 Hemodynamic evaluation of the effect of RIPC Maneuvers: Intracranial pressure if bolt or external ventricular vein EVD present, blood pressure, oxygen saturation and heart rate will be monitored through the pre-conditioning process. If heart rate or BP changes greater than 20 of baseline and cannot be attributed to anything else the preconditioning will be stopped and allowed to normalize before retrying or be aborted based on bedside nurse, physicians, or research staff discretion. Oxygen saturation will also need to be above 92 at all times and ICP20 when starting or at discretion of the bedside nurse or physician. Glascow Coma Score GSC will be monitored by nursing staff and recorded per ICU protocol. TCD measurements will be performed per ICU protocol. 