One-fourth of very low risk kids undergo abdominal CT

A total of 25 percent of children presenting to the emergency department at very low risk for intra-abdominal injuries underwent abdominal CT, results of a study published in the February issue of Annals of Emergency Medicine showed.  A clinical prediction rule that identifies children with blunt torso trauma at very low risk for intra-abdominal injury may obviate CT scanning for some patients.

As the use of CT scanning has spread, concerns about radiation risks among children have arisen. Several small, single-center studies have suggested that children with blunt torso trauma can be risk-stratified through the application of clinical variables.

James F. Holmes, MD, MPH, from the department of emergency medicine at University of California, Davis in Sacramento, and colleagues sought to derive a prediction rule to identify children with blunt torso trauma at very low risk for intra-abdominal injury undergoing intervention.

The prospective, observational cohort study focused on children with blunt torso trauma in the Pediatric Emergency Care Applied Research Network and enrolled 12,044 patients from 20 centers between May 2007 to January 2010.

The researchers defined intra-abdominal injury as any radiographically or surgically apparent injury to the spleen, liver, urinary tract, gastrointestinal tract, pancreas, gallbladder, adrenal gland, intra-abdominal vasculature structure or traumatic fascial defect. Acute intervention was defined as: death caused by intra-abdominal injury, a therapeutic intervention at laparotomy, angiographic embolization caused by bleeding from intra-abdominal injury or administration of intravenous fluids for two or more nights in patients with pancreatic or gastrointestinal injuries.

CT was performed in 5,514 patients, and 761 patients were diagnosed with intra-abdominal injuries. Intra-abdominal injury with acute intervention was identified in 203 patients; 191 of these patients had undergone CT. Eleven of the 12 patients not undergoing CT underwent laparotomy.

Abdominal CT was performed in 542 of the 558 patients with intra-abdominal injury never undergoing intervention and in 4,647 of 11,283 patients without any intra-abdominal injury.

The prediction rule consisted of seven variables, in descending order of importance: evidence of abdominal wall trauma or seat belt sign, Glasgow Coma Scale score less than 14, abdominal tenderness, evidence of thoracic wall trauma, complaints of abdominal pain, decreased breath sounds and vomiting.

The researchers calculated that 42 percent of patients were at very low risk for intra-abdominal injury undergoing acute intervention as identified by the absence of any of the prediction rule variables; 25 percent of these patients underwent CT.

Holmes and colleagues pointed out that strict application of the rule would increase abdominal CT scanning. “For children not at low risk, the rule is meant to be assistive for the clinician by providing evidence to aid clinical decisionmaking. The rule is not intended to suggest that all those who screen positive for one or more variables must undergo abdominal CT scanning,” they wrote. Instead, the rule is designed as a general guide to identify low-risk children in whom CT could be obviated.

The researchers suggested the use of screening lab tests or focused assessment sonography for trauma to help inform decision making and risk stratification among children categorized as low risk. Holmes and colleagues added, in conclusion, that the rule must be externally validated before implementation.