different pocket. Consider using a longer needle if abdominal wall is thick.

Problem

Bloody aspirate

Likely cause: Traumatic tap (vessel laceration) vs. pre-existing hemorrhagic ascites (malignancy, anticoagulation).

Next step: If bloody on initial aspiration, send fluid for hematocrit — if ascites Hct is <1% of serum Hct, likely traumatic. If persistent bright red blood, stop procedure and monitor. Hemorrhagic ascites (malignancy) will not clot in the tube; traumatic tap will.

Problem

Persistent ascites leak at puncture site

Likely cause: Most common complication (~5%). Due to persistent communication between peritoneal cavity and skin through needle tract.

Next step: Apply Dermabond or purse-string suture. Position patient on contralateral side to shift fluid away. An ostomy bag can be applied as temporizing measure. Consider Z-track technique for future access.

Problem

Flow stops during drainage

Likely cause: Catheter kinked, omentum or bowel plugging side holes, fluid redistributing.

Next step: Reposition patient (roll toward catheter side). Gently flush with saline. Apply gentle abdominal pressure contralaterally. If still no flow, may need to reposition catheter under US.

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Complications

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Immediate

  • Ascites leak (~5%) — most common; Dermabond, suture, or ostomy bag
  • Bleeding (<1%) — vessel laceration; figure-of-eight suture at entry site; laparotomy rarely needed
  • Bowel perforation (<1%) — usually self-sealing; monitor for peritonitis signs
  • Hypotension — from rapid large-volume removal without albumin replacement

Delayed

  • Post-paracentesis circulatory dysfunction (PPCD) — hypovolemia, hyponatremia, renal impairment after large-volume drainage without albumin; can occur 12–72 hours post
  • Infection — rare with sterile technique; cellulitis at puncture site
  • Persistent leak — may require additional closure or indwelling catheter consideration
7

Post-Procedure Care

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Monitoring

  • Vitals q30 min × 1 hour (especially large-volume paracentesis)
  • Monitor puncture site for bleeding, infection, or fluid leak
  • Document fluid color, clarity, and total volume removed
  • No routine post-procedure imaging required

Albumin Replacement

  • >5 L removed in cirrhotic patient: Administer 25% albumin 6–8 g per liter of fluid removed
  • Begin infusion during or immediately after drainage
  • Prevents PPCD (hypovolemia, hyponatremia, hepatorenal syndrome)
  • Anticoagulation: Resume 24 hours post-procedure (earlier if high thrombotic risk)
8

Critical Pearls

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Z-track technique: Pull the skin 2 cm caudally before inserting the needle, then release after removal. This creates a non-linear tract that reduces post-procedure ascites leak.
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Lateral to rectus: Always access lateral to the rectus sheath (linea semilunaris) to avoid the inferior epigastric artery. If in doubt, use color Doppler to map the vessel.
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Don't chase labs in cirrhotics: Routine coagulation testing and correction is NOT required before paracentesis in cirrhotic patients. The INR does not reliably predict bleeding risk in liver disease — these patients have a rebalanced hemostatic system.
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Blood culture bottles at bedside: Inoculate aerobic and anaerobic blood culture bottles directly with ascitic fluid at the bedside — increases culture yield for SBP detection by 50–70% compared to standard lab tubes.
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SAAG ≥ 1.1 = portal hypertension: Serum-ascites albumin gradient is the single most useful test. SAAG ≥1.1 g/dL has 97% accuracy for identifying portal hypertension as the cause of ascites.
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Albumin matters for large volume: For >5 L drainage in cirrhotic patients, albumin replacement (6–8 g/L removed) significantly reduces PPCD, hyponatremia, and mortality. Do not skip this step.
9

Fluid Analysis Reference

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TestNormal / SignificanceInterpretation
SAAG (serum - ascites albumin)≥1.1 g/dLPortal hypertension (97% accuracy): cirrhosis, heart failure, Budd-Chiari, portal vein thrombosis
<1.1 g/dLNon-portal hypertensive: malignancy, TB peritonitis, pancreatitis, nephrotic syndrome
Cell countPMN ≥250/mm³Spontaneous bacterial peritonitis (SBP) — start empiric antibiotics immediately (cefotaxime)
Total protein≥2.5 g/dLExudate (malignancy, TB, pancreatitis). <2.5 = transudate (cirrhosis, heart failure)
LDHRatio ~0.4 normalApproaches 1.0 with infection, bowel perforation, or malignancy
GlucoseLower than serumSuspect infection or malignancy; undetectable → bowel perforation
AmylaseRatio ~0.4 normalElevated with pancreatic leak or bowel perforation
BilirubinAscites > serumBiliary or bowel perforation
Triglycerides>200 mg/dLChylous ascites (lymphatic disruption, malignancy, cirrhosis)
Cytology—Malignant cells; sensitivity ~60–75% with adequate volume (≥200 mL)
Gram stain / culture—Inoculate blood culture bottles at bedside for best yield

Fluid Appearance

  • Clear/straw-colored: Uncomplicated transudative ascites
  • Turbid/cloudy: Infection (SBP) or high cell count
  • Milky/opalescent: Chylous ascites (elevated triglycerides) or cirrhosis
  • Pink/bloody: Traumatic tap, malignancy, or cirrhosis (check Hct)
  • Brown: Elevated bilirubin — biliary or bowel perforation
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References & Resources

Primary sources · Key data · Related procedures
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Key Guidelines

  • SIR clinical practice guideline for image-guided paracentesis
  • AASLD cirrhosis guidelines

Primary References

  • European Association for the Study of the Liver (EASL). EASL Clinical Practice Guidelines for the management of patients with decompensated cirrhosis. J Hepatol. 2018;69(2):406–460.
  • Pache I, Bilodeau M. Severe haemorrhage following abdominal paracentesis in patients with portal hypertension. Aliment Pharmacol Ther. 2005;21(5):525–529.
  • Runyon BA; AASLD. Introduction to the revised American Association for the Study of Liver Diseases Practice Guideline management of adult patients with ascites due to cirrhosis 2012. Hepatology. 2013;57(4):1651–1653.