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33: OPTIC NERVE SHEATH DIAMETER CHANGES IN CHILDREN WITH VARYING DEGREES OF INTRACRANIAL PRESSURE

Introduction/Hypothesis: The aim of this study is to evaluate ultrasonographic optic nerve sheath diameter (ONSD) measurements in children who are suffering from varying degrees of traumatic brain injury (TBI). Methods: All children admitted to the PICU and evaluated for TBI at either Children’s National Health System or Johns Hopkins Children’s Center were enrolled in this prospective observational trial. Patients were divided into three age subgroups (<24 months, 24-59 months, and 60-200 months) and four diagnostic subgroups (brain dead, major head trauma with elevated intracranial pressure (ICP), major head trauma with normal ICP and minor trauma with no ICP measurements). Student’s t-test was used to compare mean ONSD between diagnosis subgroups. Receiver operator characteristics curves were created to determine the optimal ONSD cutoff thresholds to differentiate between the 4 diagnostic subgroups. Results: Of the 76 enrolled children, 20 had brain death, 18 had major head trauma with high ICP (mean ICP of 28mmHg (±8.5)), 18 had major head trauma with normal ICP (mean ICP of 8mmHg (±3.3)), and 20 suffered minor head trauma with an average Glasgow Coma Score of 14.2(±1). The average ONSD for the brain dead group was 5.33mm (±0.62), the high ICP group was 5.11mm (±0.46), the normal ICP group was 4.31mm (±0.5), and the minor head trauma group was 3.73mm (±0.37). There was a significant difference in smaller average ONSD of minor head trauma patients compared with major head trauma and normal ICP (p <0.01) and a greater difference compared to patients with major trauma and high ICP (p<0.01). Optimal ONSD cutoffs were 4.03mm and 5.0 mm, respectively. There was no significant difference in ONSD between patients with major head trauma with high ICP and brain dead patients (p-0.27). Conclusions: ONSD can be used to distinguish children with minor head trauma from those with major head trauma with either normal or high ICP. However, changes in ONSD cannot differentiate between a child who is brain dead and a child who has increased ICP secondary to major head trauma.