Blunt abdominal trauma: Screening US in 2,693 patients

PURPOSE: To evaluate the accuracy of screening abdominal ultrasonography (U S) in patients with blunt abdominal trauma. MATERIALS AND METHODS: Patients with blunt abdominal trauma underwent US. T he abdomen and pelvis were scanned for free fluid, the visceral organs were assessed for heterogeneity, and duplex US was performed if necessary. Empt y bladders were filled with 200-300 mt of sterile saline through a Foley ca theter. US findings were considered positive if free fluid was present or i f parenchymal abnormalities that could be consistent with trauma were detec ted. Screening US results were compared with findings of diagnostic periton eal lavage, repeat US, computed tomography (CT), cystography, surgery, and/ or autopsy and/or the clinical course. RESULTS: Findings from 2,693 US examinations were evaluated and were positi ve in 145 of 172 patients with injuries (sensitivity, 84%) and 64 (89%) of 72 patients who ultimately underwent laparotomy with surgical repair of inj uries. False-negative findings were retroperitoneal injury, bowel injury, a nd intraperitoneal solid organ injury without hemopetitoneum. No patient wi th false-negative findings died. Specificity of US was 96% (2,429 of 2,521 patients), and overall accuracy was 96% (2,574 of 2,693 patients). Positive predictive value was 61%(145 of 237 patients), and negative predictive val ue was 99% (2,429 of 2,456 patients). CONCLUSION: Abdominal US is useful in screening for injury in patients with blunt abdominal trauma, and its use represents a notable change in institu tional practice. Diagnostic peritoneal lavage is rarely performed, and CT i s used when screening US findings are positive, when injury is clinically s uspected despite negative US findings, or when US is not available.