What Is a Paracentesis?
fotostorm / Getty Images
Medically reviewed by Jane Kim, MD
A paracentesis is a procedure where a needle is inserted into the middle or lower part of the abdomen to drain or collect a sample of fluid from the peritoneal cavity, which is the space between the abdominal wall and the organs inside it. An internist might perform a paracentesis to remove excess fluid that might be causing abdominal pressure. A paracentesis can also help in the diagnosis of bacterial infection, stomach cancer, liver cirrhosis, or other conditions that cause fluid buildup.
Purpose
A paracentesis might be performed when fluid builds up in the peritoneal cavity. This abnormal buildup of fluid in the abdomen is known as ascites. A healthcare provider may use paracentesis for therapeutic or diagnostic purposes.
Paracentesis might be used for therapeutic, or treatment, purposes when you have excess fluid in the abdomen. Draining the fluid can quickly relieve pressure on your organs, improving any symptoms the pressure might have been causing.
Paracentesis might be used for diagnostic purposes if you have fluid buildup and healthcare providers want to figure out what's causing it. They might also perform paracentesis for diagnostic purposes if they know you have fluid buildup in your abdomen and think you might have an infection of the abdominal tissues called bacterial peritonitis. Symptoms of bacterial peritonitis include abdominal pain, fever, and low blood pressure.
When used for diagnostic purposes, healthcare providers send samples of the abdominal fluid collected during the procedure to a laboratory for testing. The testing can help rule out bacterial peritonitis. The testing can also help determine what's causing your ascites in the first place, which may include the following conditions:
Liver cirrhosis, the most common cause of ascites
Peritoneal cancer
Nephrotic syndrome, a group of symptoms that suggest your kidneys aren't working properly
Types of Paracentesis
There are two types of paracentesis procedures. Although both involve using a needle or catheter (a flexibile tube that drains fluid) and syringe to collect fluids from the abdomen, there are some key differences between them.
Direct Ultrasound Guidance
Direct ultrasound guidance relies on real-time imaging of the inside of the abdomen to guide the needle or catheter that’s inside into the abdomen. This type of imaging is able to identify the deepest pockets of ascites fluid and prevent organs from being pierced. Using a specialized device laid over the abdomen, low- or high-frequency sound waves create a real-time image.
Indirect Ultrasound Guidance
The relatively quicker procedure, indirect ultrasound guidance relies on ultrasound imaging but not in real-time. The imaging helps healthcare providers determine where the needle or catheter needs to go in advance of the procedure. Due to the risk of organ damage, this type is recommended only if there are large amounts of fluid buildup.
How Does It Work?
When healthcare providers perform paracentesis—whether as part of a diagnosis or treatment—the goal is to collect ascites fluid from the abdomen. They collect it using a needle and syringe. Samples for diagnostic purposes need to be sent to a laboratory for evaluation. Here’s what you can expect from the procedure:
Before the Test
Paracentesis typically takes about half an hour. During this time, you’ll be awake and lying down or sitting. There’s usually no need for an overnight stay. Patients find the procedure tolerable.
Before the procedure, the healthcare provider will perform a physical evaluation. You’ll be asked to empty your bladder prior to paracentesis.
During the Test
First you’ll change into a hospital gown and either lie down on the table or sit as your healthcare provider instructs. The provider then shaves and cleans the area of your abdomen the needle will be entering. The provider may inject a local anesthetic to the targeted area to numb the skin.
If using direct ultrasound guidance, electronic devices called transducers will be placed on the abdomen to help in the production of images. If ultrasound isn’t used, the provider makes a target mark on your skin, such as by drawing an "X" on your belly.
Using a needle, the provider pierces the skin and walls of the abdomen to access the fluid. A syringe takes out the fluid. The provider removes the syringe from the needle as well as the needle, disinfects the area, and uses stitches or a bandage to stop any bleeding.
If the paracentesis is being done for diagnostic purposes, the provider will send a sample of the fluid to a lab for testing.
The Post-Test
Barring any complications, you won’t need an overnight hospital stay—paracentesis is typically an outpatient procedure. You will likely be able to go home once any bleeding has stopped and your blood pressure and temperature are normal. If you had a paracentesis for treatment purposes and had more than five liters (about five quarts) of ascites fluid drawn, you may need to have albumin, a protein, delivered via intravenous line (IV) to prevent low blood pressure.
You'll like be able to go home soon after the paracentesis. You'll also probably be able to resume normal activities, maybe having to wait until you no longer feel any discomfort in the area of the needle insertion.
Risks and Precautions
Generally, paracentesis is a safe, well-tolerated procedure. You can expect some itching or swelling for a day or two as the injection site heals. It's also possible to experience complications. Complications may include:
Persistent leaking of fluid from the injection site
Excess, persistent bleeding
Low blood pressure (hypotension)
Bruising around the injection site
Infection causing redness and pain at the injection site
Organ perforation, which is extremely rare
Paracentesis may not be as safe if you have certain health conditions. It’s recommended that people with disseminated intravascular coagulation—a rare blood clotting disorder—not undergo the procedure. Paracentesis might also want to be avoided if you are pregnant or have any of the following:
Organomegaly, an abnormal enlargement of organs
Ileus, an inability of the intestines to move bowels
Inflamed or enlarged bladder
How to Prepare for Paracentesis
Anyone trained in performing a paracentesis can do the procedure. This may be an internist, emergency department physician, interventional radiologist (a doctor who specializes in using imaging to diagnose and treat conditions and who can perform some procedures), nurse practitioner, general surgeon, or intensivist (critical care doctor).
You might undergo a paracentesis in the hospital or an outpatient clinic.
Consider wearing loose-fitting, comfortable clothes to your appointment so you can easily change out of them before the procedure.
You likely won't have to fast, but your healthcare provider will give you your specific instructions. You should also talk with your provider about whether you need to change your medication or supplement regimen in anyway.
The average cost for an image-guided paracentesis in the U.S. is $586 in ambulatory surgical centers and $930 in the outpatient department of a hospital. If you have insurance, make sure to bring your insurance card.
Results
When paracentesis is used for therapeutic purposes, symptoms that the fluid buildup was causing usually improve quickly. However, it is common for the fluid to build back up.
When paracentesis is used for diagnosis, the samples of ascites fluid is sent to a laboratory for clinical evaluation. There, the sample is evaluated and tested. The results can help determine what is causing your fluid buildup.
The provider who ordered the procedure may give you a call about your results, or you may be able to access them via an online portal. Depending on the results, you may need an appointment to discuss your results and talk about next steps.
Interpreting Your Results
In the laboratory, a pathologist analyzes the fluid sample. This analysis consists of a panel of clinical tests that help detect potential causes of the fluid buildup. It could include a Gram stain, which tests for the presence of bacteria cells in the sample. A positive result means there’s an infection. The pathologist might also perform a cell count of the sample and test the fluid for different markers like albumin, a protein in the blood, and total protein. High or low levels of the different markers could signal what is causing your fluid buildup.
Your healthcare provider will interpret the results and let you know what the testing may have found. Based on what the results show, they might refer you for additional testing or start you on a treatment plan.
A Quick Review
Paracentesis is a procedure used to drain fluid from spaces in your abdomen. It can be used either as a treatment to relieve symptoms the fluid buildup has caused you or as a diagnostic test to see what is causing the buildup. The fluid is taken out with a needle. If paracentesis is being done for treatment purposes, the symptoms the fluid pressure was causing go away quickly. When tested for diagnostic purposes, the fluid sample is sent to a laboratory for testing. Liver cirrhosis is usually determined to be the reason for the buildup, but other conditions like certain cancers and heart failure could be the cause too. A relatively low-risk procedure, paracentesis is performed in outpatient settings using only local anesthesia, meaning you can usually go home in the same day as your procedure.
For more Health.com news, make sure to sign up for our newsletter!
Read the original article on Health.com.
