Background Plain film radiography (x-ray) is often the initial study in patients with suspected small bowel obstruction (SBO) to expedite patient care.

Objective To compare bedside ultrasonography (US) and x-ray for the detection of SBO.

Methods This was a prospective study using a convenience sample of patients presenting to the emergency department (ED) with abdominal pain, vomiting, or other symptoms suggestive of a SBO. Patients were evaluated with US prior to x-ray and CT. US was performed by emergency physicians (EPs) who completed a 10 min training module and five prior US exams for SBO. The criterion standard for the diagnosis of SBO was the results of CT read by board-certified radiologists.

Results In all, 76 patients were enrolled and evaluated with US for SBO. A total of 33 (43%) were diagnosed as having SBO. Dilated bowel on US had a sensitivity of 91% (95% CI 75 to 98%) and specificity of 84% (95% CI 69 to 93%) for SBO, compared to 27% (95% CI 14 to 46%) and 98% (95% CI 86 to 100%) for decreased bowel peristalsis on US. x-Ray had a sensitivity of 46.2% (95% CI 20.4 to 73.9%) and specificity of 66.7% (95% CI 48.9 to 80.9%) for SBO when diagnostic, but was non-diagnostic 36% of the time.

Conclusion EP-performed US compares favourably to x-ray in the diagnosis of SBO.