Elsevier

Annals of Emergency Medicine

Volume 52, Issue 3, September 2008, Pages 268-273
Annals of Emergency Medicine

Infectious disease/brief research report
Physician Clinical Impression Does Not Rule Out Spontaneous Bacterial Peritonitis in Patients Undergoing Emergency Department Paracentesis

https://doi.org/10.1016/j.annemergmed.2008.02.016Get rights and content

Study objective

We determine whether clinical characteristics and physician assessment are useful in the exclusion of spontaneous bacterial peritonitis in emergency department (ED) patients with ascites requiring paracentesis.

Methods

We conducted a prospective, observational study of ED patients with ascites undergoing paracentesis. Predefined clinical characteristics including historical features and ED vital signs were recorded. Each patient was assessed by 2 separate, blinded physicians for severity of abdominal tenderness and overall clinical suspicion for spontaneous bacterial peritonitis. The primary outcome measures were sensitivity, specificity, and likelihood ratios (LR) of the individual clinical characteristics and the physician assessments. Spontaneous bacterial peritonitis was defined by absolute neutrophil count greater than 250 cells/mm3 or positive fluid culture result.

Results

There were 285 separate physician assessments in 144 patients enrolled with complete data. Spontaneous bacterial peritonitis was diagnosed in 17 (11.8%) patients. Physician clinical impression had a sensitivity of 76% (95% confidence interval [CI] 62% to 91%) and specificity of 34% (95% CI 28% to 40%) for the detection of spontaneous bacterial peritonitis. The lowest negative LR was associated with the presence of any abdominal pain or tenderness (negative LR=0.4); however, the presence of pain/tenderness was also observed in 85% of patients without spontaneous bacterial peritonitis. Six patients (4.2%) with spontaneous bacterial peritonitis had at least 1 physician assessment of little to no risk for spontaneous bacterial peritonitis, and 3 of the 6 subsequently died during their hospitalization.

Conclusion

Clinical characteristics and physician assessment were insufficient in the diagnosis or exclusion of spontaneous bacterial peritonitis in the ED patient undergoing diagnostic or therapeutic paracentesis. This finding supports routine laboratory fluid analysis after ED paracentesis.

Introduction

Diagnostic paracentesis is an important emergency department (ED) procedure in evaluating for spontaneous bacterial peritonitis in the patient with ascites. In addition, therapeutic paracentesis is a mainstay of treatment for ameliorating the discomfort associated with large-volume ascites. Although many patients have their therapeutic paracentesis performed in a scheduled outpatient clinic setting, an increasingly large number of patients without access to primary or specialty care are coming to the ED for therapeutic paracentesis. In the outpatient clinic ED setting, 2 studies examining asymptomatic patients presenting for a therapeutic paracentesis showed a combined 2.5% incidence of spontaneous bacterial peritonitis (defined as absolute neutrophil count >250 cells/mm3) in 545 patients.1, 2 This low incidence of spontaneous bacterial peritonitis in the outpatient setting contrasts with that observed in the hospitalized patient. Studies have demonstrated a 12% incidence of spontaneous bacterial peritonitis in patients admitted with decompensated cirrhosis and an 18% incidence in patients admitted with hepatic encephalopathy.3, 4 It is unknown where the ED patient presenting for paracentesis fits in this spectrum; therefore, the role of routine ascites fluid analysis for spontaneous bacterial peritonitis in the ED patient is less clear. Because mortality is 20% even in treated spontaneous bacterial peritonitis patients, it is important not to miss the diagnosis.5 To our knowledge, no studies exist that examine which patients who present to the ED might be safe candidates for therapeutic paracentesis without ascites fluid analysis. The aim of this study, therefore, is to prospectively determine whether patient clinical characteristics or physician assessment of likelihood of spontaneous bacterial peritonitis is highly sensitive for the detection of spontaneous bacterial peritonitis and thus could reliably rule out spontaneous bacterial peritonitis in the ascites patient.

Section snippets

Study Design

This was a prospective, observational study done to assess the ability of patient clinical characteristics and physician clinical impression to rule out spontaneous bacterial peritonitis in ED ascites patients. A convenience sample of patients was enrolled 24 hours a day during all days of the week. The study was approved by the institutional review board at each facility.

Study Setting and Population

The 3 participating EDs had a combined census of 220,000 patients per year. All 3 EDs have emergency medicine residencies

Results

Among the 3 participating hospitals 155 patients with ascites were enrolled in our study. Eleven patients had paracentesis performed but no laboratory fluid analysis and were excluded, leaving 144 patients with complete absolute neutrophil count data. There were 285 assessments by 106 physicians. There were 65 PGY-2, 60 PGY-3, 18 PGY-4, and 142 faculty physician assessments. Seventeen patients (11.8%) met absolute neutrophil count or culture criteria for spontaneous bacterial peritonitis.

Limitations

Our study is limited by its small number of patients with spontaneous bacterial peritonitis. In addition, determination of physician clinical impression for spontaneous bacterial peritonitis was made before paracentesis was performed. Therefore, ascitic fluid appearance was not used in clinician decisionmaking and might have affected the clinical impression. One retrospective study demonstrated that 98% of patients with spontaneous bacterial peritonitis had peritoneal fluid appearance described

Discussion

In our study, clinical signs, symptoms, and physician impression were poor in ruling out spontaneous bacterial peritonitis. Some degree of abdominal pain was present in nearly all patients with or without spontaneous bacterial peritonitis, whereas fever was uncommon even in those with disease. Other retrospective studies of inpatients have demonstrated poor performance of clinical signs in the diagnosis of spontaneous bacterial peritonitis. Fever, abdominal pain, and encephalopathy were present

References (12)

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Supervising editor: Gregory J. Moran, MD

Author contributions: BC conceived the study. BC and GWH designed the study. BC, HM, and JB supervised the conduct of the trial and data collection. BC, HA, HM, and JB managed the data. BC and HA did all final data analysis, whereas GWH provided statistical advice. BC and HA drafted the article, and all the authors contributed substantially to its revision. BC takes responsibility for the paper as a whole.

Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. The authors have stated that no such relationships exist. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement.

Publication date: Available online April 23, 2008.

Reprints not available from the authors.

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