Abdominal ultrasound examination in pregnant blunt trauma patients

Background: The ability of abdominal ultrasound to detect intraperitoneal fluid in the pregnant trauma patient has been questioned. Methods: Pregnant blunt trauma patients admitted to a Level I trauma center during an 8-year period were reviewed. Ultrasound examinations were used to detect intraperitoneal fluid and considered positive if such fluid was identified. Results: One hundred twenty-seven (61%) of 208 pregnant patients had abdominal ultrasound during initial evaluation in the emergency department. Seven patients had intra-abdominal injuries, and six had documented hemoperitoneum. Ultrasound identified intraperitoneal fluid in five of these six patients (sensitivity, 83%; 95% confidence interval, 36-100%). In the 120 patients without intra-abdominal injury, ultrasound was negative in 117 (specificity, 98%; 95% confidence interval, 93-100%). The three patients without intra-abdominal injury but with a positive ultrasound had the following: serous intraperitoneal fluid and no injuries at laparotomy (one) and uneventful clinical courses of observation (two). Conclusion: The sensitivity and specificity of abdominal ultrasonography in pregnant trauma patients is similar to that seen in nonpregnant patients. Occasional false negatives occur and a negative initial examination should not be used as conclusive evidence that intra-abdominal injury is not present. Ultrasound has the advantages of no radiation exposure.