Emergency physician-performed ultrasound to diagnose cholelithiasis: a systematic review.

OBJECTIVES: The authors sought to determine the diagnostic test characteristics of bedside emergency physician (EP)-performed ultrasound (US) for cholelithiasis in symptomatic emergency department (ED) patients.
METHODS: A search was conducted of MEDLINE, EMBASE, the Cochrane Library, bibliographies of previous systematic reviews, and abstracts from major emergency medicine conference proceedings. We included studies that prospectively assessed the diagnostic accuracy of emergency US (EUS) for cholelithiasis, compared to a criterion reference standard of radiology-performed ultrasound (RADUS), computed tomography (CT), magnetic resonance imaging (MRI), or surgical findings. Two authors independently performed relevance screening of titles and abstracts, extracted data, and performed the quality analysis. Disagreements were resolved by conference between the two reviewers. EUS performance was assessed with summary receiver operator characteristics curve (SROC) analysis, with independently pooled sensitivity and specificity values across included studies.
RESULTS: The electronic search yielded 917 titles; eight studies met the inclusion criteria, yielding a sample of 710 subjects. All included studies used appropriate selection criteria and reference standards, but only one study reported uninterpretable or indeterminate results. The pooled estimates for sensitivity and specificity were 89.8% (95% confidence interval [CI] = 86.4% to 92.5%) and 88.0% (95% CI = 83.7% to 91.4%), respectively.
CONCLUSIONS: This study suggests that in patients presenting to the ED with pain consistent with biliary colic, a positive EUS scan may be used to arrange for appropriate outpatient follow-up if symptoms have resolved. In patients with a low pretest probability, a negative EUS scan should prompt the clinician to consider an alternative diagnosis.