Paracentesis: A Step-by-Step Procedure Guide

Author: V. Dimov, M.D., Clinical Assistant Professor of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio

Indications

New onset ascites or ascites of unknown origin
Patient with a known ascites who has fever, abdominal pain, hypotension or encephalopathy
Symptomatic treatment of large ascites

Contraindications

Uncooperative patient
Uncorrected bleeding diathesis
Acute abdomen that requires surgery
Intra-abdominal adhesions
Distended bowel
Abdominal wall cellulitis at the site of puncture
Pregnancy

Procedure Step-by-Step

Explain the procedure to the patient and obtain a written informed consent, if possible. Explain the risks, benefits and alternatives (RBA).

Commercial paracentesis kits are pre-assembled. If you do not have a commercial kit, this is a list of the equipment you need to perform a successful paracentesis:

16 G Angiocath (or a spinal needle) x 1
10 cc syringe x 1
One-liter vacuum bottle x 5
Thoracentesis kit tubing x 2
Sterile gloves x 2
Betadine swab x 3
Sterile drape x 2
4x4 sterile gauze x 4
Band-aid x 1

Four steps of the paracentesis procedure

1. Ultrasound scan before the procedure
2. Patient preparation
3. Procedure
4. Laboratory results

1. Ultrasound scan before the procedure

If is is very helpful to get an ultrasound scan of the ascites before the procedure. The radiologist will mark the spot for paracentesis. Two things are important:

- What is the distance from the skin to the fluid? Usually 1 cm. It gives you an idea how deep you have to go with the needle before getting fluid in the syringe.

- What is distance to the midpoint of the collection? Usually 3 cm. It gives you an idea how deep you can go with the needle in relative safety. Generally, the advice is as soon as you reach the fluid, to advance the needle just a little and then to thread in the plastic catheter, and to take the needle out.


Ultrasound marking and direction of Angiocath needle (click to enlrage)


Ultrasound report of ascites for paracentesis

2. Patient preparation

Explain the RBA (risks, benefits, alternatives) to the patient. Make sure that he understands and agrees. If the patient does not understand the procedure, he or she cannot provide an informed consent and you have to ask a relative who has a durable power of attorney for health care or is next of kin.

Explain what is going on while performing the procedure, this will alleviate both the patient's anxiety and yours.

Ask the the patient to urinate before the procedure or use a Foley to empty the bladder. Position the patient in the bed with the head elevated at 45-60 degrees to allow fluid to accumulate in lower abdomen.

3. Procedure

Preparation for the procedure:

Get all the things ready at the bedside. Briefly explain to the patient what the different parts of kit are used for. Get a trash bin nearby to dispose of the plastic envelopes of needles and tubing.

The patient should lie on his back in a slightly recumbent position toward the site of paracentesis. Percuss the area of dullness to ensure that is correspond well the the ultrasound marking. Insertion site is inferior to umbilicus and at the level of percussed dullness, usually 2-3 fingerbreadths below the umbilicus.

Clean the area with betadine in a circular fashion from the center out. Apply the sterile drapes. You will place the opened parts of the kit on the drape.

Open the 16 G Angiocath and syringe place them on the sterile drapes. Place the 1-L vacuum bottles nearby.

From this point on, you have to wear sterile gloves, so please ensure that you have everything you need in the sterile area. It is time-consuming to have to reach for, let's say additional tubing in the non-sterile area and then to remove the soiled sterile gloves and to put new ones. Make sure that you have everything you need for the procedure in the sterile area.

Try to make sure that the Angiocath fits the tubing. All needles, syringes and tubing should fit.

Procedure technique:

If the marked site is in the RLQ, pull the skin down and go in with the Angiocath, then release the skin (this is called Z-technique which creates a skin track to stop ascitic fluid from leaking out after the procedure). Aspirate as you go in. Once you reach fluid in the needle, advance the needle just a little, then thread in the plastic part while withdrawing the needle. Aspirate again to make sure that the plastic catheter is still inside the fluid collection. If you get fluid in the syringe, everything is fine, unscrew the syringe and connect the tubing to the 1-L vacuum bottle.

If you cannot get fluid after withdrawing the needle, try to reposition the catheter. If still there is no fluid, you can try to pull out and reintroduce the needle (if kept sterile). Do not push hard or deeper than the midpoint of the collection as seen on the ultrasound scan.

If you are unsuccessful in obtaining ascitic fluid, you can ask for an ultrasound-guided paracentesis.

After the procedure, ask the patient to lie in his bed for 4 hours and the nurse to check vital signs q 1 hr for 4 hours to avoid hypotension.

It is generally recommended to give 25 cc of albumin (25% solution) for every 2 liters of ascitic fluid removed. For example, if the patient had a 4-liter paracentesis, he should receive 50 cc of albumin IV (25% solution) over 2 hours. The rationale for giving albumin is to avoid intravascular fluid shift and renal failure after a large-volume paracentesis.

Complications

Persistent leak from the puncture site
Abdominal wall hematoma
Perforation of bowel
Introduction of infection
Hypotension after a large-volume paracentesis
Dilutional hyponatremia
Hepatorenal syndrome
Major blood vessel laceration
Catheter fragment left in the abdominal wall or cavity

Write a procedure note which documents the following:

Patient consent
Indications for the procedure
Relevant labs, e.g INR/PTT, platelet count
Procedure technique, sterile prep, anesthetic, amount of fluid obtained, character of fluid, estimated blood loss
Any complications
Tests ordered

4. Laboratory results

Send the sample to the lab. Usually, you send only one of the 1-L bottles. The rest of the bottles (2-3, if it was a large-volume paracentesis) are disposed of in the biohazard area.

Order the relevant tests and check them yourself or sign out for somebody to check them.

General labs:
Ammonia, CBC, CMP, albumin, amylase, lipase, INR/PTT.

Labs for paracentesis ascitic fluid:
Protein, albumin, specific gravity, glucose, bilirubin, amylase, lipase, triglyceride, LDH
Cell count and differential
C&S, Gram stain, AFB, fungal
Cytology
pH

Your responsibility does not end with performing the procedure. You have to make sure that somebody follows on the test results and acts accordingly, e.g. prescribes antibiotics if the fluid shows SBP.


Paracentesis fluid analysis of a patient with ascites due to cirrhosis


CMP of a patient with ascites due to cirrhosis

References

Paracentesis. eMedicine.
Paracentesis. NEJM (subscription required)
Paracentesis. Blueprints Clinical Procedures, Google Books
Paracentesis. Handbook Of Gastroenterologic Procedures, Google Books
Paracentesis. Med.buffalo.edu
Practical Procedures - a complete guide
UCSF Hospitalist Handbook - Procedures
Abdominal Paracentesis. Medicineclinic.org
Medicine, Medical Books, Current Clinical Strategies Publishing
Cirrhotic Ascites - clevelandclinicmeded.com
Minimizing ascites - postgradmed.com
Patient information: Abdominal tap - Medline Plus
Arrow Large Volume Abdominal Paracentesis Kit
Videos by Proficient Procedures, Inc. USA, $ 50 for 6 procedure videos
The 'wrong' fluid. GruntDoc.com.

Related reading

Becoming a Rural Doctor, Part 5: Procedures for the Rural Doctor. Rural Doctoring, 2008.

Disclaimer

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Published: 03/20/2006
Updated: 04/17/2008

2 comments:

  1. The rationale for giving albumin is to avoid intravascular fluid shift and renal failure after a large-volume paracentesis.

    ReplyDelete
    Replies
    1. It will not matter how much albumin they give a patient when they have taken way to much fluid as in 20 liters from one man who was in desparate need of a liver transplant. It caused a massive fluid shift and he begin to bleed which they could not stop which lead to exsanguination thus cardiac arrest.

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