Paracentesis is the removal of fluid from the peritoneal cavity through the use of a needle for either therapy (to relieve patient symptoms) or diagnosis (to determine causes or complications of ascites). The procedure is generally well-tolerated and simple to perform, especially with the general availability of bedside ultrasound.
DIAGNOSTIC
To analyze abnormal fluid collection in peritoneal space to determine etiology or pathologic conditions (e.g., infection). Most commonly for diagnosis of spontaneous bacterial peritonitis (SBP).
THERAPEUTIC
To evacuate ascites for symptomatic relief, usually of shortness of breath and discomfort from abdominal distention. Paracentesis decreased in-hospital mortality 24% when done early (within 24 h of admission) as opposed to later in one large study (Orman ES et.al).
CONTRAINDICATIONS
Absolute Contraindications
Disseminated intravascular coagulopathy
Relative Contraindications
Intra-abdominal adhesions
Abdominal wall cellulitis
In second or third trimester pregnancy, an open supraumbilical or ultrasound-assisted approach is preferred
Exercise caution in coagulopathic or renal failure patients.
General Basic Steps
Prepare patient
Anesthesia
Ultrasound
Perform procedure
Send for fluid analysis
LANDMARKS
Preferred approach: 3 cm superior and medial to the anterior superior iliac spine
Stay lateral to the rectus sheath to avoid the inferior epigastric artery. The abdominal wall is also thinner in this location.
Alternative approach: 2 cm below the umbilicus in the midline. Avoid if the patient has a midline surgical scar.
TECHNIQUE
Supplies
Bedside ultrasound machine, if available
Culture bottles and tubes for cell count, Gram stain, and albumin
Have a low threshold to send a cell count with differential, even if the tap is being performed for primarily therapeutic purposes.
Commercial paracentesis kits containing rigid plastic sheath cannula, if available
If a kit is not available, then the following supplies should be obtained:
Iodine or chlorhexidine swabs
Sterile 4 × 4 gauze
Sterile towels or fenestrated drape
Sterile and nonsterile gloves
Sterile 60-cc syringes for collecting fluid sample
10-cc syringe for anesthesia
1% to 2% lidocaine (preferably with epinephrine)
Skin anesthesia needles
25- or 27-gauge 1.5-inch needle (local anesthesia)
20- or 22-gauge 1.5-inch needle (local anesthesia)
18-gauge needle (inoculating specimen tubes)
Paracentesis needles
22-gauge needle for diagnostic taps, 18-gauge needle for therapeutic taps
1.5 inch should be sufficient, may need 3.5 inch (spinal needle) for obese patients
Adhesive bandage
Patient Preparation
Direct the patient to urinate or empty the bladder via urinary catheterization
Ultrasonography (preferred, but not essential). Bedside ultrasonography is used to verify that the chosen site has a large fluid pocket with no bowel adhesions.
Sterilize the area where the needle will be inserted with copious povidone–iodine solution or similar surgical prep
Drape the area with sterile towels or sterile fenestrated drape
Patient Positioning
If there is a large amount of ascites, the patient may be placed in a supine position with the head of the bed slightly elevated
Patients with lesser amounts of ascites may be placed in a lateral decubitus position for optimal pooling of fluid. Left lateral decubitus may be ideal, as this is generally the most fluid-rich area.
Analgesia
Produce local anesthesia using up to 5 mg/kg of 1% lidocaine with epinephrine
Raise a subcutaneous wheal with a small-bore (25- or 27-gauge) needle, and then generously infiltrate the deeper tissues in the area of the paracentesis needle’s eventual passage using a longer, larger-bore needle
Anesthetize to the depth of the peritoneum
Needle Insertion
Standard-sized (1.5-inch) metal needle will be sufficient in most cases
A longer (3.5-inch) spinal needle may be necessary in obese patients
For diagnostic taps, a smaller-gauge (22–20 gauge) needle should be utilized to decrease the chance of postprocedural fluid leak
For therapeutic taps, a larger (18 gauge) needle may be used to hasten fluid evacuation
Attach needle to a 60-mL syringe
Advance the needle in slow, controlled 5-mm increments with continuous gentle aspiration of the syringe. A “Z-tract” method may be employed to decrease the risk of postprocedural fluid leak (FIGURE 28.1).
Overlying skin is pulled by an assistant or by the non–needle bearing hand 2 cm in the caudal direction