Association between the "seat belt sign" and intra-abdominal injury in children with blunt torso trauma.

OBJECTIVES: To determine the association between an abdominal "seat belt sign" (SBS) and intra-abdominal injury (IAI) in children presenting to the emergency department (ED) after blunt trauma.

METHODS: The authors performed a prospective, observational study of children at risk for IAI who presented to a Level 1 trauma center following a motor vehicle collision (MVC) during a two-year period. Physical examination findings were recorded prior to abdominal imaging or surgery. The SBS was defined as an area of erythema, ecchymoses, and/or abrasions across the patient's abdominal wall resulting from a seat belt restraint. Patients were divided into two cohorts based on the presence or absence of an SBS, then further subdivided based on abdominal tenderness or pain. The authors compared patients with and without SBS, and those with and without abdominal pain or tenderness for the presence of IAI.

RESULTS: Three hundred ninety children, of whom 46 (12%, 95% CI = 9% to 15%) had an SBS, were enrolled. IAIs were more common in patients with, versus without, an SBS (14/46 vs. 36/344, relative risk 2.9; 95% CI = 1.7 to 5.0; p < 0.001). Patients with an SBS were more likely to have gastrointestinal injuries than those without an SBS (12/46 vs. 7/344, relative risk 12.8; 95% CI = 5.3 to 31; p = 0.001). Pancreatic injuries were also more common among patients with an SBS (3/46 vs. 1/344, relative risk 22; 95% CI = 2.4 to 211; p = 0.006). There was no difference in the prevalence of solid organ injuries between those with and without an SBS (4/46 vs. 34/344, relative risk 0.9, 95% CI = 0.3 to 2.4; p = 1.00). None of the six patients (0%, 95% CI = 0 to 39%) with an SBS, but without abdominal pain or tenderness, had IAIs.

CONCLUSIONS: Patients with an SBS after an MVC are more likely to have IAIs than patients without an SBS, predominately due to a higher rate of gastrointestinal injuries. Patients with an SBS but without abdominal pain or tenderness appear to be at low risk for IAI.