Vasospasm in Pediatric Traumatic Brain Injury

Inclusion Criteria: 1. admission to Duke University Children's Hospital; 2. age 5 days to 15 years; 3. a diagnosis of a TBI with a GCS 3-15; 4. capable of adequate TCD ultrasound examination; 5. and presence of intravenous or arterial access (blood) and/or an EVD for cerebrospinal fluid (CSF) and/or Foley catheter/ability to void unassisted (urine) biomarker collection unless they are excluded based on the exclusion criteria. Exclusion Criteria: * the presence of previously diagnosed significant neurodevelopmental delay, * a diagnosis of non-traumatic intracranial hemorrhage and * parents/legal guardians who do not speak or understand English.