Diagnostic accuracy of secondary ultrasound exam in blunt abdominal trauma.

Background: In stable patients with blunt abdominal trauma, accurate diagnosis of visceral injuries is crucial.

Objectives: To determine whether repeating ultrasound exam will increase the sensitivity of focused abdominal sonography for trauma (FAST) through revealing additional free intraperitoneal fluid in patients with blunt abdominal trauma.

Patients And Methods: We performed a prospective observational study by performing primary and secondary ultrasound exams in blunt abdominal trauma patients. All ultrasound exams were performed by four radiology residents who had the experience of more than 400 FAST exams. Five routine intraperitoneal spaces as well as the interloop space were examined by ultrasound in order to find free fluid. All patients who expired or were transferred to the operating room before the second exam were excluded from the study. All positive ultrasound results were compared with intra-operative and computed tomography (CT) findings and/or the clinical status of the patients.

Results: Primary ultrasound was performed in 372 patients; 61 of them did not undergo secondary ultrasound exam; thus, were excluded from the study.Three hundred eleven patients underwent both primary and secondary ultrasound exams. One hundred and two of all patients were evaluated by contrast enhanced CT scan and 31 underwent laparotomy. The sensitivity of ultrasound exam in detecting intraperitoneal fluid significantly increased from 70.7% for the primary exam to 92.7% for the secondary exam. Examining the interloop space significantly improved the sensitivity of ultrasonography in both primary (from 36.6% to 70.7%) and secondary (from 65.9% to 92.7%) exams.

Conclusions: Performing a secondary ultrasound exam in stable blunt abdominal trauma patients and adding interloop space scan to the routine FAST exam significantly increases the sensitivity of ultrasound in detecting intraperitoneal free fluid.