Utilization of ultrasound for the evaluation of small bowel obstruction: A systematic review and meta-analysis.

INTRODUCTION: Small bowel obstruction (SBO) is a common presentation to the Emergency Department (ED). While computed tomography (CT) is frequently utilized to confirm the diagnosis, this modality is expensive, exposes patients to radiation, may lead to time delays, and is not universally available. This study aimed to determine the test characteristics of ultrasound for the diagnosis of SBO.

METHODS: PubMed, CINAHL, Scopus, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were assessed for prospective trials evaluating the accuracy of ultrasound for the detection of SBO. Data were double extracted into a predefined worksheet and quality analysis was performed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.

RESULTS: This systematic review identified 11 studies comprising 1178 total patients. Overall, ultrasound was found to be 92.4% sensitive (95% CI 89.0% to 94.7%) and 96.6% specific (95% CI 88.4% to 99.1%) with a positive likelihood ratio of 27.5 (95% CI 7.7 to 98.4) and a negative likelihood ratio of 0.08 (95% CI 0.06 to 0.11).

DISCUSSION: The existing literature suggests that ultrasound is a valuable tool in the diagnosis of SBO with a sensitivity and specificity comparable to that of CT. Ultrasound may save time and radiation exposure, while also allowing for serial examinations of patients to assess for resolution of the SBO. It may be particularly valuable in settings with limited or no access to CT. Future studies should include more studies in the Emergency Department setting, comparison of probe choices, and inclusion of more pediatric patients.