Baylor University Medical Center Proceedings July 2017 - 262

Imaging and clinical predictors of spontaneous bacterial
peritonitis diagnosed by ultrasound-guided paracentesis
Andrew Sideris, Pooja Patel, Hearns W. Charles, MD, James Park, MD, David Feldman, MD, and Amy R. Deipolyi, MD, PhD

Spontaneous bacterial peritonitis (SBP) is a potentially life-threatening
complication of ascites diagnosed by paracentesis. We determined
predictors of SBP to facilitate patient selection. The 301 paracenteses
performed in 119 patients (51 women, 68 men) from July to November
2015 were retrospectively reviewed. Presentation, lab data, depth of
the deepest ascites pocket on ultrasound, total volume of ascites removed, absolute neutrophil count, and complications were studied. Of
301 paracenteses, 16 (5%) diagnosed SBP. On univariate analysis, SBP
was associated negatively with history of cirrhosis and positively with
history of cancer, abdominal pain, greater depth of the fluid pocket,
prior SBP, and leukocytosis. Multivariate analysis using these variables
to predict SBP was significant (P < 0.0001); only depth of the largest
fluid pocket (P = 0.008) and complaint of abdominal pain (P = 0.006)
were independent predictors. Receiver-operator curve analysis showed
that a 5-cm cutoff of pocket depth yielded 100% sensitivity and 32%
specificity. Two (0.1%) hemorrhagic complications occurred, one causing
death and one necessitating laparotomy. In conclusion, deeper ascites
pockets and abdominal pain are independent predictors of SBP. When
the largest ascites pocket is <5 cm, the probability of SBP is nearly
negligible. Given the potential for hemorrhagic complications, findings
may help triage patients for paracentesis.

aracentesis is recommended for symptomatic relief, diagnosis of ascites etiology, and exclusion of spontaneous bacterial peritonitis (SBP), which can be fatal in
20% of patients (1, 2). Paracentesis has been shown to
shorten hospital stay and prevent complications such as hyponatremia, hepatic encephalopathy, and hepatorenal syndrome
(3). One major complication of paracentesis is hemorrhage,
with an incidence of <1% (4). Studies have not deﬁned risk
factors for bleeding complications (5). Given its low complication rate and diagnostic and therapeutic value, paracentesis is
performed on a large scale. Among nearly 18,000 admissions
for ascites or encephalopathy, diagnostic workup for over 60%
of patients included paracentesis (6). Given that the exposure
to paracentesis procedures is so large, hemorrhage, while rare,
is encountered. Certain paracenteses are performed only for diagnostic purposes, to evaluate for SBP, an uncommon diagnosis
(7). Given the rarity of SBP and the potential for hemorrhagic
complications, it would be helpful to deﬁne factors associated
262

with SBP to aid in patient selection and avoid unnecessary
adverse events. The aim of this study was to identify patient
and imaging characteristics that increased the risk for SBP to
optimize the diagnostic role of paracentesis and minimize patient exposure to procedural risks.
METHODS
This retrospective study was approved by the institutional
review board and was compliant with the Health Insurance
Portability and Accountability Act. Consecutive ultrasoundguided paracentesis procedures from July 2015 to November
2015 at a single institution were analyzed. Indications were
for therapeutic and/or diagnostic purposes. Paracentesis was
performed by physician members of the vascular and interventional radiology section. After preparing and draping in
usual sterile technique and administering lidocaine for local
anesthesia, using ultrasound guidance an 8Fr pigtail drainage
catheter (Total Abscession, Angiodynamics, Latham, NY) or
an 18-gauge needle was advanced into the largest pocket and
secured to the skin for drainage, with an image of the largest
pocket saved, as described previously (4). All specimens were
sent for evaluation of cell count and culture. For therapeutic
paracentesis, all ﬂuid was removed; for paracentesis performed
only for diagnostic purposes, 20 to 60 cc were removed. SBP
was deﬁned by absolute neutrophil count (ANC) ≥250 cells/
mm3 and/or positive ﬂuid culture (8). Ascitic ﬂuid characteristics and the patient's underlying condition, presenting
symptoms, and laboratory data were also analyzed. In total,
309 paracentesis procedures were performed over the study
period. Eight were excluded due to the absence of laboratory or
imaging data. The 301 remaining procedures were performed
in 119 patients (51 women, 68 men) with a mean age of 62.5
± 1.2 years.
From New York University School of Medicine, New York, New York (Sideris,
Patel); South Florida Vascular Associates, Coconut Creek, Florida (Charles); New
York University Hepatology Associates, New York University Langone Medical
Center, New York, New York (Park, Feldman); and Interventional Radiology Service,
Memorial Sloan Kettering Cancer Center, New York, New York (Deipolyi).
Corresponding author: Amy Deipolyi, MD, PhD, Interventional Radiology Service,
Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY
10065 (e-mail: deipolya@mskcc.org).
Proc (Bayl Univ Med Cent) 2017;30(3):262-264

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