Ascites can be recognized on physical examination as abdominal distention and the presence of a fluid wave.
Abdominal paracentesis is a safe and effective diagnostic and therapeutic procedure used in the evaluation of a variety of abdominal problems , including ascites, abdominal injury, acute abdomen, and peritonitis.
Therapeutic paracentesis is used to relieve respiratory distress due to increased intra-abdominal pressure caused by ascites.
Ascites fluid can be used to help determine the etiology of ascites, as well as to evaluate infection or the presence of cancer.
Paracentesis is a procedure commonly performed in patients with advanced liver disease and cirrhosis .
The fluid that collects in the abdomen, called ascites, is the result of a complication of cirrhosis, called portal hypertension.
Scarring of the liver, which occurs in cirrhosis, results in reduced blood flow through the liver and increased pressure in the portal vein.
The portal vein is the main vein that drains blood from the abdomen to the liver.
Any abnormality in the blood flow through the portal vein produces an increase in pressure and a leakage of fluid into the abdominal cavity, which causes the development of ascites.
Ascites in the abdomen can lead to abdominal pain, infection of the fluid, which is called peritonitis, as well as problems related to eating and breathing.
While small amounts of ascites fluid in the abdomen can be treated with a low-salt diet and diuretics, larger amounts of ascites can lead to additional problems for patients.
The anatomy of the abdominal wall is shown.
The insertion sites can be the midline or the transverse oblique muscle, which is lateral to the thicker rectus abdominis muscles.
Paracentesis is usually performed in radiology under ultrasound guidance.
Empty the patient’s bladder voluntarily or with a Foley catheter.
Place the patient in a horizontal supine position and tilt the patient slightly to the side of the collection (usually the lower left quadrant).
The midline and lateral approaches can be used for paracentesis, but the left lateral technique is more commonly used.
Because the blind is relatively fixed on the right side.
The left lateral approach avoids the air-filled intestine that usually floats in ascites fluid.
Slightly roll your hips down on the table on the side of the needle insertion to make that quadrant of the abdomen more dependent.
The insertion sites are displayed.
Prepare the skin with a solution of povidone iodine or chlorhexidine and allow it to dry while applying sterile gloves and a mask.
Center the sterile drape about one third of the distance from the umbilicus to the anterior iliac crest.
The skin of the abdomen is clean and a 1% solution of lidocaine with Epinephrine is applied.
Next, a 2-inch needle is inserted perpendicular to the skin to infiltrate the deep tissues and peritoneum under anesthesia.
The catheter with the introducer is inserted through the skin.
The non-dominant hand stretches the skin to one side of the puncture site and the needle is inserted.
The catheter is advanced until you feel a “pop” and the catheter enters the peritoneum.
Pressure on the skin is released after the introducer enters the peritoneum.
The catheter is advanced into the abdominal cavity.
The introducer is removed and the syringe is placed. If no fluid comes out, the catheter is rotated, slightly withdrawn or advanced until fluid is obtained.
If there is still no fluid, the procedure is aborted and an alternative site or method is tried.
Ascites fluid can be removed by connecting a three-way stopcock or one-way valve, a 60cc syringe in one arm, and a drain tube and bag in the other arm.
If lavage is desired, such as to detect hemoperitoneum after trauma, the IV tubing is connected to the 3-way stopcock.
Excess fluid is removed, and then 700 to 1,000 ml of Ringer’s lactate or normal saline is infused into the abdominal cavity.
The patient is gently moved from side to side. Then the fluid is removed, a trap and suction arrangement can be used.
In most circumstances, between one and four liters can be removed.
In more than 75% of cases, patients can control their ascites with diet and diuretics.
Large-volume paracentesis is generally reserved for patients with more advanced liver disease, or those who do not respond to medical and dietary intervention.
The presence of ascites in patients with cirrhosis would be an indication to consider liver transplantation.
Most ascetic fluids re-accumulate quickly.
Some experts recommend that no more than 1.5 liters of fluid be removed in a single procedure.
Patients with severe hypoproteinemia may lose additional albumin in the reaccumulation of ascites fluid and develop acute hypotension and heart failure.
Cancer patients with malignant effusions may also require repetitive therapeutic paracentesis.
Intravenous volume and vascular volume may be required in these patients if larger volumes are removed.
After the procedure, the catheter is gently withdrawn and direct pressure is applied to the wound.
The characteristics of the fluid are observed and the fluid is sent to the laboratory for analysis, ensuring that no infection is present.
If the insertion site continues to leak fluid after 5 minutes of direct pressure, suture the site with a vertical mattress suture. Apply a pressure dressing.
The gauze bandage should be applied when unusual and persistent drainage occurs.
After diagnostic paracentesis, fluid should be sent to the laboratory for Gram staining, culture, cytology, protein, glucose, and lactate dehydrogenase levels, and with a differential blood cell count.
A polymorphonuclear cell count of more than 500 cells per mm3 is highly suggestive of bacterial peritonitis.
In pancreatitis, an elevated level of amylase is found in the peritoneal fluid or a level higher than the serum level of amylase.
Fluid with abundant blood in the abdomen greater than 100,000 red blood cells per mm3 indicates a more serious trauma or perforation of an abdominal organ.
The classic positive test for hemoperitoneum is the inability to read through the paracentesis lavage fluid.
Disposable paracentesis or thoracentesis kits generally include the following:
- Antiseptic swabs.
- Cortina fenestrada.
- 1% lidocaine, 5 ml ampoule.
- Syringe, 10 ml.
- 2 inch long injection needle.
- Blade scalpel No. 11.
- 14-gauge catheter over 17-gauge × 6-inch needle with a three-way stopcock or one-way valve, self-sealing valve, and a 5 mL Luer Lock syringe.
- Syringe, 60 ml.
- Set of tubes with roller clamp.
- Drainage bag or vacuum container.
- Sample bottles or collection bottles.
- Chiffon, 4 inches × 4 inches.
- Adhesive bandage.
Ascites fluid evaluation is used to help determine the different etiologies of diseases such as:
- Differentiate transudate versus exudate, to detect the presence of cancer cells or address other considerations.
- Evaluation of blunt or penetrating abdominal injury.
- Evaluation of the acute abdomen.
- Evaluation of acute or spontaneous peritonitis.
- Evaluation of acute pancreatitis.
It is also used in the relief of respiratory distress due to increased intra-abdominal pressure.
This procedure is contraindicated in cases of:
- Acute abdomen requiring immediate surgery (absolute contraindication).
- Severe thrombocytopenia, platelet count greater than 20 × 103 / μL.
- Coagulopathy (international standardized index> 2.0).
- In patients without clinical evidence of active bleeding, routine laboratories such as prothrombin time, activated partial thromboplastin time, and platelet counts may not be needed before the procedure.
- Severe intestinal bloating (extra caution should be exercised).
- Multiple previous abdominal operations.
- Pregnancy (absolute midline procedure).
- Distended bladder that cannot be emptied with a Foley catheter (relative contraindication).
- Obvious infection at the intended insertion site (relative contraindication).
- Severe hypoproteinemia (relative contraindication).
- Intra-abdominal adhesions.
Pediatric patients may not cooperate with catheter placement.
Due to the risks of damage to vessels, nerves, etc., consider sedation with intramuscular injections or oral administration of sedative medications such as Versed and Ketamine.
Post procedure instructions
The patient should be instructed to monitor bleeding from the area and return if abnormal bleeding is observed.
The patient should also be careful in case of pain, numbness or discomfort in the area and inform the doctor.
The patient should also monitor for evidence of infection.
Lastly, the patient should be advised to clean with soap and warm water and dry the area.
Abdominal radiographs should be obtained prior to paracentesis, because air can be introduced during the procedure and may interfere with interpretation.
Complications of paracentesis include:
- Perforation of the bladder and stomach, colon, or small intestine.
- Intestinal perforation.
- Laceration of a major blood vessel.
- Loss of catheter or guide wire in the peritoneal cavity.
- Hematomas of the abdominal wall.
- Perforation of the pregnant uterus.
- Risk of infection.
- Persistent leak from the puncture site.
- Dilutionary hyponatremia.
- Hepatorenal syndrome.
In most situations, patients do not require any additional pain relievers or anesthesia when the procedure is performed.
Similarly, when patients are discharged at home, no additional pain medications are needed.
In fact, most patients are comforted when the fluid and associated abdominal pressure is relieved.
In most cases, paracentesis is done as an outpatient procedure.
In situations where patients require large volume paracentesis more than once every two weeks, this would be an indication that they have developed refractory ascites.
Endovascular radiologists can insert a stent between the portal vein and the hepatic vein, restoring blood flow through the liver and reducing portal hypertension created by cirrhosis.
Multiple and misplaced needle insertions during paracentesis procedures can increase the risk of bleeding complications.
Bedside ultrasound can improve patient safety associated with needle-based procedures.