Diagnostic Accuracy of Ultrasound by Emergency Physicians in Patients with Suspected Small Bowel Obstruction (SBO): A Multi-center Study.

Background: Timely diagnosis of small bowel obstruction (SBO) is essential to prevent complications. While computed tomography (CT) is the gold standard for diagnosing SBO due to its high sensitivity and specificity, it has notable limitations, including radiation exposure, high cost, delayed diagnosis, and limited accessibility. Recently, ultrasound has gained attention as a potential alternative in emergency departments (ED) because it is radiation-free, cost-effective, and accessible. This multi-center study seeks to assess the diagnostic accuracy of ultrasound in identifying SBO among patients presenting to the ED. Methods: This multicenter cross-sectional study included 100 patients with suspected SBO, examined by a trained ED physician using ultrasound and confirmed by CT. Ultrasound findings evaluated were excessive gas, bowel wall thickening, interloop free fluid, lumen diameter ≥2.5 cm, and decreased peristalsis. Sensitivity, specificity, and likelihood ratios were calculated for each finding. Results: We found that the most efficient parameters were lumen size greater than 2.5 cm (efficacy: 73%, 95%CI: 63% - 81%), and a decrease in peristalsis (efficacy: 73%, 95%CI: 63% - 81%), The most specific parameters were excessive gas (specificity: 89%, 95%CI: 75% - 97%) and thickening of the bowel wall (specificity: 82%, 95%CI: 66% - 92%). The most sensitive parameters were interloop free fluid (sensitivity: 77%, 95%CI: 65% - 87%) and lumen diameter ≥ 2.5 cm (sensitivity: 77%, 95%CI: 65% - 87%) among other diagnostic findings. Conclusion: Ultrasound may be a useful diagnostic tool for SBO in the ED, offering a potentially efficient and accessible option for diagnosis.