Efficacy of Ketamine in Children With Severe Brain Injury for Brain Cell Protection

Inclusion Criteria: * are 1 month to 16 years of age; AND * are admitted to the PICU following severe TBI (any GCS 3-8 inclusive) within 8 hours after the injury; AND * are intubated and ventilated for the management of TBI; AND * are anticipated to have an indwelling arterial or venous catheter for blood sampling during the first three days of study enrollment; AND * have an intra-cranial pressure (ICP) monitoring device for management of TBI. Exclusion Criteria: * are less than 4 kilograms in weight upon admission * are less than 1 month of age; * are greater than 16 years of age; * have a clinical diagnosis of non-accidental TBI; * have suffered immersion injury or prolonged hypoxic injury (lasting greater than 10 minutes); * have a known allergy to ketamine; * have a planned removal of endotracheal tube or the removal of central venous catheter AND arterial catheter within 72 hours of study enrollment; * have a current history of neuromuscular disease; * have a current history of hepatic failure; * have a current history of glaucoma * require chronic treatment with anti-epileptic drugs (AEDs) or devices; * more than 8 hours have elapsed from the time of injury to PICU admission; * have documentation of a positive pregnancy test at the time of enrollment; * if there is a lack of commitment to aggressive intensive care therapies (the subject is either on a DNR status due to pre-existing medical condition, or the family decides to withdraw support prior to participation in the study due to other multiple severe injuries and organ failures resulting from the trauma).