# Paracentesis and Peritoneal Drain Placement

## Introduction

**Paracentesis** is the percutaneous removal of ascitic fluid from the peritoneal cavity for diagnostic or therapeutic purposes. When large-volume or recurrent ascites requires ongoing management, **indwelling peritoneal drainage catheters** provide a practical solution. These procedures are among the most frequently performed by interventional radiologists, particularly in patients with cirrhosis, malignancy, and heart failure.

## Indications

### Diagnostic Paracentesis

New-onset ascites of unknown etiology. Evaluation for **spontaneous bacterial peritonitis (SBP)** in cirrhotic patients with fever, abdominal pain, or altered mental status. Assessment of ascitic fluid composition to determine etiology.

### Therapeutic Paracentesis

**Tense ascites** causing respiratory compromise, abdominal discomfort, or early satiety. Refractory ascites unresponsive to diuretic therapy. Prior to other IR procedures (e.g., gastrostomy placement) to improve access.

### Indwelling Peritoneal Drain

**Malignant ascites** requiring repeated large-volume paracentesis. **Refractory cirrhotic ascites** in patients who are not candidates for TIPS or transplant. Palliative management to improve quality of life and reduce hospital visits.

## Contraindications

**Severe coagulopathy**: generally considered safe even with elevated INR in cirrhotic patients; routine correction is not recommended by current guidelines. **Disseminated intravascular coagulation** (DIC): relative contraindication. **Extensive adhesions** or loculated fluid (use image guidance to find safe pockets). **Surgical abdomen** requiring operative intervention.

## Preprocedural Assessment

Physical examination to confirm the presence and distribution of ascites. **Ultrasound** to identify the largest accessible pocket, mark the puncture site, and avoid bowel and inferior epigastric vessels. Laboratory evaluation is generally not required before paracentesis in cirrhotic patients per AASLD guidelines. Empty the bladder prior to the procedure to avoid inadvertent puncture.

![Ultrasound image showing a large pocket of ascites with planned paracentesis needle trajectory avoiding bowel loops](paracentesis-us-planning.png)

## Paracentesis Technique

### Patient Positioning

**Supine** with slight lateral tilt toward the puncture side, or **lateral decubitus** to pool fluid. Common puncture sites: **left lower quadrant** (preferred), right lower quadrant, or midline infraumbilical. Avoid visible veins, surgical scars, and the inferior epigastric artery (located approximately 5 cm lateral to midline).

### Procedure Steps

Sterile preparation and draping of the puncture site. Local anesthesia with **1% lidocaine** from skin to peritoneum using a 25-gauge needle followed by a 22-gauge needle. Insert an **18-gauge needle** or paracentesis catheter (e.g., Caldwell needle, Safe-T-Centesis kit) using a Z-track technique to prevent post-procedure leak. Aspirate fluid; send diagnostic samples before connecting to drainage. For large-volume paracentesis (LVP), connect to vacuum bottles or gravity drainage.

### Diagnostic Fluid Analysis

| Test | Significance |
|------|-------------|
| PMN count >250/mm3 | Spontaneous bacterial peritonitis (SBP) |
| SAAG ≥1.1 g/dL | Portal hypertension (cirrhosis, CHF, Budd-Chiari) |
| SAAG <1.1 g/dL | Non-portal hypertensive (malignancy, TB, pancreatitis) |
| Total protein | Subclassifies within SAAG categories |
| Culture (blood culture bottles) | Identifies causative organism |
| Cytology | Malignant ascites detection |
| Glucose, LDH, amylase | Secondary peritonitis, pancreatitis |

**Cell count and differential**: PMN count greater than 250 cells/mm3 suggests SBP. **Albumin**: calculate **serum-ascites albumin gradient (SAAG)**. SAAG 1.1 g/dL or greater: portal hypertension (cirrhosis, heart failure, Budd-Chiari). SAAG less than 1.1 g/dL: non-portal hypertensive (malignancy, tuberculosis, pancreatitis). **Total protein**: helps subclassify within SAAG categories. **Culture**: inoculate blood culture bottles at the bedside for highest sensitivity. **Cytology**: if malignant ascites is suspected. **Glucose, LDH, amylase**: additional markers when indicated.

## Large-Volume Paracentesis

### Volume and Rate

Typically drain **4-6 liters** or more in a single session. Can safely drain the entire volume in one sitting with appropriate albumin replacement. Duration: 1-3 hours depending on flow rate and volume.

### Albumin Replacement

For LVP of **greater than 5 liters**, administer **6-8 g of albumin per liter removed** to prevent **post-paracentesis circulatory dysfunction (PPCD)**. PPCD manifests as renal impairment, hyponatremia, and increased mortality. Albumin replacement is not necessary for therapeutic paracentesis of less than 5 liters in most patients.

![Large-volume paracentesis setup showing vacuum bottles connected to the drainage catheter](lvp-setup.png)

## Indwelling Peritoneal Drain Placement

### Tunneled Catheter (PleurX/PeritX Type)

**Tunneled catheter** with a polyester cuff positioned in a subcutaneous tunnel to reduce infection risk. Placed under ultrasound and fluoroscopic guidance using the Seldinger technique. Catheter tip positioned in the largest fluid pocket; cuff tunneled 3-5 cm from the skin exit site. Patients or caregivers trained to drain at home every 1-3 days as needed. Typical drainage volume: 1-2 liters per session.

### Complications of Indwelling Drains

**Infection/peritonitis**: 3-5%; reduced by cuff-mediated tunnel; requires antibiotics and possible catheter removal. **Catheter occlusion**: fibrin sheath or omental wrapping; managed with tPA instillation or catheter exchange. **Protein and electrolyte depletion**: monitor nutritional status with frequent drainage. **Leakage** around the catheter site; improved with proper tunnel length and cuff positioning. **Catheter migration or dislodgement**.

## Complications of Paracentesis

**Persistent leak** from the puncture site: occurs in 5% of cases; Z-track technique reduces risk; manage with pressure dressing or skin suture. **Hemorrhage**: rare (less than 1%); avoid inferior epigastric vessels with US guidance. **Bowel perforation**: extremely rare with US guidance. **Infection**: rare with proper sterile technique. **Hypotension**: from PPCD; prevented with albumin replacement.

![Tunneled peritoneal drain catheter with subcutaneous cuff positioned for home drainage of malignant ascites](peritoneal-drain-catheter.png)

## Key Clinical Pearls

Ultrasound guidance should be used for all paracentesis procedures; it reduces complication rates and improves success, particularly in patients with small-volume or loculated ascites. The Z-track technique (angling the needle so the skin and peritoneal puncture sites are offset) significantly reduces post-procedure ascites leakage. In cirrhotic patients, routine correction of coagulopathy before paracentesis is not recommended; cirrhotic coagulopathy represents a rebalanced hemostatic state. For patients requiring paracentesis more frequently than every 2 weeks, consider TIPS, tunneled peritoneal drain, or peritoneovenous shunt as alternatives.

## References

1. Runyon BA. 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.
2. Defined Defined Defined Defined Bernardi M, Caraceni P, Navickis RJ, Wilkes MM. Albumin Infusion in Patients Undergoing Large-Volume Paracentesis. Hepatology. 2012;55(4):1172-1181.
3. Defined Defined Defined Defined Defined Defined Defined Rosenberg S, Courtney A, Englesbe M, et al. Comparison of Percutaneous Management Techniques for Recurrent Malignant Ascites. J Vasc Interv Radiol. 2004;15(10):1129-1131.
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