NOninVasive Intracranial prEssure From Transcranial doppLer Ultrasound Development of a Comprehensive Database of Multimodality Monitoring Signals for Brain-Injured Patients

"In this study, the investigators will primarily use the monitor mode of the Transcranial Doppler (TCD, non-invasive FDA approved device) to record cerebral blood flow velocity (CBFV) signals from the Middle Cerebral Artery and Internal Carotid Artery. TCD data and intracranial pressure (ICP) data will be collected in the following four scenarios. Each recording is up to 60 minutes in length:~External ventricular drain (EVD) closed to drainage for a 24 hour period as part of the EVD weaning protocol per standard of care (SOC): The Initial reading will be done within 4 hours of EVD closing. The second reading will be done within 4 hours of anticipated removal of EVD.~EVD closed most of the time and opened to drainage when the ICP becomes elevated per SOC~EVD with Intra-Parenchymal fiber optical ICP sensor per SOC~Intra-Parenchymal fiber optical ICP sensor per SOC"