Paracentesis
Peri-Procedural Management of Coagulopathy, Thrombocytopenia, & Antithrombotic Agents (last updated 01/2021)
Indications
Evaluation of new-onset ascites
Evaluation of ascites of known etiology in the setting of acute decompensation
Therapeutic drainage of large volume or diuretic resistant ascites
Contraindications
Relative contraindication if severe coagulopathy or thrombocytopenia
Multiple previous abdominal surgeries or previous intra-abdominal infections with adhesions(consider ultrasound-guided approach)
Morbid obesity or hepatosplenomegaly (consider ultrasound-guided approach)
Severe bowel distention
Superficial cellulitis at proposed point of entry
Inability of patient to cooperate with procedure
Thoracentesis Tray with 8 Fr. Catheter and universal drainage set [contents]
Anatomic Considerations
Structural impediments to the safe introduction of a paracentesis needle can include the bladder, bowel, and pregnant uterus.
The bladder is normally tucked into the recess of the pelvis. However, neuropathically distended bladders caused by pharmacologic agents or medical conditions should preferably be emptied by voiding or by catheterization to avoid puncture.
Intestines typically float in ascitic fluid and will move safely away from a slowly advancing paracentesis needle. Even if penetrated by an 18- to 22-gauge needle, leakage of intestinal contents will not occur unless the intraluminal pressure is 5- to 10-fold greater than normal conditions. Therefore, US guidance may be indicated in cases of suspected adhesions or bowel obstruction.
In second- and third-term pregnancy, an open supraumbilical or US-assisted approach is preferred. The abdomen should be carefully inspected for evidence of abdominal hematoma, engorged veins, or superficial infection, and these sites should be strictly avoided.
The best site of entrance for repeat paracentesis is determined by the patient's prior experience, so this question should be asked of the patient.
In absence of prior experience, two sites are preferred. One site is approximately 2 cm below the umbilicus in the midline where the fasciae of the rectus abdominis join to form the fibrous, thin, avascular linea alba. Large collateral veins may occasionally be present and should be avoided, as should suspected areas of skin infection.
If the patient has midline scarring, or if prior experience has been positive, the preferred alternate site is in either lower quadrant, approximately 4 to 5 cm cephalad and medial to the anterior superior iliac spine. The importance of remaining lateral to the rectus sheath is to avoid the inferior epigastric artery.
Patients with a large quantity of ascites can readily undergo the procedure in the supine position with the head of the bed slightly elevated.
Those with lesser amounts of fluid may profit from a lateral decubitus position with introduction of the needle into the midline or dependent lower quadrant. Some clinicians prefer to use the lateral decubitus position routinely because the bowel tends to float upward and away from the path of the needle.
Rarely, patients may need to be placed in a facedown, hands-on-knees position. In the patient with multiple abdominal scars or suspicion of compartmentalized abdominal fluid for any reason, US guidance is prudent.
Technique
Informed consent
Every procedure, every time. Documentation is paramount particularly when considering performing a procedure. Every therapeutic procedure, despite the best intent, carries with it inherent risks along with the potential benefits. As healthcare providers it is our duty to adequately educate our patients regarding these risks and benefits, providing information and answering questions in lay terms so that the patient (or their surrogate) can make an informed medical decision.
“Informed consent” comprises several different aspects which should be documented in the chart prior to performing any procedure:
Name of the procedure and the diagnosis for which it is being performed.
Risks of the procedure and their likelihood of occurring.
Benefits of the procedure as well as likelihood of information/advantages gained.
Alternative therapies if available, as well as their risks and benefits.
Opportunity for the patient (or surrogate) to ask questions and discuss other options.
Documentation of the patient’s (or surrogate’s) ability to provide adequate informed consent.
Many institutions have “Informed Consent” templates available which help providers review and document each of these important aspects. Make sure these consents are signed and available in the chart prior to any procedure.
Dire situations may arise where a patient is unable to provide informed consent and a surrogate is unavailable; if the patient requires a potentially life-saving procedure emergently and may die without it, the procedure may be performed without informed consent. Once the acute emergency has been dealt with, informed consent from the patient or a designated surrogate should be obtained retroactively as soon as possible.
Sterile Technique
One area of significant concern in healthcare today is the incidence of nosocomial infections, particularly those borne out of treatment delivered rather than the presenting illness. Hospitals and healthcare groups are now looking closely at the rate and incidence of infections arising from internally-performed procedures. Considering the vast amount of care delivered on daily basis and the growing bacterial resistance to antibiotics, maintaining sterility of bedside procedures is paramount.
Before opening your procedure kit, make sure to clearly identify the pertinent anatomy for your procedure. Clearly mark your planned point of entry. At this point, using Chloraprep or Betadine swabs (Chloraprep is now preferred given evidence it may in fact better disinfect and antagonize skin flora), gently sterilize the area starting at your point of entry and moving in concentric circles outward. Feel free to sterilize a wide area; this allows you more room to maneuver during the procedure. Repeat this process two or three times to ensure effective skin sterilization. For most procedures, maximum barriers should be used. These include a surgical cap, aface shield or goggles, sterile gloves, and a sterile gown. Maximum barriers also include washing your hands thoroughly before the procedure and using sterile drapes during the procedure. Oftentimes the draping provided in the procedure kits does not provide enough sterile workspace to comfortably perform the procedure. All wards should have packs of sterile towels stocked and available; do not hesitate to use these to extend the sterile workspace if necessary. If you require an assistant to perform the procedure, take time to ensure they are following proper aseptic technique as well.
While these steps may seem cumbersome, it is the responsibility of everyone delivering patient care to reduce infectious risk wherever and whenever possible. Take care to document that these guidelines were followed in your post-procedure note.
Catheter insertion
Obtain patient’s informed consent and have consent available in chart; perform a “time-out” to confirm that this procedure will be performed on the correct site, on the correct patient.
Check the patient’s most recent labs, particularly CBCs and coagulation studies.
Ideally, platelets should be >50,000 and INR no more than 2-3 times the upper limit of normal
Remember that these are only relative contraindications and this procedure can be safely performed in the presence of thrombocytopenia and coagulopathy.
If you have any concerns about performing a procedure due to an uncorrected coagulopathy, you should discuss this with your supervising practitioner first.
Perform a careful abdominal exam and mark your intended site prior to sterilizing the area.
Be sure that you feel for an enlarged or low-lying liver and spleen as these may interfere with your site and increase risk of significant bleeding.
Preferred sites for paracentesis are below the lateral edge of the rectus muscles in the lower abdominal quadrants bilaterally. This minimizes difficulty introducing the needle and usually offers the safest point of entry below the liver and spleen.
If only a small amount of ascites is present or the patient has a complicated abdomen (multiple previous abdominal surgeries with adhesions, multiple surgical scars, morbid obesity, loculated ascites), you may contact Radiology to mark the site by ultrasound. The patient must remain in the same position after the site is marked; paracentesis must be performed ASAP following marking to reduce risk of losing site and orientation due to patient movement or fluid shifts.
Make the work area as comfortable for yourself as possible, i.e. good lighting, elevate bed to a comfortable height, secure a work area and trash receptacle within easy reach to minimize movements during the procedure.
Place a pillow underneath the patient on the side opposite your intended puncture site tilting the patient toward you. Viscous bowel floats in fluid and, unless adhered to peritoneum from inflammation or scar tissue from previous surgery, should float away from the puncture site.
Consider using ultrasound to mark the site of entry if there is difficulty identifying an appropriate entry point by exam.
Prepare the area following proper aseptic technique; apply maximum barriers (sterile gloves/gown, face shield) to help reduce contamination risk.
Identify all sharps in the kit prior to starting your procedure. Check all syringes to make sure they draw back easily.
Anesthetize the area taking care to aspirate before injecting to assure the needle is not in a vessel. If it is, retract the needle slowly and completely and apply pressure; reassess your placement and try again. Once you enter the peritoneum (often denoted by a ‘pop’ and return of yellow ascitic fluid) deposit the remainder of the anesthetic.
After anesthetizing the area, take your scalpel and insert it approximately 0.5cm to create an opening for your catheter.
Gently advance your catheter with the finder needle in place through the tract you have created. Make sure to slowly aspirate continuously as you advance to make sure you are not entering a vessel; do NOT remove the syringe or flush forward as this can introduce air into the peritoneum.
Once the Caldwell catheter is advanced into the peritoneal space (again denoted by return of ascitic fluid) you can carefully remove the finder needle.
Once your Caldwell catheter is in place, fill your 60cc syringe with ascites first. Use this to fill your culture bottles if you are doing bedside inoculation (must apply a clean needle to the syringe before inoculating). If only performing a diagnostic paracentesis, you may retract your catheter while covering the site and place a pressure dressing over the wound.
If you are performing a therapeutic paracentesis, engage the slide lock on the tubing, connect the tubing to the Caldwell catheter and then connect the other end to the vacuum bottle. Release the slide lock and fluid should begin to flow.
If you are not getting adequate flow, you can adjust the catheter or patient positioning until flow is restored.
As more fluid is obtained, the bowel may move forward and occlude the catheter. You may gently pull back the catheter to restore flow remembering that the catheter cannot be advanced again.
Remember to engage the slide lock prior to changing vacuum bottles and hold the tubing upward to prevent spraying/leakage. Turn the flow back on once the tubing is secured into the new vacuum bottle.
Once a safe amount of ascites has been obtained or flow cannot be restored, slowly remove the soft catheter and apply pressure to the puncture site. Apply a pressure dressing to the wound and keep the patient turned onto the side opposite the puncture to reduce pressure on the forming clot.
Specimen Handling
At least one 60 cc syringe should be reserved for laboratory analysis. You will need to put a red cap on this syringe before labeling and transport to the laboratory. If you choose to inoculate culture bottles at the bedside, use a clean needle (i.e. hasn’t been through skin) to place 10 ml of ascitic fluid in each of the culture bottles.
Results interpretation
Typical studies obtained for a diagnostic paracentesis include:
Cell count and differential
Gram stain and culture
LDH, albumin, glucose (serum-to-ascites albumin gradient is the most helpful)
Cytology
Depending on appearance or differential diagnosis, other peritoneal fluid studies include amylase (poor study though may help assess if pancreatic in origin), cytology (sent in 1 liter cytology bag if concern for malignant ascites), and triglycerides (evaluation for chylous ascites).
Recognizing & managing complications
Peritonitis(from introduced air, introduced infection, and bowel perforation)
A common cause of free air and peritonitis following paracentesis is introduced air from catheter insertion or removal; this is usually self-limited and resolves with time. If there are any symptoms of perforation (fever, elevated WBC count, hypotension, worsening pain, patient appears clinically ill), start the work-up for bowel perforation immediately.
If suspicion for perforation or peritonitis, obtain a STAT abdominal X-ray to evaluate for the presence of free air.
If clinical suspicion is high for bowel perforation and X-ray is inconclusive, obtain a STAT CT abdomen without PO contrast and contact General Surgery immediately. Start antibiotics immediately if there is any concern for introduced infection or bowel perforation.
Hemorrhage
Usually occurs in the setting of coagulopathy though can also occur following traumatic paracentesis.
Reverse the reversible (giving FFP and Vitamin K for elevated INR), replace the replaceable (giving PRBCs and IV fluid for significant anemia and hypotension).
Wound dehiscence and persistent leakage
Lay the patient on the side opposite the puncture site for 2-6 hours to reduce pressure on the wound and clot disruption.
If leakage persists, a simple stitch can be placed to close the wound though closure usually occurs with conservative management and time.
Superficial hematoma and wound infection
Usually self-limited complications that require supportive care and antibiotics if concern for skin infection.
Hypotension/Circulatory dysfunction/Renal failure
The following OHSU pharmacy protocol can be used to determine whether and how much albumin should be given following large volume paracentesis.
References
This guide was adapted from:
Chapter 43: Peritoneal Procedures. Clinical procedures in emergency medicine. Eds James Roberts and Jerris Hedges. 5th edition, 2004.
Introduction to Inpatient Procedures: A Resident-to-Resident Guide.University of Minnesota Internal Medicine Residency AHCC Ambulatory Rotation. Second Edition, Revised October 2007 (available via www.mededportal.org)