Prediction rule could reduce unnecessary CT scans in kids

Last Updated: 2017-02-13

By Will Boggs MD

NEW YORK (Reuters Health) – A new prediction rule could reduce unnecessary CT scans in children at very low risk for blunt intra-abdominal injury, researchers report.

"Not all children need an abdominal CT scan just based on the mechanism of injury,” said Dr. Christian J. Streck from The Medical University of South Carolina Children's Hospital in Charleston.

“Children in major collisions or other major traumatic events may be safely observed, transferred to a pediatric specialty center, or even discharged in the absence of significant risk factors for intra-abdominal injury,” he told Reuters Health by email.

Most children with blunt abdominal trauma present to adult trauma centers, and more than half undergo a CT scan based on adult protocols as part of their trauma evaluation. This exposes them to relatively large doses of radiation and places them at increased risk for future radiation-induced malignancy.

Dr. Streck and colleagues sought to derive a clinical prediction rule to identify children at very low risk for intra-abdominal injury (IAI) after blunt abdominal trauma (BAT) for whom a CT scan of the abdomen would be unnecessary.

Among 2,188 children with BAT, 34% had an abnormal abdominal examination, 11.9% were diagnosed with an IAI, and 45.3% underwent abdominal CT scan from the trauma bay, the researchers report in the Journal of the American College of Surgeons, online January 24.

The prediction rule incorporated five variables: aspartate transferase (AST) >=200 U/L, abnormal abdominal physical examination, abnormal chest x-ray, complaint of abdominal pain, and an abnormal pancreatic enzyme (amylase or lipase).

Based on the absence of these five variables, 33.7% of children were at very low risk for IAI. Of these, 23% had an abdominal CT scan, which represents 17% of the abdominal CT scans performed in those with a mechanism concerning for BAT.

The negative predictive value for the rule was 99.4% for IAI and 100% for IAI requiring intervention.

“On the other end of the spectrum, children with multiple risk factors present were much more likely to have an injury or an injury requiring intervention and so the prediction rule can help the evaluating physician decide about whether to order a CT and provide parents with some shared decision making based on the number of risk factors present and likelihood of injury,” Dr. Streck said.

“The prediction rule should be used to screen children who present to the hospital after a significant trauma (like a high-speed motor vehicle crash, ATV accident, or being struck by a moving vehicle) to determine whether they are at very low risk of having an abdominal injury (like a spleen laceration or a bowel perforation),” Dr. Streck concluded. “Patients who are deemed ‘very low risk’ based on the rule can likely avoid a CT in the absence of any major risk factors.”

“Many of these patients get admitted to the hospital anyway for management of other non-abdominal injuries (brain/skull, orthopedic, facial trauma, etc.) and are a ‘captive audience’ to re-examine the abdomen later,” he said. “Those who do not need admission for other injuries and are deemed ‘very low risk’ could likely be discharged home if stable in the ED.”

Dr. Streck cautioned, “This prediction rule still needs to be validated prospectively in a new population to prove it will work. The prediction rule was developed in pediatric trauma centers so its application in an adult trauma center and/or a non-trauma center needs further evaluation.”

SOURCE: http://bit.ly/2lHE4tG

J Am Coll Surg 2017.