Modeling Intracranial Fluid Flows and Volumes during Traumatic Brain Injury to Better Understand Pressure Dynamics

─We describe a computer model of intracranial pressure (ICP) dynamics that evaluates clinical treatment options for elevated ICP during traumatic brain injury (TBI). The model uses fluid volumes as primary state variables and explicitly models fluid flows as well as the resistance, compliance, and pressure associated with each intraand extracranial compartment (arteries and arterioles, capillary bed, veins, venous sinus, ventricles, and brain parenchyma). The model evaluates clinical events and therapies such as intraand extra-parenchymal hemorrhage, cerebral edema, cerebrospinal fluid drainage, mannitol administration, head elevation, and mild hyperventilation. The model is able to replicate observed clinical behavior in many cases, including elevated ICP associated with severe cerebral edema following subdural, epidural, or intraparynchemal hematoma. The model also mimics cerebrovascular regulatory mechanisms that are activated during TBI. Keywords—intracranial pressure (ICP), traumatic brain injury (TBI), dynamic modeling, therapeutic modeling.