Traumatic Brain Injury

Traumatic brain injury (TBI) is disruption of brain function or structure caused by an external force. The force may be a direct blow, rapid acceleration-deceleration, rotation, blast, or penetrating injury. The visible lesion may be a contusion, diffuse axonal injury, skull fracture, or extra-axial or intraparenchymal bleeding. Concussion is at the milder end of the spectrum, but it remains a clinical brain injury even when acute imaging is normal. Primary injury happens at the time of trauma. Mechanical deformation can tear axons, vessels, and tissue; that damage cannot be reversed after it occurs. Secondary injury evolves afterward through impaired oxygen delivery, hypotension, cerebral edema, inflammation, seizures, fever, and disordered autoregulation. These processes may reduce cerebral blood flow and enlarge the original injury, so prevention and early recognition of secondary insults are central nursing priorities. The rigid skull contains brain tissue, blood, and cerebrospinal fluid. When the volume of one component rises and compensation is exhausted, intracranial pressure (ICP) rises. Higher ICP can reduce cerebral perfusion pressure (CPP) and can progress to tissue shift and herniation. CPP is calculated as mean...