Objectives: Ketamine is an effective, safe, rapid, short-acting anesthetic drug, and – contrary to all other anesthetic drugs - it does not decrease blood pressure. It is widely believed that Ketamine increases intracranial pressure (ICP), which prevents its use in many emergency situations, including trauma and specifically in patients with traumatic brain injury (TBI) and with increased ICP. Based on our previous clinical experience in patients with ICP monitoring, Ketamine did not increase ICP. We therefore hypothesize that Ketamine decreases – rather than increases – ICP.