Abdominal paracentesis is a simple bedside or clinic procedure in which a needle is inserted into the peritoneal cavity and ascitic fluid is removed . Diagnostic paracentesis refers to the removal of a small quantity of fluid for testing. Therapeutic paracentesis refers to the removal of 5 liters or more of fluid to reduce intra-abdominal pressure and relieve the associated dyspnea, abdominal pain, and early satiety.
Who Should Perform Paracentesis?
Paracentesis can be performed safely by any clinician who has received proper training. Some hospitals have a dedicated procedure team that performs simple procedures such as paracentesis and central line insertion. These teams, which typically include an experienced clinician or mid-level provider and an assistant, often use an ultrasound machine to guide the procedure. The availability of adequately trained staff is imperative to prevent delays.
Indications, Contraindications, and Special Considerations
Indications – There are several generally accepted indications for abdominal paracentesis
●Evaluation of new onset ascites
●Testing of ascitic fluid in a patient with preexisting ascites who is admitted to the hospital, regardless of the reason for admission
●Evaluation of a patient with ascites who has signs of clinical deterioration, such as fever, abdominal pain/tenderness, hepatic encephalopathy, peripheral leukocytosis, deterioration in renal function, or metabolic acidosis
Performing a paracentesis at the time of admission to the hospital in patients with cirrhosis and ascites may decrease mortality rates. This was examined in a database study that included 17,711 patients with cirrhosis and ascites who were admitted to the hospital with a principle diagnosis of ascites or encephalopathy]. Paracentesis was performed in 61 percent of the patients, and the patients who underwent paracentesis had lower in-hospital mortality rates than those who did not (6.5 versus 8.5 percent, adjusted odds ratio 0.55, 95% CI 0.41-0.74).
In addition to helping to clarify the cause of ascites and evaluating for infection, paracentesis can identify unexpected diagnoses, such as chylous, hemorrhagic, or eosinophilic ascites.
An analysis of the fluid helps determine the cause(s) of the ascites and the likelihood of bacterial infection, and it can identify antibiotic susceptibility of any organisms that are cultured.
However, there are some relative contraindications to paracentesis:
●Patients with clinically apparent disseminated intravascular coagulation and oozing from needle sticks. This occurs in <1/1000 patients with ascites in our experience. Paracentesis can be performed once the bleeding risk is reduced by administering platelets and, in some cases, fresh frozen plasma.
●Primary fibrinolysis (which should be suspected in patients with large, three-dimensional bruises). Paracentesis can be performed once the bleeding risk is reduced with treatment.
●Paracentesis should not be performed in patients with a massive ileus with bowel distension unless the procedure is image-guided to ensure that the bowel is not entered.
●The location of the paracentesis should be modified in patients with surgical scars so that the needle is inserted several centimeters away from the scar. Surgical scars are associated with tethering of the bowel to the abdominal wall, increasing the risk of bowel perforation.
Abnormal coagulation studies and thrombocytopenia — An elevated international normalized ratio (INR) or thrombocytopenia is not a contraindication to paracentesis, and in most patients there is no need to transfuse fresh frozen plasma or platelets prior to the procedure. Seventy percent of patients with ascites have an abnormal prothrombin time, but the actual risk of bleeding following paracentesis is very low (less than 1 percent of patients require transfusion) ]. Exceptions are patients with clinically apparent disseminated intravascular coagulation or clinically apparent hyperfibrinolysis, who do require treatment to decrease their risk of bleeding.
The safety of paracentesis in patients with cirrhosis has been documented in several studies:
●A prospective study of 1100 large-volume paracenteses documented no bleeding complications with no pre- or post-procedure transfusions required despite INRs as high as 8.7 and platelet counts as low 19,000/mL.
●In another report (in which occasional patients received prophylactic fresh frozen plasma, platelets, or desmopressin [DDAVP]), severe bleeding was observed in only 9 of 4729 paracenteses (0.19 percent) ]. The mortality rate attributable to the procedure was 0.016 percent. Eight of the nine patients who bled had renal failure, suggesting that the qualitative platelet dysfunction associated with renal failure contributed to the bleeding risk. Thus, it may be reasonable to use DDAVP before performing paracentesis in patients with cirrhosis and renal failure, although no studies have formally established a benefit.
●A somewhat higher complication rate (1.6 percent) was reported in a prospective study of 515 paracentesis in patients with cirrhosis . Five patients bled, three developed infections, and two died. However, one of the complications was “catheter residue broken into abdominal wall”, which taken together with the relatively high complication rate, raises concern as to whether there were specific technique-related factors that may have contributed to the adverse outcomes.
Many clinicians inappropriately transfuse fresh frozen plasma or platelets, or avoid performing minor procedures altogether, in patients with cirrhosis because of concern that patients are “auto-anticoagulated.” However, there is now convincing evidence disproving the common misconception. The liver makes coagulation factors as well as anticoagulant proteins . As a result, liver disease can lead to a hypocoagulable state or a hypercoagulable state. The relative balance or imbalance of these factors is not reflected in conventional indices of coagulation, such as the prothrombin time (PT), activated partial thromboplastin time (aPTT), or INR
Transfusion of blood product to reverse the coagulopathy before paracentesis is discouraged since it is not supported by the available data, can delay the procedure, exposes the patient to risk of transfusion, and is costly .The routine administration of fresh frozen plasma prior to paracentesis would lead to transfusion of approximately 140 units of plasma to prevent transfusion of two units of red cells .
For the vast majority of patients, we will perform a paracentesis without giving fresh frozen plasma or platelets. The exceptions are in patients with clinically apparent disseminated intravascular coagulation or clinically apparent hyperfibrinolysis . These conditions occur in less than 1 in every 1000 patients with ascites. In patients with disseminated intravascular coagulation, we will administer platelets and, in some cases, fresh frozen plasma prior to performing a paracentesis. For patients with hyperfibrinolysis we treat with aminocaproic acid or intravenous tranexamic acid.
Harinath Sheela, MD moved to Orlando, Florida after finishing his fellowship in gastroenterology at Yale University School of Medicine, one of the finest programs in the country. During his training he spent significant amount of time in basic and clinical research and has published articles in gastroenterology literature. His interests include Inflammatory Bowel Diseases (IBD), Irritable Bowel Syndrome (IBS), Hepatitis B, Hepatitis C, Metabolic and other liver disorders. He is a member of the American Gastroenterological Association (AGA), the American Society for Gastrointestinal Endoscopy (ASGE) and the American Association for the Study of Liver Diseases (AASLD) and Crohn’s Colitis foundation (CCF). Dr. Sheela is a Clinical Assistant Professor at the University of Central Florida School of Medicine. He is also a teaching attending physician at Florida Hospital Internal Medcine Residency and Family Practice Residence (MD and DO) programs.
By Harinath Sheela, MD