| Patient Education |
|
Click here for patient education.
|
|
AUTHOR AND EDITOR INFORMATION
Section 1 of 14  
Author: Gil Z Shlamovitz, MD, Assistant Professor of Emergency Medicine, University of Connecticut School of Medicine; Attending Physician, Emergency Department, Windham Memorial Community Hospital, Willimantic, CT; Attending Physician, Emergency Department, Hartford Hospital, Hartford, CT
Gil Z Shlamovitz is a member of the following medical societies: American Academy of Emergency Medicine and American College of Emergency Physicians
Coauthor(s):
Nirav R Shah, MD, MPH, Assistant Professor, Division of General Internal Medicine, New York University, School of Medicine; Associate Investigator, Center for Health Research and Rural Advocacy, Geisinger Health; Senior Analyst, LifeTech Research, Inc
Editors: Andrew K Chang, MD, Assistant Professor, Department of Emergency Medicine, Albert Einstein College of Medicine, Montefiore Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Luis M Lovato, MD, Assistant Clinical Professor, David Geffen School of Medicine at UCLA; Director of Critical Care, Department of Emergency Medicine, Olive View/UCLA Medical Center; Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital; Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Author and Editor Disclosure
Synonyms and related keywords:
paracentesis, abdominal tap, ascites tap, peritoneal tap, abdominal fluid, abdominal fluid drainage, SAAG, serum-ascites albumin gradient, peritonitis, liver disease, cancer, ascites, tense ascites, peritoneal cavity, transudative ascites, exudative ascites, spontaneous bacterial peritonitis, SBP, intra-abdominal fluid
Paracentesis is a procedure in which a needle or catheter is inserted into the peritoneal cavity to obtain ascitic fluid for diagnostic or therapeutic purposes.
Characterization of ascites
Ascitic fluid may be evaluated to help determine its etiology as well as to evaluate for infection or presence of cancer. With regard to differentiation of transudate from exudates, the preferred means for characterizing ascites is the serum-ascitic albumin gradient (SAAG). The SAAG is calculated by subtracting the albumin concentration of the ascitic fluid from the albumin concentration of a serum specimen obtained on the same day. The SAAG correlates directly with portal pressure. Transudative ascites occurs when a patient's SAAG level is greater than or equal to 1.1 g/dL (portal hypertension). Exudative ascites occurs when patients have SAAG levels less than 1.1 g/dL.
Causes of ascites
- Causes of transudative ascites
- Causes of exudative ascites
Spontaneous bacterial peritonitis
Infection of the ascitic fluid without intra-abdominal infection usually occurs in patients with chronic liver disease due to translocation of enteric bacteria. Common pathogens include Escherichia coli, Klebsiella pneumoniae, enterococcal species, and Streptococcus pneumoniae. Patients with renal failure who use abdominal peritoneal dialysis are also at increased risk, as are children with nephrosis or systemic lupus erythematosus. Anaerobic bacteria are not associated with spontaneous bacterial peritonitis (SBP).
An ascitic fluid polymorphonuclear (PMN) count of more than 250 cells/μL (neutrocytic ascites), with the percentage of PMNs in the fluid usually greater than 50%, is presumptive evidence of SBP. Patients whose levels meet these criteria should be treated empirically, regardless of symptoms. Secondary bacterial peritonitis is defined as infected ascitic fluid associated with an intra-abdominal infection.
Diagnostic tap
- New onset ascites: Evaluate fluid to help determine etiology, to differentiate transudate versus exudate, to detect the presence of cancerous cells, or to address other considerations.
- Suspected spontaneous or secondary bacterial peritonitis
Therapeutic tap - Respiratory distress secondary to ascites
- Abdominal pain or pressure secondary to ascites
Absolute - Acute abdomen that requires surgery
Relative - Severe thrombocytopenia (platelet count <20 X 103/μL), coagulopathy (international normalized ratio [INR] >2.0), or both
- Patients with an INR greater than 2.0 should receive fresh frozen plasma (FFP) prior to the procedure. One strategy is to infuse one unit of fresh frozen plasma before the procedure and then perform the procedure while the second unit is infusing.
- Patients with platelet counts less than 20 X 103/μL should receive an infusion of platelets prior to performing the procedure.
- In patients without clinical evidence of active bleeding, routine labs such as prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet counts may not be needed prior to the procedure.1 In these patients, pretreatment with FFP, platelets, or both before the paracentesis is also probably not needed.
- Pregnancy
- Distended urinary bladder
- Abdominal wall cellulitis
- Distended bowel
- Intra-abdominal adhesions
Local anesthesia is used. For more information, see Local Anesthetic Agents, Infiltrative Administration. See Technique for details.
Disposable paracentesis/thoracentesis kits
- Antiseptic swab sticks
- Fenestrated drape
- Lidocaine 1%, 5-mL ampule
- Syringe, 10 mL
- Injection needles, 22 gauge (ga), 2
- Injection needle, 25 ga
- Scalpel, No. 11 blade
- Eight-French catheter over 18 ga x 7 1/2" needle with 3-way stopcock, self-sealing valve, and a 5-mL Luer-Lock syringe
- Syringe, 60 mL
- Introducer needle, 20 ga
- Tubing set with roller clamp
- Drainage bag or vacuum container
- Specimen vials or collection bottles, 3
- Gauze, 4 x 4 inch
- Adhesive dressing
Paracentesis/thoracentesis tray.
- The two recommended areas of abdominal wall entry for paracentesis are as follows (see photo):
- Two centimeters below the umbilicus in the midline (through the linea alba)
- Five centimeters superior and medial to the anterior superior iliac spines on either side
Paracentesis sites. - The authors recommend the routine use of ultrasonography to verify the presence of a fluid pocket under the selected entry site in order to increase the rate of success.2 The ultrasound also helps the physician avoid a distended urinary bladder or small bowel adhesions below the selected entry point. To minimize complications, avoid areas of prominent veins (caput medusa), infected skin, or scar tissue.
Ultrasound ascites. - Patients with severe ascites can be positioned supine. Patients with mild ascites may need to be positioned in the lateral decubitus position, with the skin entry site near the gurney. The lateral decubitus position is advantageous because air-filled loops of bowel tend to float in a distended abdominal cavity.
- Explain the procedure, benefits, risks, complications, and alternative options to the patient or the patient's representative and obtain signed informed consent.
- Empty the patient's bladder, either voluntarily or with a Foley catheter.
- Position the patient and prepare the skin around the entry site with an antiseptic solution.
Application of antiseptic solution. - Apply a sterile fenestrated drape to create a sterile field.
Draping. - Use the 5-mL syringe and the 25-ga needle to raise a small lidocaine skin wheal around the skin entry site. Switch to the longer 20-ga needle and administer 4-5 mL of lidocaine along the catheter insertion tract. Make sure to anesthetize all the way down to the peritoneum. The authors recommend alternating injection and intermittent aspiration down the tract until ascitic fluid is noticed in the syringe. Note the depth at which the peritoneum is entered. In obese patients, reaching the peritoneum may involve passing through a significant amount of adipose tissue.
Local anesthesia - skin wheal.
Local anesthesia - deeper injection. - Use the No. 11 scalpel blade to make a small nick in the skin to allow an easier catheter passage.
Skin nick. - Insert the needle directly perpendicular to the selected skin entry point. Slow insertion in increments of 5 mm is preferred to minimize the risk of inadvertent vascular entry or puncture of the small bowel.
Insertion of needle into selected skin entry point. - Continuously apply negative pressure to the syringe as the needle is advanced. Upon entry to the peritoneal cavity, loss of resistance is felt and ascitic fluid can be seen filling the syringe. At this point, advance the device 2-5 mm into the peritoneal cavity to prevent misplacement during catheter advancement. In general, avoid advancing the needle deeper than the safety mark that is present on most commercially available catheters or deeper than 1 cm beyond the depth at which ascitic fluid was noticed in the lidocaine syringe.
Filling of syringe with ascitic fluid upon peritoneal entry. - Use one hand to firmly hold the needle and syringe in place to prevent the needle from entering further into the peritoneal cavity.
Stabilization of needle and syringe. - Use the other hand to hold the stopcock and catheter and advance the catheter over the needle and into the peritoneal cavity all the way to the skin. If any resistance is noticed, the catheter was probably misplaced into the subcutaneous tissue. If this is the case, withdraw the device completely and reattempt insertion. When withdrawing the device, always remove the needle and catheter together as a unit in order to prevent the bevel from cutting the catheter.
Advancing the catheter over the needle.
Advance catheter over the needle. - While holding the stopcock, pull the needle out. The self-sealing valve prevents fluid leak.
- Attach the 60-mL syringe to the 3-way stopcock and aspirate to obtain ascitic fluid and distribute it to the specimen vials. Use the 3-way valve, as needed, to control fluid flow and prevent leakage when no syringe or tubing is attached.
Sample collection.
Sample collection.
Peritoneal fluid in vials. - Connect one end of the fluid collection tubing to the stopcock and the other end to a vacuum bottle or a drainage bag.
Collecting tube.
Vacuum bottle. - The catheter can become occluded by a loop of bowel or omentum. If the flow stops, kink the tubing to break the vacuum and try to slightly change the patient's position. Then undo the kink in the tubing to see if the flow resumes.
- Remove the catheter after the desired amount of ascitic fluid has been drained. Apply firm pressure, as necessary, to stop bleeding, if present. Place a bandage over the skin puncture site.
Catheter removal.
- After proper antiseptic preparation and local anesthesia, a diagnostic tap can be performed with a 10- to 20-mL syringe and an 18-ga needle.
- After proper antiseptic preparation and local anesthesia, a therapeutic tap can be performed with an IV catheter over the needle connected to drainage tubing.
- In patients who are afebrile, alert, and have no other signs of bacterial peritonitis, ascitic fluid labs are often not necessary to rule out spontaneous bacterial peritonitis (SBP).3
- To minimize the risk of persistent leak from the puncture site, use a small gauge needle or take a "Z" track during insertion of the needle. (During removal of the needle, the subcutaneous tissue will seal on itself.)
- Failed attempt to collect peritoneal fluid
- Persistent leak from the puncture site
- In cases with a persistent leak, a single skin suture might solve the problem.
- The application of an ostomy bag around the puncture site keeps the leak contained until it is eventually sealed off.
- Wound infection
- Abdominal wall hematoma
- Spontaneous hemoperitoneum: This rare complication is due to mesenteric variceal bleeding after removal of a large amount of ascitic fluid (>4 L).
- Hollow viscous perforation (small or large bowel, stomach, bladder)
- Catheter laceration and loss in abdominal cavity
- Laceration of major blood vessel (aorta, mesenteric artery, iliac artery)
- Postparacentesis hypotension
- This delayed complication may occur more than 12 hours after a procedure in which large volumes are taken off.
- Patients can be pretreated with a colloid solution, such as albumin, to decrease the frequency of this complication, though no difference in survival has been noted relative to other plasma expanders.
- Dilutional hyponatremia
- Hepatorenal syndrome
Depending on the clinical situation, fluid may be sent for the following laboratory tests:
- Gram stain
- Cell count (elevated counts may suggest infection)
- Bacterial culture
- Total protein level
- Triglyceride levels (elevated in chylous ascites)
- Bilirubin level (may be elevated in bowel perforation)
- Glucose level
- Albumin level, used in conjunction with serum albumin levels obtained the same day (used to calculate serum-ascitic albumin gradient [SAAG])
- Amylase level (elevation suggests pancreatic source)
- LDH level
- Cytology
Annals of Internal Medicine: The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites.
MedlinePlus: Abdominal tap
National Guideline Clearinghouse: Management of adult patients with ascites due to cirrhosis
New England Journal of Medicine: Management of Cirrhosis and Ascites
University of California, San Francisco, Dept of Medicine: Serum-Ascites Albumin Gradient
| Media file 9:
Insertion of needle into selected skin entry point. |
|  View Full Size Image | |
Media type: Photo
|
| Media file 10:
Filling of syringe with ascitic fluid upon peritoneal entry. |
| View Full Size Image | |
Media type: Photo
|
- McVay PA, Toy PT. Lack of increased bleeding after paracentesis and thoracentesis in patients with mild coagulation abnormalities. Transfusion. Feb 1991;31(2):164-71. [Medline].
- Nazeer SR, Dewbre H, Miller AH. Ultrasound-assisted paracentesis performed by emergency physicians vs the traditional technique: a prospective, randomized study. Am J Emerg Med. May 2005;23(3):363-7. [Medline].
- Reichman E, Simon RR. Emergency Medicine Procedures. ed. New York, NY: McGraw-Hill Professional; 2003.
- Roberts JR, Hedges JR. Clinical Procedures in Emergency Medicine. 4th ed. Philadelphia, PA: WB Saunders Company; 2003.
- Romney R, Mathurin P, Ganne-Carrié N, et al. Usefulness of routine analysis of ascitic fluid at the time of therapeutic paracentesis in asymptomatic outpatients. Results of a multicenter prospective study. Gastroenterol Clin Biol. Mar 2005;29(3):275-9. [Medline].
Paracentesis excerpt Article Last Updated: Dec 12, 2007
Topic originally published: Mar 10, 2006
|
