Paracentesis

Article Author:
Elisa Aponte
Article Editor:
Maria O'Rourke
Updated:
5/17/2019 11:12:43 PM
PubMed Link:
Paracentesis

Introduction

Paracentesis is a procedure performed to obtain a small sample of or drain ascitic fluid for both diagnostic or therapeutic purposes.[1][2][3]

Anatomy

Paracentesis is done in a lateral decubitus or supine position. The ascites fluid level is percussed, and a needle is inserted either in the midline or lateral lower quadrant (lateral to rectus abdominis muscle, 2 cm to 4 cm superomedial to anterior superior iliac spine).[1][2]

  • This positioning avoids puncture of the inferior epigastric arteries
  • Avoid visible superficial veins and surgical scars

The needle is inserted at a 45-degree angle or with a z-tracking technique to reduce the risk of developing an ascites fluid leak.

Indications

Paracentesis should be performed to:

  • Rule out spontaneous bacterial peritonitis in patients with known ascites presenting with concerning symptoms such as abdominal pain, fever, gastrointestinal bleed, worsening encephalopathy, new or worsening renal or liver failure, hypotension, or other symptoms of infection or sepsis
  • Identify the etiology of new-onset ascites
  • Alleviate abdominal discomfort or respiratory distress in hemodynamically stable patients with tense ascites or ascites that are refractory to diuretics (large volume therapeutic paracentesis)[1][2]

Contraindications

There are few absolute contraindications for paracentesis.[3] Coagulopathy and thrombocytopenia (both very common in cirrhotic patients) are themselves not absolute contraindications as the incidence of bleeding complications from the procedure has been shown to be very low.[4] Paracentesis should be avoided in patients with:

  • DIC (consider first administering platelets or FFP)
  • An acute abdomen

It should be performed with caution in:

  • Pregnant patients
  • Patients with organomegaly, ileus, bowel obstruction or a distended bladder

Avoid passing the needle/catheter through sites of skin infection, surgical scars, visibly engorged abdominal wall vessels or abdominal wall hematomas.

Equipment

Prepackaged paracentesis kits with plastic sheath cannulas attached to a syringe and a stopcock are available. Alternatively, traditional large-bore intravenous (IV) catheters or 18 gauge to 20 gauge standard or spinal needles can be used. These can be attached to a syringe for aspiration and then to IV tubing for fluid drainage. If you do not have a pre-packaged kit, you will need the following:

  • sterile gloves
  • sterile drapes/towels
  • chlorhexidine or betadine
  • 1% lidocaine, a needle to inject anesthetic (25 gauge for the skin and a slightly smaller gauge needle for the soft tissue)
  • a 14 or 16 gauge needle or IV catheter for fluid aspiration (spinal needle for obese patients)
  • a 20 cc or 60 cc syringe to collect a sample of fluid 
  • IV tubing
  • vacuum bottles or plastic canisters (if performing large volume paracentesis)
  • 4x4 gauze or bandage
  • hematology, chemistry and microbiology sample tubes and blood culture bottles [3]

Preparation

The preferred site for the procedure is in either lower quadrant of the abdomen lateral to the rectus sheath. Placing the patient in the lateral decubitus position can aid in identifying fluid pockets in patients with lower fluid volumes. Ask the patient to empty his or her bladder before starting the procedure.

Bedside ultrasound should be used to identify an appropriate location for the procedure. Ultrasound can confirm the presence of fluid (Fig. 1) and identify an area with a sufficient amount of fluid for aspiration, thereby decreasing the incidence of both unsuccessful aspiration and complications. Ultrasound increases the success rate of paracentesis and helps to prevent an unnecessary invasive procedure in some patients.[5]The procedure can be performed either after marking the site of insertion or in real time by advancing the needle under direct ultrasound guidance (Fig. 2).

Technique

Prep and drape the patient in a sterile fashion. Cleanse the skin with an antiseptic solution. Administer local anesthesia to the skin and soft tissue (down to peritoneum) at the planned site of needle or catheter insertion. Insert the traditional needle or IV catheter attached to a syringe or the prepackaged catheter directly perpendicular to the skin or using the z-track method which is thought to decrease the chance of fluid leakage after the procedure. This method entails puncturing the skin then pulling it caudally before advancing the needle through the soft tissue and peritoneum. If using a catheter kit, it may be helpful to make a small nick in the skin using an 11-blade scalpel to be able to advance the catheter through the skin and soft tissue smoothly. Apply negative pressure to the syringe during needle or catheter insertion until a loss of resistance is felt and a steady flow of ascitic fluid is obtained. This is paramount to detect unwanted entry into a vessel or other structure rapidly. Advance the catheter over the needle into the peritoneal cavity. After you collect sufficient fluid in the syringe for fluid analysis, either remove the traditional needle (if performing a diagnostic tap) or connect the collecting tubing to it or the catheter's stopcock to drain larger volumes of fluid into a vacuum container, plastic canister or a drainage bag. After you have drained the desired amount of fluid, remove the catheter and hold pressure to stop any bleeding from the insertion site.[1][3]

Peritoneal Fluid Analysis

Send ascitic fluid for laboratory testing including cell count with differential, Gram stain, and fluid culture. Placing some fluid into bacterial culture bottles can help to increase culture sensitivity.[2] Spontaneous bacterial peritonitis is diagnosed when the absolute neutrophil count (PMN) is 250 cells/mm3 or more.[2][3] This is calculated by multiplying the number of white cells by the percentage of neutrophils reported in the differential. Empiric antibiotics, typically a third generation cephalosporin or a fluoroquinolone, should be started in patients with ascites and a high suspicion for spontaneous bacterial peritonitis regardless of the absolute neutrophil count or in patients with an absolute neutrophil count above the cut-off range. Additional tests that can aid in inpatient management include albumin, total protein, lactate dehydrogenase (LDH), glucose, cytology and tumor markers. Albumin, in particular, can be used to calculate the serum-ascites albumin gradient (SAAG) which can assist in determining the etiology of ascites by classifying it as either exudative or transudative.[2][6]

Complications

Paracentesis is a safe procedure [7], however possible complications include:

  • Persistent leakage of ascitic fluid at the needle insertion site. This can often be addressed with a single skin suture.
  • Abdominal wall hematoma or other bleeding
  • Infection
  • Perforation of surrounding vessels or viscera (extremely rare)
  • Hypotension after large volume fluid removal (more than 5 L to 6 L). Albumin is often administered after removal of more than 5 L of fluid to prevent this complication.[3][8]

Clinical Significance

Development of fluid in the peritoneal space or ascites can occur as a result of many different disease states. Performing a paracentesis will help determine the etiology of a patient's ascites. Draining the peritoneal fluid may help identify infection, causes of liver disease or portal hypertension and also relieve symptoms by removing a large volume of fluid. Using bedside ultrasound to identify an ideal pocket of fluid will increase the likelihood of a successful procedure.

Enhancing Healthcare Team Outcomes

Paracentesis is a relatively simple procedure performed at the bedside. The procedure is often performed by the internist, emergency department physician, radiologist, general surgeon or the intensivist. These patients need close monitoring by the nurses as the procedure can be associated with hypotension, bleeding and leakage of fluid. When done for therapeutic reasons, it can quickly relieve symptoms. However, in many cases recurrence of ascites is common and adversely affects the quality of life. [9][10]



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      Contributed by Maria O'Rourke, MyPhuong Mitarai

References

[1] Videos in clinical medicine. Paracentesis., Thomsen TW,Shaffer RW,White B,Setnik GS,, The New England journal of medicine, 2006 Nov 9     [PubMed PMID: 17093242]
[2] Runyon BA, Management of adult patients with ascites due to cirrhosis: an update. Hepatology (Baltimore, Md.). 2009 Jun;     [PubMed PMID: 19475696]
[3] An evidence-based manual for abdominal paracentesis., McGibbon A,Chen GI,Peltekian KM,van Zanten SV,, Digestive diseases and sciences, 2007 Dec     [PubMed PMID: 17393312]
[4] Lack of increased bleeding after paracentesis and thoracentesis in patients with mild coagulation abnormalities., McVay PA,Toy PT,, Transfusion, 1991 Feb     [PubMed PMID: 1996485]
[5] Ultrasound-assisted paracentesis performed by emergency physicians vs the traditional technique: a prospective, randomized study., Nazeer SR,Dewbre H,Miller AH,, The American journal of emergency medicine, 2005 May     [PubMed PMID: 15915415]
[6] Bacterial infections in cirrhosis: A critical review and practical guidance., Bunchorntavakul C,Chamroonkul N,Chavalitdhamrong D,, World journal of hepatology, 2016 Feb 28     [PubMed PMID: 26962397]
[7] Paracentesis of ascitic fluid. A safe procedure., Runyon BA,, Archives of internal medicine, 1986 Nov     [PubMed PMID: 2946271]
[8] De Gottardi A,Thévenot T,Spahr L,Morard I,Bresson-Hadni S,Torres F,Giostra E,Hadengue A, Risk of complications after abdominal paracentesis in cirrhotic patients: a prospective study. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2009 Aug     [PubMed PMID: 19447197]
[9] Ning S,Yang Y,Wang C,Luo F, Pseudomyxoma peritonei induced by low-grade appendiceal mucinous neoplasm accompanied by rectal cancer: a case report and literature review. BMC surgery. 2019 Apr 25;     [PubMed PMID: 31023277]
[10] Jun Jie NG,Teo KA,Shabbir A,Yeo TT, Widespread Intra-abdominal Carcinomatosis from a Rhabdoid Meningioma after Placement of a Ventriculoperitoneal Shunt: A Case Report and Review of the Literature. Asian journal of neurosurgery. 2018 Jan-Mar;     [PubMed PMID: 29492156]