Paracentesis is a common medical procedure performed to remove fluid (ascites) that has accumulated abnormally within the abdominal cavity, specifically in the peritoneal space. The procedure involves inserting a thin needle or catheter through the abdominal wall to access and drain the fluid. The medical professional who performs this procedure depends on the patient’s specific circumstances and the hospital or clinic setting.
The Purpose of Fluid Removal
The decision to perform a paracentesis is driven by two distinct indications: diagnosis and therapy. A diagnostic paracentesis involves removing a small sample of fluid, typically 25 to 50 milliliters, for laboratory analysis. Analyzing this fluid determines the underlying cause of the ascites, such as liver disease or cancer, or checks for infection, most notably Spontaneous Bacterial Peritonitis (SBP). Timely diagnosis of SBP is important because it is a severe infection that increases the risk of complications.
Therapeutic paracentesis is performed to relieve the physical discomfort and complications caused by a large volume of fluid, often referred to as tense ascites. Removing large amounts of fluid, sometimes up to 5 or more liters, alleviates symptoms like abdominal distension, pain, and shortness of breath. Patients with chronic liver conditions, such as cirrhosis, may require this procedure repeatedly for symptom management.
Qualified Medical Professionals
A wide range of trained clinicians routinely perform paracentesis, reflecting its status as a fundamental procedure in ascites management. Internal medicine physicians, often called hospitalists, frequently perform the procedure at a patient’s bedside. Gastroenterologists and hepatologists specialize in the digestive system and liver diseases, and are extensively trained since ascites is often a complication of advanced liver disease. These specialists are usually the first to be consulted for most cases of ascites.
For cases that are more technically challenging, such as when the fluid collection is small or loculated, or if the patient has had extensive prior abdominal surgery, an interventional radiologist may be required. These specialists use advanced imaging, like computed tomography (CT) or fluoroscopy, to guide the needle into the fluid pocket with precision. In some settings, emergency physicians also perform paracentesis, particularly when using real-time ultrasound guidance in urgent situations.
Advanced practice providers, including physician assistants and nurse practitioners, also perform therapeutic paracentesis under specific institutional protocols and supervision. In some specialized hospital units, trained specialist nurses or GI endoscopy assistants may be authorized to perform large-volume paracentesis. The choice of professional often depends on the patient’s location, the complexity of the case, and the urgency of the fluid removal. Evidence suggests that bedside procedures performed by medicine-trained clinicians can lead to comparable patient outcomes and lower hospital costs compared to procedures performed in the radiology suite.
Procedure Settings and Patient Preparation
The setting for a paracentesis can vary widely, from the patient’s bedside in a hospital room to an outpatient clinic or a specialized interventional radiology suite. Before the procedure, the medical team obtains informed consent, explaining the purpose, risks, and benefits to the patient. A necessary preparation step is ensuring the patient empties their bladder, naturally or with a catheter, to minimize the risk of accidental puncture.
The patient is typically positioned supine, lying on their back, often with the head slightly elevated (45 to 90 degrees). This positioning allows gravity to assist in pooling the fluid and helps displace the bowel. Ultrasound imaging is a standard part of preparation, allowing the clinician to locate a safe pocket of fluid and identify and avoid blood vessels and underlying organs. Patients taking blood-thinning medications may need to temporarily stop or adjust their dosage before the procedure to minimize the chance of bleeding.
Understanding the Steps of the Procedure
Once the optimal entry site is marked, the procedure begins with sterile preparation of the skin, typically using an antiseptic solution like chlorhexidine or povidone-iodine. A local anesthetic, such as lidocaine, is then injected into the skin and deeper tissues down to the peritoneum to numb the area. The clinician inserts the needle into the abdominal wall, often applying gentle, intermittent suction to the attached syringe. This technique confirms entry into the fluid space and prevents tissue from blocking the needle tip.
For diagnostic purposes, a small volume of fluid is collected into sample tubes. When performing a therapeutic drain, a catheter is advanced over the needle into the peritoneal cavity, and the needle is withdrawn. The catheter is then connected to a drainage system, such as a vacuum bottle or drainage bag, to allow the fluid to flow out. The “Z-track” method, which involves pulling the skin slightly before insertion, may be used to create an offset needle path and prevent fluid leakage after removal. After the desired amount of fluid is drained, the catheter is removed, and a sterile dressing is applied to the puncture site.