Blunt abdominal trauma: Screening US in 2,693 patients

PURPOSE: To evaluate the accuracy of screening abdominal ultrasonography (US) in patients with blunt abdominal trauma. MATERIALS AND METHODS: Patients with blunt abdominal trauma underwent US. The abdomen and pelvis were scanned for free fluid, the visceral organs were assessed for heterogeneity, and duplex US was performed if necessary. Empty bladders were filled with 200-300 mt of sterile saline through a Foley catheter. US findings were considered positive if free fluid was present or if parenchymal abnormalities that could be consistent with trauma were detected. Screening US results were compared with findings of diagnostic peritoneal 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 positive in 145 of 172 patients with injuries (sensitivity, 84%) and 64 (89%) of 72 patients who ultimately underwent laparotomy with surgical repair of injuries. False-negative findings were retroperitoneal injury, bowel injury, and intraperitoneal solid organ injury without hemopetitoneum. No patient with 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 value 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 institutional practice. Diagnostic peritoneal lavage is rarely performed, and CT is used when screening US findings are positive, when injury is clinically suspected despite negative US findings, or when US is not available.